Obstetrics Flashcards
Physiologic changes associated with pregnancy?
CV - hyperdynamic circulation, reduced mean arterial BP (lowest 24wk), reduced PVR (vasodilation), reduced venous return and increased venous pressure (compression of IVC and pelvic veins by uterus)
Heme - hemodilution, increased WBC but reduced function (improve AI disease), reduced platelet #, hypercoagulable state
Resp - increased O2 needs, increased minute ventilation, diaphragm higher (reduced TLC, FRC, RV), RR same
Breasts - tenderness, increased size, increased vascularity, increased synthesis milk components, initiation secretory activity due to PRL and human placental lactogen, full lactation inhibited (E/P levels high)
Skin - increased pigmentation (increased melanocyte stimulating hormone), stretch marks (increased glucocorticoids)
GI - constipation, increased GERD, increased gallstones, hemorrhoids, n/v
Renal - increased GFR (increased blood flow), increased urinary frequency, increased UTI risk because stasis and glucose
Endocrine - increased size and vascularity of pituitary and thyroid glands, increased PRL, oxytocin, increased ACTH, increased GC secretion vs. normal TSH, increased thyroid hormones, increased BMR; suppressed GH replaced by hPL
Uterine - increased size of fundus via hypertrophy of stroma, pear -> globular shape -> spherical -> ovoid (cavity 4mL -> 5L); hypertrophy of blood vessels supplying uterus and dilation = increased blood flow
What infectious diseases to test for in preconception counselling?
HIV Rubella IgG Varicella Syphilis Hepatitis B Gonorrhea/chlamydia
What immunizations do you update in preconception counselling?
Hepatitis B Rubella Varicella Tdap (tetanus, diphtheria, pertussis) HPV Influenza
How much folic acid during preconception?
0.4-1mg OD 2-3mo preconception until end of T1 pr 5mg OD if family history of NTD, current hx IDDM, obesity, epilepsy, or hx poor compliance
What nutritional supplementation during preconception?
Folic acid
Iron –> 27mg/d for maintenance, 150-200mg/d to treat anemia
Prenatal multivitamin
Investigations for pregnancy workup?
CBC, blood group and type, sickle-cell status (if at risk), Rh status
Immune status (Rubella, Syphilis, HBsAg, HIV) -> antibody screen
Pap smear, chlamydia/gonorrhea/BV swabs
Urine R&M, C&S
What do you include in genetic screening counselling?
MSS
IPS
FTP
MFM if hx of infant with chromosomal abnormalities or abnormal screening tests
Timing prenatal visits?
First within 12wk LMP then
q4wk until GA 28wk
q2wk at 28-36 wk
q1wk at >36wk to delivery
When is dating US done?
GA 8-12wk
- measure of crown-rump length
- margin of error +/-5d
When do you assess CVS re: antenatal assessment?
10-12wk GA
When is FTS? IPS part 1?
GA 11-14wk
FTS = NTUS, b-hCG, PPAP-A; risk estimate for trisomy 21
- if + = CVS or amniocentesis should be offered
IPS 1 = NTUS + PPAP-A
What is done at 11-13 + 6 wk GA?
- NTUS -> measures AFV behind neck of fetus; early screen for congenital anomalies, i.e. trisomy 21 measures “thickness of neck”
- should be used alone for twin pregnancy estimation of T21 risk
- singleton pregnancy should have FTS, IPS, or QUAD screen
When is IPS part 2?
GA 15-18wk
- IPS part 2 MSS markers (e.g. QUAD screen)
When is QUAD screen done?
GA 15-20wk
- QUAD screen for trisomy 21, 18, and open NTDs
- > measures MSAFP, b-hCG, unconjugated E (E3/estriol), and inhibin-A
When is amniocentesis done?
GA 15-20wk if indicated
When is FMs (quickening)?
GA 18-22 wk to term
What is done at GA 18-22 wk?
US for
- anatomy and growth of fetus, margin of error +/-7d
- placenta position
- AFV (in obese women, US should be delayed until 21-22wk GA)
When do you screen for GDM?
