Download - OB Prolonged Pregnancy
Prolonged PregnancyProlonged Pregnancy(Evidence Based)(Evidence Based)
Prolonged PregnancyProlonged Pregnancy(Evidence Based)(Evidence Based)
Dr. Ashraf FoudaDr. Ashraf Fouda
Ob./Gyn. ConsultantOb./Gyn. Consultant
Damietta Specialized Damietta Specialized HospitalHospital
SourcesSources
RCOG 2003RCOG 2003
ACOG (ACOG (SEPTEMBER 2004)
COCHRANE LIBRARY 2006COCHRANE LIBRARY 2006
AFP (AMERICAN FAMILY AFP (AMERICAN FAMILY
PHYSICIAN) (May 15, 2005) PHYSICIAN) (May 15, 2005)
PUBMED (MEDLINE)PUBMED (MEDLINE)
Prolonged pregnancy Prolonged pregnancy
( ( postterm pregnancy )postterm pregnancy ) It It
is one that has lasted longer than 42 is one that has lasted longer than 42
weeks or 294 days beyond the first weeks or 294 days beyond the first
day of the last menstrual period day of the last menstrual period
DEFINITIONDEFINITION
( (WHO & FIGOWHO & FIGO) )
PostdatismPostdatism is pregnancy lasting is pregnancy lasting
beyond the estimated due date at beyond the estimated due date at
40 weeks. 40 weeks.
““Postmature”Postmature” is reserved for the is reserved for the
pathologic syndrome in which the pathologic syndrome in which the
fetus experiences fetus experiences placental placental
insufficiencyinsufficiency and resultant and resultant IUGR .IUGR .
DEFINITIONDEFINITION
Representing Representing 20 % cases 20 % cases of prolonged of prolonged pregnancy and is associated with :pregnancy and is associated with :
1.1. Meconium -stained amniotic fluid, Meconium -stained amniotic fluid,
2.2. Oligohydramnios Oligohydramnios
3.3. Fetal distress Fetal distress
4.4. Evidence of loss of subcutaneous fat Evidence of loss of subcutaneous fat andand
5.5. Dry, cracked skinDry, cracked skin
Reflecting placental insufficiency.Reflecting placental insufficiency.
Post-maturity syndromePost-maturity syndrome
Etiologic FactorsEtiologic Factors The most frequent cause is an
error in dating.
When truly exists, the cause usually
is unknown.
Primiparity and prior postterm
pregnancy are the most common
identifiable risk factors.
Etiologic FactorsEtiologic Factors
Rarely, it may be associated with
placental sulfatase deficiency or fetal
anencephaly.
Male sex also has been associated.
Genetic predisposition may play a
role .
Using the definition of Using the definition of 294 days294 days, ,
the the incidence ofincidence of
postterm pregnancy is postterm pregnancy is 9 - 10 %. 9 - 10 %.
EPIDEMIOLOGYEPIDEMIOLOGY
Risks to the FetusRisks to the Fetus
The perinatal mortality:
> 42 weeks twice that at term
> 43 weeks > 6-fold that at term
In some cases, the risks appear to be due In some cases, the risks appear to be due to to uteroplacental insufficiencyuteroplacental insufficiency, , resulting in resulting in fetal hypoxiafetal hypoxia , , meconium meconium aspirationaspiration, , growth restrictiongrowth restriction, and , and oligohydramniosoligohydramnios . .
Fetal distress and meconiumFetal distress and meconium release release were were twicetwice as common (at or after 42 as common (at or after 42 weeks) than at term. weeks) than at term.
There was anThere was an eight-fold eight-fold increase in increase in meconium aspiration meconium aspiration
Risks to the FetusRisks to the Fetus
- In other cases, continued growth of the - In other cases, continued growth of the
fetus leads tofetus leads to macrosomiamacrosomia, ,
increasing the risk of increasing the risk of
labor abnormalitieslabor abnormalities, , shoulder shoulder
dystocia dystocia with resultant risks of
orthopedic or neurologic injury.
- Macrosomia is far more common in - Macrosomia is far more common in
postterm than term pregnancies . postterm than term pregnancies .
MacrosomiaMacrosomia
OligohydramniosOligohydramnios
It is a marker for It is a marker for fetal compromisefetal compromise and it and it
puts the puts the fetus at risk for cord accidentsfetus at risk for cord accidents..
U/S diagnosis :U/S diagnosis :
No vertical pocket > 2 cm orNo vertical pocket > 2 cm or
Amniotic fluid index (AFI) 5 cm or lessAmniotic fluid index (AFI) 5 cm or less . .
It is considered an indication for delivery.It is considered an indication for delivery.
Fetuses born postterm also are at increased
risk of : Sudden
infant death syndrome
(death within the first year of life).
Some of these deaths clearly result from
peripartum complications
(such as meconium aspiration syndrome),
but most have no known cause.
Risks to the FetusRisks to the Fetus
Maternal risksMaternal risks
1) Labor dystocia
2) Severe perineal injury
related to macrosomia
3) Doubling in the rate of cesarean
delivery.
4) A source of extreme anxiety for
the pregnant woman.
