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Answers t o Questions for Volume
4,
Number 3
Numbered references correspond
with
th e citations
in
th e original articles and
so
are
not
listed here.
References in roman numerals are
not
listed
in
th e origina l article; instead they can be found at the end
of
each set
of
answers.
Complications
of
assisted reproductio n
Ovarian hyperstimulation syndrome
(OHSS)
1 is commonly associated with the use of oral ovulation
induction agents.................................................. FALSE
2 increases in incidence with age. .........................
FALSE
3
in
i t s
mild form, occurs in more than
50
of
in
vitro
fertilisation (IVF) treatment cycles
...................... FALSE
4 i s
more likely to increase in severity
if
pregnancy
ensues. ................................................................... TRUE
5 in association with IVF can be reduced by using
progesterone for luteal support.
.........................
TRUE
Discussion
OHSS is
a
potentially life-threatening complication
classically associated with ovarian stimulation using
gonadotrophins.
It
rarely occurs with the administration of
oral ovulation induction agents such as clomiphene citrate.
Risk factors for the development of OHSS include: young
age, low body weight, polycystic ovaries, high dose of
gonadotrophins, large number of oocytes retrieved, high
oestradiol level on the day of human chorionic
gonadotrophin (hCG) administration, use of hCG for luteal
support, and ensuing pregnancy.2 OHSS may be classified as
mild, moderate or severe according to the Golan
classification.6Mild OHSS occurs in
23-33
of treatment
cycles, moderate in 3 6 of cycles and severe in 0.3-0.5 .'
Using progesterone for luteal-phase support rather than
hCG reduces the incidence of OHSS withou t having a
negative effect on pregnancy rates.'*
Regarding the management of
OHSS,
6 biochemical consequences include hypokalaemic
acidosis
.................................................................. FALSE
7 paracentesis i s contraindicated for symptomatic relief
of ascites. ..............................................................
FALSE
8 intravenous diuretics are indicated if the urinary
output is less than 30 ml/hr. ................................
FALSE
9
thromboprophylactic measures should be employed
for patients admitted to hospital.
....................... TRUE
10
physical exercise may increase the risk of ovarian
torsion
.................................................................... TRUE
Discussion
OHSS is associated with increased capillary permeability
and leakage of protein-rich fluid from the intravascular
space, which results in haemoconcentration and ascites.
Haematological and biochemical consequences include an
increase in haematocrit, leukocytosis, hyponatraemia and
hyperkalaemic acidosis. Correction of the hypovolaemia by
intravenous infusion will restore renal perfusion and,
hence, urine production. Diuretics are contraindicated.
They induce
a
diuresis by removing fluids from the
intravascular compartment and have no effect on the
ascites or the course of the disease.
Heparin (either conventional or low molecular weight)
and antiembolic stockings should be prescribed as
prophylaxis against deep venous thrombosis. Paracentesis,
carried out either transabdominally or transvaginally, is
indicated for symptomatic relief of large volumes of ascites.
In addition to symptomatic relief, this also results in
improved renal function, improved blood osmolarity,
reduced haemoconcentration and reduced pulmonary
compromise. Patients should be advised to avoid strenuous
activity, which increases the risk of ovarian torsion.
However, complete bed-rest should be avoided
as
it
increases the risk of thromboembolism.
With re ard to early pregnancy loss associated with
assistec reproduction,
11
there is an increased rate compared to natural
conception. ............................................................ TRUE
12
embryo transfer techniques may contribute to an
increased risk of ectopic pregnancies. .................
RUE
13 heterotopic pregnancy rates are in the region of 5 .
.............................................................................. FALSE
14 bilateral salpingectomy
is
recommended to reduce
the risk of ectopic pregnancy in patients undergoing
IVFACSI..................................................................
FALSE
Discussion
The apparent increase in miscarriage associated with IVF
appears t o be multifactorial, wi th infert ilit y itself,
regardless of cause, being of major significance.
Miscarriage rates as high as
28
have been reported in
infertile women who conceive spontaneously.
The ectopic pregnancy rate varies between
2-11
in
reported series of IVF pregnancies. The aetiology of
ectopic pregnancy after IVF-embryo transfer
i s
multifactorial, wi th tubal disease being the main factor. The
technique of embryo transfer may also contribute to the
increased risk of ectopic pregnancy, for example through
forcing the embryos into the tubal ostia by hydrostatic
pressure. Laparoscopic clipping
of
the proximal end of a
hydrosalpinx or salpingectomy would prevent the
occurrence of tubal pregnancies in patients with
hydrosalpinges and has, at the same time, been shown to
increase their chance of a successful outcome with IVF.*
Heterotopic pregnancy
is
estimated to occur in 1 of IVF
pregnancie~.'~
t
s
likely, however, that a significant number
are undetected in the presence of an ongoing intrauterine
gestation.
