Back to Basics!

The essence of

OBSTETRICS

in one hour

Karine J. Lortie , MD, FRCSCAssistant ProfessorDepartment of Ob/GynThe Ottawa Hospital/University of Ottawa

OVERVIEW

• Introduction• Early pregnancy• Antenatal care• Teratogens • Fetal growth and wellbeing• Medical complications• Breech• Multiple pregnancy • Labour

INTRODUCTION

RISK SPECTRUM IN PREGNANCY

LOW RISK (75%): normal obstetrics

MEDIUM RISK (20%): pre-post dates breech

twins maternal age, etc..

HIGH RISK (5%): genetic disease serious obstetric maternal complications

RISK IN PREGNANCY

Definition of Outcome Measures

1. Perinatal mortality rate• all stillbirths (intrauterine deaths) > 500

grams plus all neonatal deaths per 1,000 total births

2. Neonatal death• death of a live-born infant less than • 7 days after birth (early) or less than 28

days (late)

3. Live birth• an infant weighing 500 grams or more

exhibiting any sign of life after full expulsion, whether or not the cord has been cut and whether or not the placenta is still in place

PERINATAL MORTALITY

• Prematurity• Congenital anomaly• Sepsis• Abruption• Placental insuffienciency• Unexplained stillbirth• Birth asphyxia• Cord accident• Other ie. isoimmunization

PERINATAL MORTALITY RATE

• ONTARIO: 5/1000

• Developing: 100/1000

MATERNAL MORTALITY

• Direct Deaths• Indirect deaths: < 42 days from delivery

Causes:• Hypertensive disorders• Pulmonary embolism• Anesthesia• Ectopic pregnancy• Amniotic fluid embolus• Hemorrhage• Sepsis

MATERNAL MORTALITY RATE

• ONTARIO: 5/100 000

• Developing: 1000/100 000

EARLY PREGNANCY

EARLY PREGNANCY

Dating:40 weeks from LMP

280 days, Naegle’s rule (-3 months + 7 days)

Affected by cycle length

Hegar’s sign: soft uterus

Chadwicks sign: blue cervix

8 days 8 weeks 16 weeks

5,000

Level

100,000

doub

ling

time

2 d

ays

Others use:Zone 2000-6000

• Mole• Ectopic• Ovarian cysts

Hormones

BhCG:A subunit similar to TSH, LH, FSH

Measurable 8 days post conception

Role: stimulate CL progesterone

Other placental hormones

• HPL = human placental lactogen (growth hormone)

• prolactin

• progesterone

• estrogen

Which of the following statements best describes the foramen ovale:

1. It shunts blood from right to left

2. It connects the pulmonary artery with the aorta

3. It shunts deoxygenated blood into the left atrium

4. It is an extra cardiac shunt

5. It is functional after birth

ANTENATAL CARE

Maternal physiology

• RBC

• plasma volume by 50%, GFR, CrCl (creatinine), glucosuria

• cardiac output (highest 1st hour after delivery)

• HR by 20%

• SV

• Placental flow: 750ml/min at term

Antenatal careAntepartum history:

age: >40 offer amniocentesis

Parity/gravidity

Medical, surgical history

Family, social history

Meds, allergies

Routine tests:CBC (Hg), Type and Screen, prenatal antibodies

VDRL, Rubella, Hep B, HIV

Urine culture

Pap smear, + vag swabs, cervical cultures

Offer IPS

GBS swab at 35 weeks

Antenatal CareOptional testing:

Dating ultrasound, 18 weeks morphology ultrasound

Hb electrophoresis (Thalassemia, sickle cell, etc.)

