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