Concerning the obstetric outcome
of
assisted
reproduction,
15
the perinatal mortality rate associated wi th singleton
pregnancies is similar to that of an age-matched
the Human Fertilisation and Embryology Authority
(HFEA) prohibits the transfer o f more than two
embryos. FALSE
17 blastocyst transfer does not increase the rate of
multiple pregnancy as long as only three blastocysts
are transferred.
.................................................... FALSE
spontaneous conception control group. ............
ALSE
16
Discussion
The perinatal mortality rate in assisted reproduction
singleton pregnancies, even when matched for age, parity
and fetal sex,
is
greater than in spontaneously conceived
pregnancies. Perinatal mortali ty is increased seven-fold
50 003
Royal College
of
Obstetricians and Gynaecologists
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Answers to Questions for Volume 4, Number 3
among triplets and five-fold among twitxu Therefore,
reducing the proportion of multiple pregnancies among
IVF conceptions should contribute to a significant overall
reduction in perinatal mortal ity and morbidity. Currently, in
the
UK,
HFEA guidelines allow for the transfer of no more
than three embryos. The RCOG guidelines recommend that
no more than two embryos be transferred. In the future a
move towards transfer o f single blastocysts in women with
high reproductive potential and two blastocysts in others
should help to reduce the increase in perinatal mortality
due to multiple pregnancy.
According t o the 'Golan' classification for O S S
18 maximum ovarian diameters of >10cm may be
associated with mild OHSS.
.................................. TRUE
19 clinical ascites indicates grade 3
OHSS. ..............ALSE
20 an isolated hydrothorax does not indicate severe
disease.
................................................................. FALSE
Discussion
Table 1. Golan Classification of ovarian hyperstimulation
syndrome
Mild
Moderate
Severe
Grade 1: abdominal distension and
discomfort.
Grade 2: grade 1 plus nausea, vomiting,
and/or diarrhoea; ovaries en arged
5-12 crn.
Grade 3: features of mild
OHSS
plus
ultrasonic evidence of ascites.
Grade 4: features of moderate OHSS
plus clinical ascites and/or hydrothorax
with dyspnoea.
Grade
5:
grade 4 plus decreased blood
volume, increased blood viscosity,
hypercoagulability, diminished renal
perfusion and function.
Additional reference
i
Schenker JG, Weinstein
D
Ovarian hyperstimulation
syndrome:
a
current survey. Fertil
Steril
1978;30:255-68.
Unsafe abortion: a preventable problem
The following statements are true:
21 The induced abortion rate per 1000 women
i s
significantly higher in developed than developing
countries.
.............................................................. FALSE
22 A
rise
in contraceptive practice
is
initially associated
wi th a rise in abortion rate.
................................. TRUE
23 On average, one woman in ten wi ll have one induced
abortion before reaching the menopause.........
ALSE
Discussion
The abortion rate, per 1000 women of fertile age,
is
similar
in developed and developing countries (39 and 34
respectively). Contraceptive prevalence and induced
abortion rates sometimes rise in parallel in communities
where couples are beginning to try t o have fewer children.
Later,
as
fert i l i ty falls, high contraceptive use is associated
with lower abortion rates. On average, every woman now
entering her fertile years will have one abortion before
reaching the menopause.
Concern ng mo rta
ity
and morbidity,
24 the mortal ity associated wi th some tradit ional
abortion techniques
is
up to 500-times higher than
vacuum aspiration abortion performed by a trained
individual.
.............................................................. TRUE
25
in Africa the risk of death from induced abortion
is a t
least 500 times greater than in a developed country.
................................................................................ TRUE
26 about 13% of maternal deaths worldwide are
associated with abortion.
..................................... TRUE
27 despite restrictive laws regarding abortion in India,
malaria
st i l l
remains
a
greater cause of death than
unsafe abortion....................................................
FALSE
Discussion
The risk of death from first-trimester unsafe abortion using
traditional techniques i s up to 500 times higher than
abortion using vacuum aspiration.' The World Health
Organization estimates that, of the 515 000-585000
maternal deaths that occur across the world each year, 13%
are abortion related.gData have shown that in Africa there
are 680 deaths for every 100000 abortions whereas in
developed countries, where most abortions performed are
safe, the death rate is between 0.2-1.2 (per 100000
abortions).' In India between 15 000-25
000
women die
each year
as
a result of unsafe abortion; it
is,
therefore,
responsible for more deaths than malaria.
Regarding solutions for unsafe abortion,
28
29
30
in India safe abortion
i s
limited by the availability of
university-trained doctors
.................................... TRUE
vacuum aspiration enables most incomplete abortions
to be treated as day cases.
................................... TRUE
when post-abortion contraceptive advice was given,
the number of women using contraception in Bolivia
rose eight-fold.......................................................
TRUE
Discussion
Although India liberalised
i t s
abortion law in 1970, access
to safe abortion
is st i l l
limited as only university-trained
doctors can legally carry out abortions. Following manual
vacuum aspiration for incomplete abortion, most women
can be discharged from the hospital or clinic within a few
hours.