Chicken pox, parvovirus, TSH

28 weeks glucose screening test

Genetic testing:CVS

Amniocentesis

Scheduled visits:0-28 weeks: q4 weeks

28-36 weeks: q2 weeks

36+ weeks: q1 week

Scheduled visits

SFH (cm): (+ 2 # of weeks)Sensitivity of 60%

12 weeks: symphysis pubis

20 weeks: umbilicus

36 weeks: siphisternum

presentation

Symptoms, fetal movement

+ urine dip: glucose, protein

Blood pressure, maternal weight

MATERNAL WEIGHT

wks gain

0 - 20 4 kg21 - 28 4 kg29 - 40 4 kgAverage 12 kg

• Underweight: 35-45 lbs• Normal BMI: 25-35 lbs• Overweight: less than 25 lbs

Genetic testing

IPS:First Trimester screening (10.6 – 13.6 weeks)

Nuchal translucency

PAPP-A, BhCG

Second Trimester screening (15-16 weeks)BhCG, estriol, AFP

94% detection rate

MSS:15-19 weeks

BhCG, estriol, AFP

70% detection rate

IPS vs MSS Detection rate

NT

Suchet I, Tam W. The ultrasound of life. Interactive fetal ultrasound teaching program on DVD, 4th Edition, 2004.

Screening patterns

Down’s syndrome: low AFP/estriol, high BhCG

Trisomy 18: low AFP, BhCG, estriol

Trisomy 13: high AFP, low BhCG/estriol

NTD: high AFP

All of the following factors are associated with an increased risk of perinatal morbidity except:

a) low socioeconomic status

b) low maternal age

c) heavy cigarette smoking

d) alcohol abuse

e) exercise

Appropriate screening tests in an early, uncomplicated pregnancy include all of the following except:

a) repeat BhCG

b) hemoglobin

c) syphilis serology

d) Cervical cytology

e) Blood type and Rh factor

TERATOGENS

I QF G H J K L M N O P R S T

Risk Classification System for Drug Use in Pregnancy 

Category Description

A Taken by a large number of pregnant women. No increase in malformation. 

B Taken by only a limited number of pregnant women and women of childbearing age. No increase in malformation. Studies in animals wither show no increase or are inadequate. C Have caused or may be suspected of causing harmful effects on the human foetus or neonate without causing malformations. These effects may be reversible. 

D Have caused an increased incidence of human foetal malformations or irreversible damage. 

X Drugs that have such a high risk of causing permanent damage to the foetus that they should not be used in pregnancy. 

 

FETAL GROWTH AND WELL-BEING

Dating Scan

Gestational sac: 5wks

Fetal pole: 6wks

Fetal heart: 7 wks

Limb buds: 8 wks

crown rump length

Morphology scan

18- 20 weeksBPD

HC

AC

Femur length

Info from U/S

• Estimated fetal weight

• Twins discordance

• Behavioral states (BPP)

• Presentation

• Placenta (previa)

Anomalies: ultrasound 18 - 20 weeks

• Spina Bifida• Anencephaly• Cardiac• Renal• Diaphragmatic hernia• Limbs • Facial• Chromosomal

Late > 20 weeks

• Renal• Microcephaly• Hydrocephalus• Ureteral valves

Interventions

• amniocentesis, l/s ratio (lung maturity)

• cvs

• cordocentesis, transfusion

• paracentesis

• Shunts: bladder, ascites, kidney, head

• Liver biopsy, skin

• Fetal reduction

DEFINITION OF I.U.G.R

• < than 2500 grams• < than 5th centile for GA• Approx. 4-7% of infants

BPD

AC

BPD

AC

CAUSES OF IUGR• Maternal:

• Malnutrition• Drugs• Substance Abuse• Diseases• Infections

• Fetal:• Chromosomal Abnormality• Congenital Abnormality• Multiple Gestation• Congenital Infection

CAUSES OF IUGRPlacental:

Perfusion

Abnormalities:Abnormal Cord Insertion

Abruption

Circumvallate placentation

Placental Hemangioma

Placental Infections

Twin to Twin Transfusion

IMMEDIATE NEONATAL MORBIDITY IN IUGR

• Birth asphyxia• Meconium aspiration• Hypoglycemia• Hypocalcemia• Hypothermia• Polycythemia, hyperviscosity• Thrombocytopenia• Pulmonary hemorrhage• Malformations• Sepsis