Gestation diabetes screen at 24-28wk GA
- 50g oral glucose tolerance test
- plasma glucose <7.8 mmol/L = normal
- plasma glucose >7.8 to <10.3 mmol/L -> do 2h 75g OGTT
- plasma glucose >10.3 mmol/L -> GDM
Dx of IGT and/or GDM?
- both should be treated as GDM with increased surveillance, glucose monitoring and referral
1-2h 75g OGTT : 1 AbN = IGT, 2+ AbN = GDM
fasting plasma glucose >5.3 mmol/L
1h plasma glucose (75g OGTT) >10.6 mmol/L
2h plasma glucose (75g OGTT) >8.9 mmol/L
What do you do at GA 28wk?
Repeat CBC (Hg, Hct)
Check Rh - antibody titers
RhoGAM (RgIgG) for all Rh- women
When do you swab for GBS?
GA 35-37wk - vaginal and anorectal culture for GBS
Sx of pregnancy
amenorrhea n/v increased urinary frequency increased fatigue breast tenderness/ heaviness constipation lower abdo cramps backache/ headache
Chadwick sign
Blue cervix/vagina at 6wk
Goodell sign
Soft cervix at 4-6wk
Hegar sign
Soft uterine isthmus at 6-8wk
Normal FHR using doppler?
110-160 bpm
Size of uterus milestones?
symphysis at 12wk
umbilicus at 20wk
xiphoid process at 36wk
Naegele’s rule re: EDC
(LMP + 7d) - 3mo (for 28d menses cycle)
Leopold maneuvers
4 abdo palpations of gravid uterus to determine fetal lie, presentation and position
- first = what part of fetus occupies fundus (head = round, hard; buttocks = irregular)
- second = which side fetal back lies on (spine = long, linear, firm; extremities = multiple mobile small parts)
- third = presenting part of fetus (vertex (head) = round, firm vs. breech (sacrum) = irregular and nodular)
- fourth = position of fetal head (if intact in vertex position) by palpating cephalic prominence (flexed = brow most prominent on opposite side from fetal back; extended = occiput most prominent and felt on same side as spine)
Confirmation of pregnancy
b-hCG
- detected in serum 10d and urine 10-14d post-conception
- approx. 10IU at time of missed menses, 100,000 IU at 10wk and 10,000 IU at term
transvag US
- visible gestational sac at 5wk (b-hCG >1500-3000 IU), fetal pole at 6wk, and fetal heart beat by 6-7wk
transabdo US
- intrauterine pregnancy visible by 6-8wk (hCG >6500 IU)`
What is b-hCG
peptide hormone produced by trophoblast cells
maintains CL during pregnancy
Types of prenatal screening?
FTS = measures NTUS, PPAP-A, b-hCG
- estimates risk of trisomy 21 (85% sensitive if combo age)
QUAD = measures MSAFP + b-hCG + unconjugated E + inhibin A
- estimates risk of NTD, trisomy 21, trisomy 18
- NTD - increased MSAFP (80-90% sensitive)
- Trisomy 21 - decreased MSAFP, increased b-hCG, decreased unconj. E3, increased inhibin A (77% detection)
- Trisomy 18 - reduced MSAFP/b-hCG/unconj. E3/ inhibin A (75% detection)
IPS = combines QUAD screen markers + NTUS + PPAP-aA
- risk for trisomy 21, 18 and NTD
Prenatal Dx
Indications
- abnormal us
- abnormal prenatal screen
- PMHx or Fox genetic disease, chromosomal anomalies, recurrent pregnancy loss, consanguinity
Types
CVS - biopsy placental tissue
Amniocentesis - US-guided transabdominal extraction of amniotic fluid
Is influenza safe during pregnancy?
Yes
Required increased calories per day re: term?
T1 = 100kcal/d
T2 or T3 = 300 kcal/d
lactation = 450-500kcal/d
Important nutrients to supplement?