As part of post-abortion care, women should be
counselled and given contraceptive advice. A study on
contraceptive use before and after counselling revealed hat
in Bolivia contraceptive use before such intervention was
only 10%. Following intervention this figure rose to 88%.
Regarding manual vacuum aspiration (MVA),
31
32
33
34
Discussion
In Bangladesh abortion, or menstrual regulation,
i s
considered a legal family planning method. There
is
an
estimated 10000 individuals trained to perform MVA,
approximately half of which are doctors and the others are
health workers. MVA equipment can cost
as
little as
USS5.00, a weighted cost o f 87% less than D&C. The
equipment can be reused many times, but it is important
that the syringe is kept clean and the cannulae are
sterilised. This method can be used to perform abortions up
to a menstrual age of 12 weeks.
Concerning
the
use of rnisoprostol,
35
36
in Bangladesh approximately half of the trained MVA
practitioners are not doctors ...............................
TRUE
the equipment can be reused many times .........
RUE
this method can only be used up to
a
menstrual age
of 10 weeks.
.........................................................
FALSE
the weighted cost is more than 50% cheaper than
D&C.
....................................................................... TRUE
it
is effective as an abortifacient only when used
orally.
....................................................................
FALSE
when used as an abortifacient in countries where the
procedure remains illegal there has been no change
in the incidence of septic abortions
ALSE
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37 there have been reports of an increased risk of
ectopia vesicae (exstrophy of the bladder) following
the unsuccessful use of misoprostol. ...................TRUE
38 the American manufacturers of misoprostol do not
recommend it for use as an abortifacient...........TRUE
Discussion
Misoprostol can be used to terminate pregnancy when
used either orally or vaginally. Where women have access
to misoprostol, even in areas where abortion is illegal, the
number of hospital admissions for septic abortions
i s
falling. Misoprostol
i s
manufactured by Searle and
marketed under the tradename Cytotec , fo r the
treatment of gastric and duodenal ulcers. Misoprostol
is
not licensed for use
as
an abortifacient and the
manufactures do not support i t s use for this purpose.
There have been reports of abnormalities in children
born following the unsuccessful use of misoprostol as an
abortifacient, including ectopia vesicae (exstrophy of the
bladder), Moebius syndrome (paralysis of the facial
muscles),
I
mb defects, hyd ocephaIus and
a
rth og yposis.
Regarding the politics
of
abortion,
39
40
f i f t y percent of the world's women of reproductive
age live in countries with restrictive laws..........ALSE
overseas aid provided by Britain forbids the use of
taxpayers' money to support safe abortion.......FALSE
Discussion
There are 1.4 billion women of reproductive age in the
world, 26% of these women live in countries wi th highly
restrictive abortion laws. Only the United States permits safe
abortion inside the country while forbidding the use of
overseas aid t o help women obtain safe abortions
elsewhere.
Management of urge urinary incontinence
Urge urinary incontinence s
41 most commonly due to idiopathic detrusor
overactivi y.............................................................
TRUE
42 often associated wi th frequency and nocturia.
.TRUE
43 rarely caused by factors extrinsic to the bladder.
..............................................................................
FALSE
Discussion
Urge incontinence is most frequently caused by idiopathic
detrusor overactivity but has many other potential causes.
Causes that are extrinsic to the bladder include external
pressure (e.g. pregnancy), psychosocial factors (e.g.
dementia) and iatrogenic causes (e.g. diuretics and other
drugs);
it
can also arise due to other medical conditions
(e.g. diabetes). The most common symptoms are frequency,
urgency and nocturia.
Idiopathic detrusor overactivity
44
45
46
47
i s cured by pharmacotherapeutic treatments in over
50% of cases......................................................... FALSE
can reliably be diagnosed on a history of frequency,
urgency and nocturia. ......................................... FALSE
i s
often caused by excessive fluid intake.
..........FALSE
is
usually due to intrinsic disease of the detrusor
muscle .................................................................. FALSE
Discussion
While symptoms of idiopathic detrusor overactivity can
usually be ameliorated with behavioural and pharma-
cotherapeutic treatments
it is
rarely cured. Urodynamic
assessment
is
the only way of obtaining a clear diagnosis of
the cause of urinary incontinence
as
symptomatology
is
often misleading.
Frequency of voiding is often caused by excessive fluid
intake but concentrated urine i s known to worsen the
symptoms of detrusor instability, as is excessive caffeine
intake. It i s as yet unclear whether the cause of detrusor
overactivity is myogenic or neurogenic.
Urodynamic assessment (UDA)
48
49
50
may be more accurate if ambulatory techniques are
employed.
..............................................................
TRUE
findings usually correlate well with the severity and
types of symptoms experienced......................... FALSE
is being superseded by ultrasound of the bladder in
the diagnosis of detrusor instability. .................