CAUSES OF FETAL OVERGROWTH

• Maternal diabetes

• Maternal obesity

• Excessive maternal weight gain

The perinatal mortality rate is defined as:

a) The number of neonatal deaths that occur per 1000 live births

b) The number of stillbirths that occur per 1000 births

c) The number of fetal deaths within the first week after birth

d) The number of stillbirths and neonatal deaths in the first week of life per 1000 live births

EVALUATION OF WELL-BEING

BIOPHYSICAL PROFILE• Graded (0 or 2 pts; max 10)

• NST (normal)• Movement (2)• Tone (2)• AFI (amniotic fluid volume)• Breathing (30 seconds)

DOPPLER• What is it?

• Uteroplacental waveforms• Umbilical artery• Carotid artery• Descending aorta

FETAL ACTIVITY

• Kick counts:• “count to ten “ chart• towards term• 10 movements in 2 hours over 12 hours

CARDIOTOCOGRAPHYMaybe as good as BPP

1. Non-stress test: movement

uterine activity

2. Stress tests:Oxytocin infusion

nipple stimulation

Features of the normal CTG:• rate 110-160 bpm• BTB variation 5-15 bpm• Accelerations present (2)• No decelerations (early, variable, late)

Which fetus to assess?

Small for gestational age, postdates

Maternal hypertension, diabetes

Antepartum hemorrhage

Decreased FM

The “high risk”pregnancy

Etc…

WHY FETAL ASSESSMENT?

1. ? To prevent damage (asphyxia)

2. ? To deter unnecessary intervention (prematurity,operative deliveries)

WHAT IS IT LOOKING FOR?

• Fetal hypoxia before asphyxia• Signs of placental failure:

• Poor fetal growth• Decr. FM• Decr. AFI• Atypical, abnormal NST

• How to test?• Fetal scalp pH sampling

• Normal >7.25• Borderline >7.21-7.25 (repeat sampling in ½ hour)• Abnormal <7.20 (deliver)

Criterias for asphyxia (hypoxic acidemia)

• umbilical cord arterial pH < 7.0

• base deficit > 16

• Apgar score 0-3 for >5 minutes

• neonatal neurologic sequelae (e.g. seizures, hypotonia, coma)

• evidence of multiorgan system dysfunction in the immediate neonatal period

NORMAL TRACE

Early decels

Late Decels

Variable Decels

Reduced Variability

Tachycardia

Characteristics or associated findings with late decelerations include all of the following except:

a) They may be seen in patients with pre-eclampsia

b) They may be associated with respiratory alkalosis

c) They are associated with a decreased uteroplacental blood flow

d) They often are accompanied by decreased PO2

e) They usually are accompanied by an increased PCO2

MEDICAL COMPLICATIONS

NAUSEA AND VOMITING

• Morning sickness: 50%• Hyperemesis gravidarum: 1%

• Tx: • Diclectin (10 mg doxylamine succinate with vit

B6)• Rest• Avoid triggers• Admit if severe (i.e. dehydration, electrolytes

imbalance)• TSH, LFT• IV• Dietitian consult• Psychology

DIABETES

Incidence: 1%

GDM: 3-5%Screening: 50g GTT

If > 7.8 do 75 g 2 hr OGTT

> 10.3 GDM

Risks factors:Previous stillbirth

Previous LGA

FHx

Persistent glycosuria

ORAL GLUCOSE TOLERANCE TEST (OGTT)

Criteria (ADA):• Fasting > 5.3• 1 hour > 10.0• 2 hour > 8.6

• 2 of the 3 values met or exceeded = GDM• 1 of the values failed = impaired glucose tolerance

Risks:• Anomalies• Infection• Pre-eclampsia• Macrosomia• Polyhydramnios• IUFD• shoulder dystocia

Rhesus isoimmunization

Incidence:7% african-american

13% caucasion

IgG anti-D in Rh –ve sensitized women

Can cause:fetal anemia

heart failure

Hydrops fetalis

Born with jaundice

In-Utero Dx: Amniocentesis, Cordo, Doppler

Prophylaxis: WinRho @ 28 wks + postpartum (newborn Rh status)

