Back to Basics!
The essence of
OBSTETRICS
in one hour
Karine J. Lortie , MD, FRCSC
Assistant Professor
Department of Ob/Gyn
The 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
Hormones
BhCG:
A subunit similar to TSH, LH, FSH
Measurable 8 days post conception
Role: stimulate CL
progesterone
100,000
Others use:
Zone 2000-6000
Level
• Mole
• Ectopic
• Ovarian cysts
5,000
8 days
8 weeks
16 weeks
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 care
Antepartum 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 Care
Optional 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
21 - 28
29 - 40
Average
4 kg
4 kg
4 kg
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
FGH
Q
JKLMNOP RST
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
crown rump length
Fetal heart: 7 wks
Limb buds:
8 wks
Morphology scan
18- 20 weeks
BPD
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 IUGR
Placental:
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
CARDIOTOCOGRAPHY
Maybe as good as BPP
1. Non-stress test:
movement
uterine activity
Oxytocin infusion
2. Stress tests:
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 decals
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 Treatment
1. 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
75
70
dbs
0
wks
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)
Classification (it changes all the time…)
Primary Diagnosis
Pre-existing hypertension
With comorbid conditions
With preeclampsia
(after 20 wks GA)
Gestational hypertension
With comorbid conditions
With preeclampsia
(after 20 wks GA)
Definition of preeclampsia
Resistant HTN, or new or
worsening ptnuria, or one/more
adverse conditions
New proteinuria, or one/more
adverse conditions
Eclampsia:
Convulsion during pregnancy or within 7 days to 6
weeks of delivery
Not caused by epilepsy
Risk factors
Primigravida 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
Twins
Diagnosis:
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 %
75 %
0-3
4-7
•
•
1%
<1 %
7 - 11
11+
Totally separate
Separate fetuses & amnion
single chorion with vascular
connections
Monoamniotic & monochorionic
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 dilatation
Latent 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
Nulliparas
All patients
Ideal Labor
Duration of first stage
(hr)
Latent phase
6.4(±5.1)
Active phase
4.6(±3.6)
Total
11.0(±8.7)
Maximum rate of
descent (cm/hr)
3.3(±2.3)
Duration of second
stage (hr)
1.1(±0.8)
Multiparas
All patients
Ideal labor
6.1 (±4.0)
3.4(±1.5)
9.5(±5.5)
4.8 (±4.9)
2.4(±2.2)
7.2(±7.1)
3.6(±1.9)
6.6(±4.0)
0.76(±0.5)
0.39(±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 Section
Indications
Failure to progress (Dystocia)
Repeat (Failed VBAC)
Fetal Distress
Breech Presentation
Placenta Previa
Cord prolapse
Abruption
Diabetes
Fetal 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: Etiology
Maternal:
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 disproportion
Relative disproportion
Massive baby! (macrosomia)
Passages
Diameters (pelvic anatomy)
Dystocia
Risk Factors:
age
Parity
Infection
Epidural
Position in labor
Induction
Macrosomia
cervix
Initial measure to treat dystocia
A. Attention to:
Comfort
wellbeing
hydration
B. Amniotomy
C. Oxytocin if A+B fail
D. Wait long enough to see a response
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 adequate
and 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