FALSE
Discussion
UDA
is
mandatory
if
surgery, particularly repeat surgery, for
incontinence s to be undertaken. UDA is required to make
the diagnosis of idiopathic detrusor overactivity, however,
empirical treatment of urge incontinence also has a
recognised role. Often there is no significant relationship
between the reported severity and type of symptoms and
the actual urodynamic variables. Ambulatory urodynamics
are currently only being used in the research setting but are
thought to be more physiological and perhaps more
accurate. Ultrasound evaluation of bladder wall thickness
is
useful
if
outflow obstruction
is
suspected.
In the treatment
of
idiopathic detrusor overactivity,
51
52
53
54
55
56
bladder dril l
i s
unlikely to be successful in the younger
patient.
.................................................................
FALSE
routine cystodistension does not provide good long-
term benefit. TRUE
slow release preparations have fewer side effects than
immediate release equivalents. ...........................
TRUE
anticholinergic drugs are generally well tolerated.
..............................................................................
FALSE
imipramine should be used as
a
first-line treatment.
FALSE
surgery
i s
reserved for intractable symptoms.
TRUE
Discussion
Bladder drill, although requiring good motivation,
is
much
more successful in the younger patient. Alternative
therapies such as acupuncture, hypnotherapy, and
transcutaneous electrical nerve stimulation have shown
promise in the treatment of idiopathic detrusor overactivity
but have not yet been rigorously evaluated. Controlled-
release preparations of oxybutynin are just as effective as
immediate-release preparations but are associated wi th
a
lower incidence of dry mouth (68% versus 87%).
Anticholinergic drugs lack specificity for the muscarinic
receptor subtypes and as a result have an extensive adverse
effect profiles. Evidence for the value of imipramine as a
treatment
is
conflicting and, therefore, this should not be
used as a first-line treatment. Cystodistension was formerly
routinely used to treat idiopathic detrusor overactivity but
has been shown to be of l i t t le long-term benefit. More
radical surgical procedures are reserved for the most
refractory cases.
Regarding muscarinic receptors,
57 M3 receptors are found in the bladder.
..............RUE
58 M2 receptors are found in the salivary glands..FALSE
59 oxybutynin is a nonselective muscarinic receptor
antagonist.
........................................................... FALSE
60 darifenacin i s an M3 receptor antagonist.
..........
TRUE
Discussion
There are five types of muscarinic receptor within the body
(Ml-M5). The M2 and M3 receptors are found within the
bladder; M2 receptors predominate but the M3 receptor
seems to mediate he main part of bladder contraction. M3
receptors are also found in the salivary glands, the
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4,
Number 3
lachrymal glands and the bowel, which explains the adverse
effect profiles of many drug treatments for idiopathic
detrusor overactivity. Oxybutynin,
a
tertiary amine,
is
a
highly selective M1 and M3 muscarinic receptor antagonist.
Darifenacin s a highly selective M3 receptor antagonist.
Impact
of
contraception on subsequent fertility
Following cessation
of
the combined oral contraceptive
pill (COC)
61
62
63
less than 30 of women wil l ovulate in the first cycle.
.............................................................................. FALSE
there
is
an increased risk of miscarriage
...........
ALSE
women should be advised to use a barrier method of
contraception for three months before they attempt
to conceive.
..........................................................
FALSE
Discussion
The return of ovulation following cessation of the
combined oral contraceptive pill i s rapid and around 70
of women will ovulate in the first cycle. Women who
conceive immediately following cessation of the combined
pi ll can be reassured that there
is
no evidence of increased
risk of miscarriage or fetal abnormality. There
is
no
scientific evidence that women need to use an alternative
method of contraception on cessation of the combined pill
prior t o attempting t o conceive.
With regard
t o
'post-pill amenorrhoea',
64
65
66
more than 5 of women remain amenorrhoeic after
six months ............................................................ FALSE
it i s more common in women who lose weight when
using COC. ............................................................. TRUE
if
it
lasts longer than six months, then investigation is
warranted. ............................................................. TRUE
Discussion
'Post-pill amenorrhoea' affects around 1 of women six
months after stopping the combined pill.
It
may signify the
unmasking of an underlying gynaecological abnormality
such
as
polycystic ovary syndrome, hyperprolactinaemia or
a premature ovarian failure
so
these conditions should be
excluded. Loss of weight while taking the combined pill i s
associated with 'post-pill amenorrhoea' although the exact
mechanism of this is not understood.
After discontinuing depot medroxyprogesteroneacetate
67
ovulation does not return on average until after
12
months ................................................................. FALSE
68
around
90
of women will have conceived by
24
months................................................................... TRUE
69
the delay in return to fer t i l i ty is thought t o be due to
delayed metabolism of crystalline deposits.
.......
TRUE
Discussion
Ovulation returns on average four to five months following
the last injection of depot medroxyprogesterone acetate.