Antepartum hemorrage (>20 wks)

Causes:Placental abruption: concealed, revealed

Signs: vaginal bleeding, pain, fetal distress

Causes:PIH (DIC)

Cocaine

SLE

Smoking

Trauma

Previous abruption

Abnormal placentation: previa, vasa previa

Signs: painless vaginal bleeding

PPH

Causes (4T):1. Uterine aTony:

• Twins• long labor• Etc…

2. Tissue (Retained products)• Infection

3. Trauma (tears)4. Thrombin:

• Congenital Disorders• APH

PPH Treatment1. Conservative:

• Deliver the placental

• Bimanual compression

• Uterine packing

• IV, xmatch, blood bank (PRBC, FFP, …)

2. Medical:

• Ergot

• Hemabate

• Oxytocin

• cytotec

PPH Treatment

3. Surgical:

• Repair the tear

• D&C (explore the uterus)

• Ligate internal iliacs

• UAE

• B-Lynch suture

• Bachrey balloon

• Hysterectomy

HYPERTENSION

HYPERTENSION IN PREGNANCY

• Leading cause of maternal death and perinatal mortality/morbidity

• BP monitoring is major activity of antenatal care

• Affects up to 10 % of all pregnancies

TERMINOLOGY

dbs

wks

75

70

0 40

ABNORMAL VALUES? (depends on who…)• >140 / 90• DBP > 90 two readings• Systolic rise >30 or diastolic >15

PROTEINURIA>0.3 g/day (mild); >5 g/day (severe)

Primary Diagnosis Definition of preeclampsia

Pre-existing hypertensionWith comorbid conditionsWith preeclampsia (after 20 wks GA)

Gestational hypertensionWith comorbid conditionsWith preeclampsia(after 20 wks GA)

Resistant HTN, or new or worsening ptnuria, or one/more adverse conditions

New proteinuria, or one/more adverse conditions

Classification (it changes all the time…)

Eclampsia: Convulsion during pregnancy or within 7 days to 6 weeks of delivery

Not caused by epilepsy

Risk factorsPrimigravida or new partner

Age, race

Low social class

Familial trend ?single gene

Underlying hypertensive disorder 20 %

diabetes 50 %

Twins (mono) 30 %

Hydatidiform mole

Previous gestational hypertension 30 %

Severe:

• DBP> 110 with proteinuria (3-5g/d)

• Symptoms:• Headache• Scotomas• Epigastric pain/RUQ• Vomiting• Hyperreflexia

head ache

Management

MILD: monitor, deliver near term

SEVERE: stabilize and deliver

MOTHER: • Labwork: CBC, LFT, uric acid, BUN, Cr,

Albumin/creatinine ratio or 24 hour urine total protein, LDH, INR/PTT

• Symptoms: IV, meds, ….

BABY :• BPP• Ultrasound: growth, doppler• NST• Celestone, …

ANTIHYPERTENSIVES

• Short or long-term:• Methyl dopa• Labetolol• Nifedipine

• Acute:• Labetolol• Nifedipine• Hydralazine

ANTICONVULSANTS

• Prophylaxis and treatment:• Magnesium sulphate

ECLAMPSIA

• Rx:• Control airway• Stop convulsion• reduce BP• Deliver (C. Section?)• watch post natally

BREECH

ETIOLOGY OF BREECH PRESENTATION

• prematurity• Fetal abnormality• Multiple pregnancy• polyhydramnios• Placenta previa• Uterine abnormality

TYPES OF BREECH PRESENTATION

Extended (frank)

Flexed (complete)

incomplete

footling

MANAGEMENT OF BREECH PRESENTATION

• If diagnosed >34 weeks, options:• External cephalic version• Trial of labor with vaginal delivery• caesarean

Criteria for TOL:• At 37 - 38 weeks:

• Estimated fetal weight 2.5-4 kg• Frank or complete breech presentation• clinical pelvimetry adequate• Fetal abnormality excluded• No serious medical or obstetric complications