Gest. age must be assessed carefully Gest. age must be assessed carefully
to avoid delivery of a preterm infant.to avoid delivery of a preterm infant.
Women who Women who attend lateattend late for ANC may for ANC may
be of uncertain gestation and may be be of uncertain gestation and may be
over-represented in populations of over-represented in populations of
postterm pregnancies.postterm pregnancies.
Dating by the last menstrual period (LMP) Dating by the last menstrual period (LMP)
alonealone has a tendency to has a tendency to overestimateoverestimate
the gestational age. the gestational age.
Gestational age calculationGestational age calculation
Gestational age calculationGestational age calculation Because actual dates of conception are Because actual dates of conception are
rarely known, therarely known, the
LMPLMP is used as the reference point. is used as the reference point.
This can make the accuracy of gest. age This can make the accuracy of gest. age
determination determination unreliableunreliable because of :because of :
1.1. Irregular menses .Irregular menses .
2.2. Recent cessation of birth control pills.Recent cessation of birth control pills.
3.3. Inconsistent ovulation times.Inconsistent ovulation times.
Routine early pregnancy Routine early pregnancy
ultrasoundultrasound♣ Reduces the number of women who
require induction of labour for apparent
postterm pregnancy .♣ It is recommended that all pregnant
ladies (and certainly those who do not
have regular menses), should have an
ultrasound examination for gestational
age determination, prior to 20 weeks
RCOG,COCHRANE
Crown-rump length Crown-rump length (CRL) (CRL) till till 1212 weeks is weeks is 3-5 days,3-5 days,
Biparietal diameter (BPD) Biparietal diameter (BPD) atat 12-2012-20 weeks weeks is is 1 week1 week, ,
BPD BPD at at 20-30 20-30 weeksweeks is is 2 weeks2 weeks, and , and BPD BPD after after 30 weeks30 weeks is is 3 weeks3 weeks.. If there is more than a one week
discrepancy between the LMP and the ultrasound findings, the ultrasound data should be used to determine the EDD .
Ultrasound biometry margins of error
Transcerebellar diameter When When composite biometrycomposite biometry is not is not
consistent in all of the parameters consistent in all of the parameters (i.e. (i.e.
BPD, head circumference, abdominal BPD, head circumference, abdominal
circumference, femur length),circumference, femur length),
using the using the transcerebellar diameter transcerebellar diameter is a is a
way to more accurately date a pregnancy way to more accurately date a pregnancy
The diameter in The diameter in millimeters corresponds millimeters corresponds
to weeks of to weeks of
gestation up to 24 weeks.gestation up to 24 weeks.
Transcerebellar diameter
The available evidences are The available evidences are
strongly in support that strongly in support that dating dating
by by Early Early
ultrasonographyultrasonography alone alone
is the most is the most
accurate method for predicting accurate method for predicting
EDDEDD. . RCOG (GRADE A)
The use of The use of early ultra sound early ultra sound alonealone to to
calculate the rate of postterm calculate the rate of postterm
pregnancy in women who delivered pregnancy in women who delivered
spontaneously significantly spontaneously significantly
reduced the postterm rate reduced the postterm rate
from 10 % to 1.5 %.from 10 % to 1.5 %.
Routine early pregnancy Routine early pregnancy ultrasoundultrasound
RCOG (GRADE A)
Are there interventions that decrease Are there interventions that decrease the rate of postterm pregnancythe rate of postterm pregnancy??
Accurate dating on the basis of ultrasonography performed early in pregnancy .
Breast and nipple stimulation at term have not been shown to affect the incidence of postterm pregnancy.
Sweeping of the membranes at term : the data are still conflicting .
ACOG Guidelines 2004
1) Gestational age,
2) Absence/presence of maternal risk factors
and / or
3) Evidence of fetal compromise, and
4) Maternal preferences .
Successful management depends on Successful management depends on
effective counselling of womeneffective counselling of women
and their full involvement in the and their full involvement in the
decision making process.decision making process.
Management options depend on:Management options depend on:
a.a. Inducing labour at 41-42 weeks Inducing labour at 41-42 weeks
gestationgestation or or
b.b. Awaiting the onset of spontaneous Awaiting the onset of spontaneous
labour, while monitoring the fetal labour, while monitoring the fetal
wellbeing .wellbeing .
The decision is difficult and should The decision is difficult and should
not be taken lightly.not be taken lightly.
Historically, prolonged pregnancy has Historically, prolonged pregnancy has
been managed in 2 ways , either :been managed in 2 ways , either :
Routine induction of labour Routine induction of labour at 41 weeksat 41 weeks
Although postterm pregnancy is defined
as a pregnancy of 42 weeks or more of
gestation, several large multicenter
randomized studies reported favorable
outcomes with routine induction as early
as the beginning of 41 weeks of
gestation.
Cochrane 2006
A recent review in the Cochrane Library A recent review in the Cochrane Library concluded that concluded that
routine induction in low-risk routine induction in low-risk pregnancies at or after 41 weeks' pregnancies at or after 41 weeks'
gestationgestation is associated with : is associated with :
1.1. A reduction in perinatal mortality,A reduction in perinatal mortality,
2.2. No increase in the rate of instrumental No increase in the rate of instrumental or cesarean delivery. or cesarean delivery.