Although there is a small delay in the return of fertility, over
90
of women wil l have conceived by
24
months, which
i s
equivalent to women discontinuing other methods of
contraception. The delay in return of ferti lity is thought to
be due to slow metabolism of microcrystalline deposits in
muscle tissue.
E
t
onorgest eI re asing subd
e
r maI implant (Imp anon@)
70
71
72
reliably inhibits ovulation..................................... TRUE
has a Pearl Index of zero. TRUE
is
associated with an immediate return of fertility on
removal.................................................................. TRUE
Discussion
lmplanon is a highly effective method of contraception
and, a t the time of writing, there have been no
documented failures. It is the only form of contraception o
have a Pearl Index of zero. lmplanon i s associated wi th an
immediate return of fertility on removal.
Concerning intrauterine devices (IUDs),
73
a young nulliparous woman should be screened for
sexually transmitted infections prior to IUD insertion.
................................................................................
TRUE
74
they increase the likelihood of ectopic pregnancy.
.............................................................................. FALSE
75
there is a peak incidence of pelvic infection in the first
few weeks after insertion
....................................
TRUE
76 Levonorgestrel releasing
intrauterine system
(Mirenaq
is
associated with a higher risk of pelvic
infection than a copper IUD. .............................. FALSE
Discussion
An IUD is not associated with a significantly increased risk of
pelvic infection when used by women in monogamous
relationships wi th no risk factors for sexually transmitted
diseases. IUDs protect against all types of pregnancy,
including ectopic pregnancy. Although in the event of
failure of an IUD, the risk of ectopic pregnancy
is
higher
than in the normal population. Higher risk women such
as
young nulliparous women and those requesting a post-
coital IUD should be screened bacteriologically prior t o
insertion. There is a peak incidence of pelvic infection in the
first few weeks following insertion due to introduction of
organisms into the uterine cavity. Mirena may offer
additional protective benefit against the risk of pelvic
infection compared with copper IUDs, as a result of i ts
hormonal action.
A woman using a diaphragm and spermicide for
contraception
77
78 has an increased risk of having an infant with cleft
palate if the method fails.
..................................
FALSE
Discussion
Women using barrier methods of contraception have a
lower risk of pelvic infection. Although there was some
concern in the past about possible teratogenesis n women
using spermicide at the time of conception, recent scientific
data have been reassuring. There
i s
no evidence of
increased risk of congenital abnormality and use of
spermicide in the periconceptional period would not
represent grounds for therapeutic abortion.
The following statements are correct:
79 Inadvertent use of COC during early pregnancy
increases the risk of masculinsation of the female
fetus.
.....................................................................
FALSE
80 There i s no evidence to support the use of routine
antibiotic prophylaxis on insertion of IUDs
........
RUE
Discussion
Inadvertent use of COC during early pregnancy does not
increase the risk of masculinsation of female fetuses,
especially with modern low-dose preparations. There is no
evidence to support the use of routine antibiotic
prophylaxis on insertion of IUDs, although preinsertion
bacteriological screening may be appropriate in some
cases.
Fetal resuscitation in labour
With regard to caesarean section,
81 when performed for a cord prolapse
it
would be
classified as a grade three procedure ................ALSE
82
regional anaesthesia compared with a general
has a reduced risk of pelvic infection..................RUE
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Answers to Questions for Volume 4, Number 3
anaesthetic
is
associated wi th improved one-minute
Apgar scores.
......................................................... TRUE
there is strong evidence that a decision to delivery
interval of 30 minutes i s a critical threshold in
intrapartum fetal hypoxia
.................................. FALSE
Discussion
A caesarean performed for
a
cord prolapse
is
a
grade
1
caesarean as there i s an immediate threat to the l i fe of the
fetus. A regional anaesthetic
is
associated with
a
reduced
incidence of postoperative morbidity in the mother and
i s
also beneficial to the fetus, as it improves one-minute
Apgar scores.M However, in certain circumstances, such
as
during a persistent fetal bradycardia, there may not be
sufficient time to
site
a regional block. Evidence concerning
the 30-minute decision to delivery interval for emergency
caesarean sections
is
lacking.
Concerning maternal oxygen therapy,
84
83
a reservoir bag attached to a Hudson mask reduces
the fraction of effective inspired oxygen (FiO,).
.............................................................................. FALSE
85
the use of prolonged prophylactic oxygen in the
second stage of labour increases arterial cord blood
pH. ........................................................................