A complete breech presentation is best described by which of the following statements:

a) The legs and thighs of the fetus are flexed.

b) The legs are extended and the thighs are flexed.

c) The arms, legs, and thighs are completely flexed.

d) The legs and thighs are extended.

e) None of the above

TRANSVERSE LIE

• Incidence: 1:200 at term• Risk factors:

• Multigravidae• Placental previa• Fibroids• Polyhydramnios• Multiple pregnancy• Contracted pelvis• Fetal abnormality• Uterine abnormality

• Management:• Ultrasound• Cesarean if doesn’t turn

MULTIPLE PREGNANCY

Twins

• Incidence:• 1:80 (triplets 1:802)• 1:320 uniovular twins worldwide

• superfecundation• superfetation

• Etiology:• Population based• Age• Parity• Previous binovular twins• Heredity

TwinsDiagnosis:

LGA

u/s: lambda sign

Increased AFP

Management:Rest

Serial u/s

Assess presentation

+ IOL @ 38 wks

Placentation

Dizygotic:Separate amnion and chorion

Separate placentas

Presentation:Vx/Vx: 45%

Vx/BR: 25%

Br/Vx: 10%

Br/Br: 10%

Etc…..

Placentation

DIZYGOTIC DAY

• 23 % 0 - 3 Totally separate• 75 % 4 - 7 Separate fetuses & amnion

single chorion with vascularconnections

• 1% 7 - 11 Monoamniotic & monochorionic• <1 % 11+ conjoined twins

Hazards of multiple pregnancy

• Increased risk pre-eclampsia (X3)• pressure symptoms• anemia

• Abortion (disappearing sac)• Prematurity (approx. 30% deliver < 37/40 )• Polyhydramnios• twin-twin transfusion• Placenta previa• APH/PPH• Malpresentation• cord entanglement

cy cy

LABOR

What is Labor ?

(: work)

Regular painful uterine contractions

accompanied by progressive effacement and

dilatation of the cervix.

Timing of Labor

• 40 weeks

• 8% deliver on E.D.C.

• 7% premature <37 weeks

• 10% post-mature >42 weeks

Signs of Onset of Labour

• “Show”

• Rupture of membranes

• Contractions

Detection of ruptured membranes

• Nitrazine Test:

• Alkaline pH of fluid turns blue

• Ferning:

• High Na+ content causes “ferning” on

air dried slide

Ferning

Cord prolapse

Only with ruptured membranes

Incidence: 1/300

Risk factors:80% happen in multigravida

Malpresentation:Transverse lie

Breech

High head

Twins

Prematurity

OB interference: forcep, arm

Cord prolapse

• Diagnosis:• Ultrasound• Pelvic exam in labour (e.g. after ROM)• FHR abnormality

• Treatment:• Don’t panic• Push up presenting part• Sims position or knee/chest• Cesarean (forceps if fully)

Stages of Labor

1st stage: Onset to ‘full dilatationLatent and active

2nd stage: Full dilatation to delivery of baby

3rd stage: Delivery of placenta

4th stage: Placenta to 6 wks PP

Table 30-1. Characteristics of Labor Nulliparas and Multiparas*

Characteristic All patients Ideal Labor All patients Ideal laborNulliparas Multiparas

Duration of first stage(hr)Latent phase 6.4(±5.1) 6.1 (±4.0) 4.8 (±4.9) 4.5 (±4.2)Active phase 4.6(±3.6) 3.4(±1.5) 2.4(±2.2) 2.1 (±2.0)Total 11.0(±8.7) 9.5(±5.5) 7.2(±7.1) 6.6(±6.2)

Maximum rate of descent (cm/hr) 3.3(±2.3) 3.6(±1.9) 6.6(±4.0) 7.0(±3.2)Duration of secondstage (hr) 1.1(±0.8) 0.76(±0.5) 0.39(±0.3) 0.32(±0.3)

* All values given are ± SD.

(Data from Friedman EA: Labor: Clinical Evaluation and Management. 2nd ed. New York, Appleton-Century-Crofts, 1978).