RCOG Grade ARCOG Grade A
Routine induction of labour Routine induction of labour at 41 weeks at 41 weeks
Contrary to what many obstetricians believe, Contrary to what many obstetricians believe,
induction of labor for prolonged pregnancy induction of labor for prolonged pregnancy
does not increase the rate of cesarean does not increase the rate of cesarean
sectionsection, rather, it decreases it., rather, it decreases it.
The risk of The risk of fetal distressfetal distress from uteroplacental from uteroplacental
insufficiency due to prolonged pregnancy insufficiency due to prolonged pregnancy
can be reduced by induction of laborcan be reduced by induction of labor, even to , even to
the point of preventing perinatal death from the point of preventing perinatal death from
asphyxia. asphyxia.
Routine induction of labour Routine induction of labour at 41 weeksat 41 weeks
There is insufficient evidence to indicate
whether routine antenatal surveillance
of low-risk patients between
40 and 42 weeks of gestation
improves perinatal outcome
but it is
often performed during this period.
ANTEPARTUM FETAL ANTEPARTUM FETAL SURVEILLANCESURVEILLANCE
The The condition of the fetus can change condition of the fetus can change
quicklyquickly and thus, monitoring should be and thus, monitoring should be at at
frequent intervalsfrequent intervals, and that none of , and that none of
the tests are immune from false the tests are immune from false
positives, false negativespositives, false negatives
Boehm et al, demonstrated that Boehm et al, demonstrated that twice-twice-
weeklyweekly testing of patients at risk for fetal testing of patients at risk for fetal
distress was distress was superior to weekly testingsuperior to weekly testing. .
ANTEPARTUM FETAL SURVEILLANCE ANTEPARTUM FETAL SURVEILLANCE
A A modified biophysical profilemodified biophysical profile
consisting of a: consisting of a:
non stress test and an non stress test and an
amniotic fluid indexamniotic fluid index
have been shown to be have been shown to be
as sensitive as a as sensitive as a full biophysical full biophysical
profileprofile. .
FETAL SURVEILLANCEFETAL SURVEILLANCE
RCOG Grade ARCOG Grade A
Favorable cervixFavorable cervix : : Labor generally is induced because the risk of failed induction and subsequent cesarean delivery is low.
Unfavorable cervixUnfavorable cervix : :a small advantage to labor induction using cervical ripening agents (prostaglandins), when indicated, regardless of parity or method of induction.
Induction of labour or Induction of labour or expectant management?expectant management?
ACOG 2004 ACOG 2004 (Level C)
A .Healthy, uncomplicated pregnancy and
fetal growth/ amniotic fluid normal:
No evidence to support elective
induction of labour
No evidence to support use of serial
antenatal monitoring :
non stress test (NST) or
amniotic fluid index (AFI) .
Management from 40Management from 40-41-41 weeks weeks gestationgestation
B. Presence of maternal risk factors or
evidence of fetal compromise :
Recommend cervical ripening
as necessary and
induction of labour
Management at 40 Management at 40 - 41- 41 weeks weeks gestationgestation
A. Healthy, uncomplicated pregnancy
Inform the woman of the options and
risks/ benefits of labour induction versus
expectant management, and
offer her labour induction.
Establish the cervical (Bishop) Score and
ensure a ripening agent (prostaglandin)
prior to induction.
Management at 41 weeks Management at 41 weeks gestationgestation
B. If mother declines induction , then provide expectant management:
Daily fetal movement counts
Non stress test (NST) and Amniotic fluid index (AFI) twice/ week to 42 weeks.
If the NST or AFI is abnormal , then initiate induction immediately
Management at 41 weeks Management at 41 weeks
gestationgestation
Induce at 42 weeks Induce at 42 weeks even if NST and AFI are normal.even if NST and AFI are normal.
۞ Consider amniotomy to diagnose thick
meconium.
۞ If meconium is present then consider risk
of meconium aspiration , continuous fetal
assessment with electronic fetal monitoring
(EFM) is recommended.
۞ Be prepared for shoulder dystocia and
neonatal resuscitation at delivery.
Management during labour and Management during labour and
deliverydelivery
Labour induction at 41 weeks
gestation is recommended over
expectant management in women
with postterm pregnancy to reduce
the rate of cesarean delivery &
perinatal mortality .
Key Clinical RecommendationsKey Clinical Recommendations
(RCOG Grade A)
If Expectant management (41-
42 weeks) is chosen, the
fetus should be monitored with
twice weekly non-stress test ,
amniotic fluid index .
- However, evidence of benefit
is lacking.
Key Clinical RecommendationsKey Clinical Recommendations
(RCOG Grade C )
Prostaglandin can be used in postterm
pregnancies to promote cervical ripening
and induce labor.
Delivery should be effected if there is
evidence of :
fetal compromise or
oligohydramnios.ACOG 2004 ACOG 2004 (Level A)
Key Clinical RecommendationsKey Clinical Recommendations