FALSE
86 fe ta l
brain tissue oxygenation
is
increased during
fifteen minutes
of
maternal oxygen therapy .....TRUE
Discussion
A reservoir bag increases the oxygen concentration the
mother inspires, as a t the middle of normal inspiration the
flow of air can be as high as 30 Vminute, which will not be
met by the flow of oxygen alone. Therefore, the patient
will breathe in the surrounding air. When prophylactic
oxygen was used in the second stage of labour, prolonged
use was associated with a significantly lower cord blood
P H . ~However, when oxygen therapy i s used for short
phases fetal brain tissue oxygenation
is
seen to increase
when measured by near-infrared spectroscopy.6
Concerning cord prolapse,
87 distending the bladder with saline has been
successfully used as part of the management of cord
prolapse................................................................. TRUE
88 in complete cord prolapse, funic replacement and
delayed delivery has been described wi th good fetal
outcomes.
.............................................................. TRUE
89 management regimes are guided by randomised
controlled clinical trials.
...................................... FALSE
Discussion
Although the traditional management for cord prolapse s
knee-chest position and immediate caesarean, both funic
replacementz8and distending the bladder have been
described.'6 There have been no randomised controlled
trials comparing different management regimens.
Concerning maternal position in labour,
90 measurement of maternal systemic blood pressure is
useful when assessing aortocaval compression.FALSE
91
a left-lateral position compared with
a
supine
position can improve
f e ta l
oxygen saturation by over
5 . ........................................................................
TRUE
Discussion
Kinsella et a/. demonstrated that aortic compression was
relieved by increasing the amount of tilt 12 This was
measured with toe pulse pressure. However, during the
compression there was no systemic hypotension. Fetal
oxygen saturation measured by oximetry shows a significant
decrease in mean fetal oxygen saturation from
53.2
in the
left-lateral position to 46.7 the supine p0siti0n.l~
With regard t o cardiotocographic (CTG) abnormalities and
the use
of
tocolytics in labour,
92
amniotic infusion may be used in selected cases in
labour t o treat some CTG abnormalities.............
TRUE
93 magnesium sulphate
i s a
less effective tocolytic in
labour than terbutaline.
....................................... TRUE
94 intravenous glyceryl trinitrate
is
a long-acting
tocolytic.
...............................................................
FALSE
95
intravenous terbutaline reduces uterine activity by
over
75
in
15
minutes .......................................
TRUE
96 adverse effects o f terbutaline include vomiting.TRUE
Discussion
Amniotic infusion has been shown to improve CTG
abnormalities and reduce the incidence of caesarean
sections, however, in these studies, fetal distress was not
confirmed by fetal blood ~arnpli ng.~agnesium sulphate
s
significantly less effective than terbutaline a t reducing
uterine activity. Glyceryl trinitrate has a short half life;
whereas terbutaline, as well
as
effectively reducing uterine
contractions, has
a
more prolonged action.lg Terbutaline
is
fast acting and can reduce uterine activity by up to 87.3 in
15
minutes. However, it can have significant adverse effects
including maternal tachycardia, palpitations, vomiting and
tremors.
With regard t o uterine activity in labour,
97
a uterine contraction of
1
kPa causes cessation of
placental bloodflow ............................................
FALSE
98 a
contraction interval of less than
two
minutes results
in a fal l of cerebral oxygenation. ........................ TRUE
99
the effects of a rapid infusion of normal saline on
uterine activity will last for
a t
least one hour. ..FALSE
100 fifteen minutes after ceasing an oxytocin infusion
there is approximately a 20 reduction in uterine
activity. ...................................................................
TRUE
.
Discussion
Uterine contraction above 4-6 kPa causes a cessation of
maternal intervillous placental bloodflow.16This produces
a
relative fetal hypoxia; recovery takes 60-90 seconds. A
short contraction interval of
less
than
two
minutes results
in a fall of cerebral oxygenation. The effects of a rapid
infusion
last
only
last 20
minutes. Stopping an oxytocin
infusion will not cause an immediate cessation of uterine
activity. After
15
minutes there
is
only a
22
reduction in
activity, by 30 minutes a 39 reduction and by 45 minutes
a 48 reducti~n.'~
A
clinical approach to heart disease in pregnancy
Part
1:
general considerations in man agem ent
Pregnancy is contraindicated in the following cardiac
conditions:
101 Eisenmenger's syndrome. .....................................
TRUE
102 severe asymptomatic aortic stenosis. TRUE
103 previous peripartum cardiomyopathy with residual
mild lef t ventricular dysfunction
......................... TRUE
104 mitral valve prolapse with severe mitral valve
Discussion
There are some common contraindications to pregnancy,
which have been well documented. These include severe
pulmonary hypertension, either primary or secondary, of
which Eisenmenger's syndrome is associated with up to
50 maternal mortality.' Any severe obstructive lesions,
whether they are symptomatic or not, are contraindicated
to pregnancy. Severe aortic stenosis
is
associated wi th
17
maternal mortality. Any minor decrease in preload or
increase in vascular volume
i s
detrimental. Surgical
regurgitation. FALSE
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Questions for Volume
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3
management
is,
therefore, advisable before pregnancy. '
Previous peripartum cardiomyopathy
i s
another
contraindication because of the high risk of recurrence and
overall poor prognosis.iv Regurgitant valve disease
is
well
tolerated in pregnancy because the systemic vasodilatation
favours
a
forward flow with an unimpeded lef t ventricular
filling.