Cesarean SectionIndications

Failure to progress (Dystocia)Repeat (Failed VBAC)Fetal DistressBreech PresentationPlacenta PreviaCord prolapseAbruptionDiabetesFetal Reasons (e.g. prevent infection)Social...

Premature labor

Incidence: 7% <37 wks

Major cause of perinatal morbidity

Overall recurrence risk of 30%

Risk factors:Previous PTD

Smoking

Low income

Cervical surgery

Uterine anomaly

Multiple pregnancy

Premature labor

Treatment:Rest

Steroids (for fetal lung maturity)

Tocolytics?

PPROM:Mercer protocol (IV/PO ampicillin(amoxil)/erythromycin)

Prevention:Ultrasound cervical length?

Fetal fibronectin (predictor?)

Amniotic Fluid• Mainly fetal urine• Some from extraplacental membranes

• 12 wks: 50 mls• 24 wks: 500 mls• 36 wks: 1,000 mls

• Oligohydramnios:• Reduced AFI on u/s: <5cm • SFH: small for dates; baby easy to feel• Causes:

• Placental insufficiency• Urinary tract dysplasia

• Diagnosis:• Ultrasound

• Treatment:• Intensive monitoring• Early delivery

Polyhydramnios

• Definition:• An excess of liquor to such a degree that it is

likely to influence the course or management of pregnancy.

• >20 cm

• Diagnosis:• SFH increased: large for dates• Tense and uncomfortable• Fluid thrill• Difficult to feel fetus

Polyhydramnios: EtiologyMaternal:

Multip

Diabetes

GHTN

Infection: toxoplasmosis, CMV

Fetal:Macrosomia

Anencephaly, hydrocephaly

Gut atresia

Multiple pregnancy

CAN’T SWALLOW (diaphragmatic hernia, mediastinal tumor)

HYDROPS FETALIS (Rh incompatibility, infection, heart disease, thalassemia major, etc.)

Dystocia

Definition:Abnormal progression of labour in the ACTIVE Phase

Cervical dilatation of <0.5 cm/hr over a 4 hr period

arrest of progress in the ACTIVE phase either in the first or second stage of labour

Failure of descent of presenting part

Friedman’s curve

CAUSES OF DYSTOCIA

Power Uncoordinated uterine action Dysfunctional Labour

Passenger Cephalo-pelvic disproportionRelative disproportionMassive baby! (macrosomia)

Passages Diameters (pelvic anatomy)

Dystocia

Risk Factors:age

Parity

Infection

Epidural

Position in labor

Induction

Macrosomia

cervix

Initial measure to treat dystocia

Comfortwellbeinghydration

B. Amniotomy

C. Oxytocin if A+B fail

D. Wait long enough to see a response

A. Attention to:

Oxytocin usage

• Dosage:• Depends on your hospital protocol• Initial dose: 1 to 2 mu/min• Rate increased by 1 to 2 mu/min every 30 min

until contractions are considered adequateand cervical dilatation achieved

• Clinical response usually seen at dose levels of 8-10 mu/min

Reduction of risk of dystocia

Avoid induction for large fetal weight

Avoid oxytocin use with unfavourable cervix

Avoid admission to Labour and Delivery at <4cm dilatation

“Management” of epidural at full dilatation

Avoid immediate pushing after full dilatation

Supportive strategies

Cervical evaluation for ripening prior to booking induction

Obstetrical triage

Continuous professional support in active labour

Mobilization of women in active labour

Minimization of motor blockage with epidural

Use of amniotomy and oxytocin prior to C/S for dystocia

Cesarean section for dystocia

Timing of procedure Rate

Latent phase 41%

Active phase 38%

Second stage 21%

Source: Stewart CMAJ 1990:142; 459-463

Appropriate management for slow labour (dystocia) associated with an occiput posterior presentation during the first ACTIVE stage of labour would include:

a) immediate cesarean section

b) forceps

c) augmentation with oxytocin

d) external cephalic version

e) fetal blood sampling