Regarding heart disease in pregnancy,
105 evidence confirms that antibiotic regimens during
labour reduce the frequency of endocarditis.
...FALSE
106 valvular regurgitation carries a greater risk for the
mother than valvular stenosis.............................
FALSE
107 urinary tract infection
is a
significant risk factor for
the development of heart failure.
....................... TRUE
Discussion
There
is
no evidence to suggest that prophylactic antibiotic
regimens have an effect on the frequency of endocarditis.
Valvular stenosis carries
a
moderate to high risk of
mortality
(1-1
5 ) whereas mild t o moderate valvular
regurgitation carries
a
low risk (el
%).
Risk factors for heart
failure include anaemia, hypertension, multiple pregnancy
and infections, especially urinary tract infections.
The following statements
are
correct:
108 The use of angiotensin-converting enzyme (ACE)
inhibitors i s safe during pregnancy.
...................
FALSE
109 Paroxysmal nocturnal dyspnoea may be
a
normal
symptom of pregnancy....................................... FALSE
110 Cardiac output a t 24 weeks gestation is 45 greater
than in the non-pregnant state. .......................... TRUE
Discussion
ACE inhibitors should be avoided during pregnancy,
as
they are associated with
f e ta l
and neonatal renal failure
and death. While some symptoms such as palpitations can
be normal during pregnancy paroxysmal nocturnal
dyspnoea, synscope, haemoptysis and chest pain are not
and should be evaluated. Cardiac output increases in
pregnancy and by 24 weeks of gestation it rises to 45
above the baseline.
Additional references
i
Gleicher
N,
Midwall
J,
Hochberger D, Jaffin
H.
Eisenmenger's syndrome and pregnancy. Obstet
Gynecol Sun/ 1979;34:721-41.
ii Arias F Pineda J. Aortic stenosis and pregnancy. I
Reprod Med 1978;4:229-32.
iii
Oakley CM. Valvular disease in pregnancy.
Curr
Opin
Cardiol 1996;11:155-9.
iv. DeMarkis
JG,
Rahimtoola
SH.
Peripartum cardiomyo-
pathy. Circulation
1971;44:964-8.
v. Tang
LCH,
Chan S Y W Wong VCW, Ma HK. Pregnancy in
patients with mitral valve prolapse. lnt I Gynaecol
Obstet 1985;23:217-21.
Inte rpret ing statistics with confidence
A
95 confidence interval for the mean estimated from a
large random sample of observations
is
a set of values within which, in the long run, 95
of observations fall.
.............................................
FALSE
112
i s a
way of measuring the precision of the estimate of
the mean TRUE
113
is
an interval within which the sample mean falls with
probability 0.95................................................... FALSE
114 i s chosen so that 95 of such intervals will include the
population mean ..................................................
TRUE
115 can be calculated from mean minus 1.96 standard
errors to mean plus 1.96standard errors............
RUE
Discussion
The confidence interval for the mean does not te l l us
anything about the distribution or variability of the
observations. The sample mean
i s
always in the middle of
the limits. In large samples, sample estimate k1.96 tandard
errors
is
the usual way of calculating confidence intervals.
A
study
of
maternal depression was carried out in
Victoria,
Australia, in September 1993. he point
prevalence of depressiona t six t o seven months
postpartum was 16.9 (22511331; 5 C I 14.9 o 18.9 ).'
116 Another sample of the same
size
from this population
would have shown a rate of depression between
14.9 and 18.9
................................................. FALSE
117 95 of such women have a probability of between
14.9 and 18.9 of reporting depression........FALSE
118
It
is likely that between 14.9 and 18.9 of women
in the area would report depression
a t s ix
to seven
months postpartum.
............................................. TRUE
119 If the sample were increased to 2662 mothers, the
95
confidence interval would be narrower.
....TRUE
120
It
would be impossible o get these data if the rate for
all mothers in South Australia was
14 .
...........
FALSE
Discussion
The confidence interval i s an estimate of the overall
proportion, which applies to all women. It is the probability
that a woman chosena t random will have depression. We are
not estimating the distribution of risk. Ninety-five percent of
possible samples will have confidence intervals that contain
the population proportion, but this particular confidence
interval will not include95 of possible sample proportions.
A larger sample would result in a reduced standard error and
a narrower interval. A population proportion outside the
confidence interval
is
not impossible, as
5
of confidence
intervals do not include he population value.
In
a
randomised tr ial
of
vaginal clindamycin versus
placebo for early pregnancy bacterial vaginosis, the odds
ratio of preterm birth was
2 5
(95yo
C I
0.6
o
10.O).z
121 The odds ratio would be zero if the two treatments
had the same effect
............................................. FALSE
122 The treatments are not significantly different a t the
5
level. ................................................................ TRUE
Discussion
The odds ratio would be 1
O if
the treatment had no effect.
An odds ratio of zero would indicate
a
very large effect. As
the 95 confidence interval includes 1.0, he data are
consistent with the null hypothesis and the difference
is
not
significant.
In
a
trial of prednisolone versus placebo in children with
acute asthma, 2 of the
73
patients in the placebo group
were discharged
a t
first examination (3 ; 95
CI
1 t o
6 ).)Reported by Altn~an.~
123 This confidence interval i s plausible. FALSE
124 The exact binomial method should have been used
here........................................................................
TRUE
Discussion
The confidence interval should not include a negative
number, because the number of children discharged cannot
be negative. The large sample normal approximation t o the
binomial distribution has been used, but the sample is too
small. The exact binomial method would be much better,
giving 0.3 to 9.5 .
Children born during tw o randomised controlled trials of
routine ultrasound screening during pregnancy were
followed up
a t
ages eight to nine ears.A sample of
children underwent specific tes ts or dyslexia. The
t es t
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results classified 21
of
the 309 screened children (7 ;
95
C I
3
o
10 )
and
26
of the
294
controls
(9 ; 95 C I
4
o
12 )
as dyslexic.'
125
A confidence interval for the difference between the
percentages would be more useful than those given.
................................................................................ TRUE
126 A confidence interval for the ratio of the percentages
would be more useful than those given.
............
RUE
Discussion
Confidence intervals are always calculated regarding the
data as a sample. A sample of a sample is still a sample.
Much more useful would be
a
confidence interval which
compares the two groups directly. For the difference
between prevalences
it
would be 6.3 o +2.2 percentage
points, for the ratio
it
would be
0.44
o 1.34.
In a study of mitomycin in the treatment of non-small-cell
lung cancer, subjective response was reported complete in
two of 20 patients, reported as 10 ; 95 C I 0 o 21.6
127 The confidence interval should not include zero.
................................................................................ TRUE
Discussion
As we have observed a complete response in two patients,
it
i s impossible for the proportion in the population of
patients that includes them t o be zero.
Danish women having undergone h sterectomy with
from 1977 o 1981 (n
=
22 135)were compared with all
Danish women who had not undergone hysterectomy. The
extrapolated lifetime risk of developing ovarian cancer
was 2.1 after hysterectomy and 2.7 in the general
population
RR
0.78; 5
C I
0.60 o 0.96).'
128 If there were no difference, the expected relative risk
would be 1.0......................................................... TRUE
129
The difference
i s
statistically significant
.............
TRUE
Discussion
The null hypothesis value for a ratio is usually 1.0.As the
confidence interval does not include this, the difference
is
significant a t the 0.05 evel.
Salpingectomy and conservative tuba1 surgery as
treatments for ectopic pregnancy were compared
economically In the short term, costs per patient were
f1,554 (95 C I f1,501 o f1.656) or salpingectomy and
f1,787 (95 C I f1,683 o f1,930)or conservative
surgery.8
130 The different in cost between the two regimens is
statistically significant...........................................
TRUE
Discussion
The 95 confidence intervals do not overlap,
so
the
difference
i s
statistically significant. The authors also
correctly presented an estimate and confidence interval for
the difference in mean cost, f233 (95 CI f80 o 371).
conservation of a t least one ovary or a benign indication
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Obstetrician iynaecologist2002;4: 50)
Greentop Guideline 30: Managem ent
of
genital
herpes in pregnancy
The following statements are correct:
131
Most maternal herpes simplex virus (HSV) infections
are asymptomatic.................................................. TRUE
132 Lower segment caesarean section (LSCS) is
recommended for
al l
women presenting with
first-
episode genital herpes lesions during the second
trimester. .............................................................. FALSE
133
Antenatal swabbing accurately predicts the shedding
of virus a t the onset of labour ........................... FALSE
134 Almost all cases of neonatal herpes occur
as
a result of
postnatal transmission ........................................ FALSE
135 The incidence of neonatal herpes is less than two per
100000 live births annually in the
UK
.................
TRUE
136 Serological testing for HSV in late pregnancy i s cost
effective in preventing herpes related morbidity.
..............................................................................
FALSE
137 There i s no clinical evidence of fetal toxicity when
aciclovir i s administered t o the mother in late
pregnancy.
.............................................................
TRUE
138 Obtaining a history of genital herpes in the partner of
a woman i s not an accurate way of determining the
risk of acquiring primary HSV infection during
pregnancy. TRUE
139 Where genital herpes is present for the first time a t
the time of delivery, the risk of transmission to the
fetus
i s
dependant upon the time that the
membranes have been ruptured. ........................
TRUE
140
Routine performance of
LSCS
in cases of maternal
recurrent genital herpes lesions has led t o a
significant decline in the incidence of neonatal
herpes.
..................................................................
FALSE
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