Ca - 1000mg/d
Vit D - 600 IU/d
Folate - 0.4-1 g/d
Fe2+ - 13-18 mg/d in T; 27 mg/d
Optimal wt gain re: pre-pregnancy BMI?
BMI <20 = 12.5 - 18 kg
BMI 20 - 27 = 11.5-16 kg
BMI >27 = 7-11.5kg
Risks of smoking during pregnancy?
- decreased O2 and nutrients to baby increased risk of - spontaneous abortion (1.2-1.8x) - abruptio placantae - placenta previa - preterm birth - low birth weight infant - SIDS
Complications EtOH while pregnant?
Teratogen -> freely crosses placenta and fetal BBB
- FAS -> growth retardation, facial abnormalities, CNS dysfunction
Unsafe meds during pregnancy (teratogenic)?
ACEI - IUGR, oligiohydramnios
Anticonvulsants - increased risk NTD
Lithium - Ebstein abnormality, goiter
Coumadin - warfarin embryopathy
Retinoids - CNS, CVS, craniofacial anomalies
Anti-sulfa drugs - NTD (T1), kerniecterus (if used >36wk)
Tetracycline - stains teeth
Chloramphenicol - grey baby syndrome
Fluoroquinolones - possible cartilage damage
Tx nausea/vomiting
Non-pharm - reduce spicy/greasy foods; eat dry crackers, small frequent meals
Pharm - IV/PO hydration if dehydrated (hyperemesis agravidarum)
- Diclectin
- nutritional supplement
UTI tx in pregnancy
Tx asx bacturia and uncomplicated UTI based on culture results
- common abx = amoxicillin, Nitrofurantoin
- -> avoid TMPSMX (esp T1 re: antifolate)
Complicated UTI or pyelonephritis - hospitalize and IV abx
- post-treatment urine culture and urine cultures qmonthly for rest of pregnancy
When do you offer membrane stripping?
38-41wk GA
Induction of labor when?
41-42 wk GA
What is amniotic fluid composed of?
Proteins, carbohydrates, electrolytes, fetal skin cells
- can be measured by US
Function of amniotic fluid?
- cushion fetus from external injury
- ensure proper MSK development
- develop fetal lungs and GI system
- maintain a constant temperature
Volume of amniotic fluid?
250 mL at 1wk GA
800mL at 34-36 wk GA
Ddx postdate pregnancy (>42 wk GA)
and increased risks
ddx - idiopathic; anencephaly (rare); placental sulfatase deficiency (rare)
increased risk:
- macrosomia
- post maturity syndrome
- oligohydramnios
- meconium aspiration
- asphyxia
- intrauterine infection
- placental insufficiency
- fetal distress
- dystocia
Oligohydranmnios
AFI <5th percentile for GA or <5cm at term
r/o PROM
AF usually decreases after 35wk
Dx - quantity AFV through US
- sterile speculum exam to r/o PROM
- fetal surveillance to identify IUGR or congenital anomalies (esp. renal/GU)
- idiopathic most common
Rx
- consult obs
- stop meds such as NSAIDs, ACE-I
- transient: maternal hydration
- frequent fetal surveillance
Indications to induce labor re: ogligohydranmnios
PPROM and >34wk GA
Idiopathic and >37-38wk GA
non-reassuring fetal testing
Polyhydranmnios
> 2000mL AF at any GA
95th percentile for GA
AFI >25cm at term
Dx
- quantify AFV through US
- US to identify multiple fetuses, fetal abnormality, fetal anemia
- GDM screening - 50g GDS if not done, or 2h OFT (75g) if normal 50g test
- +/- therapeutic amniocentesis
- idiopathic most common
(also maternal DM - preexisting and gestational)
Fetal kick counting - what is worrisome and fup?
- less than 6 movements in 2h = immediate further testing
- maternal and fetal assessment including NST +/- BPP
NST
classified as normal, atypical or abnormal
indication = decreased fetal movement
- normal and no risk factors for olio/IUGR = continue with kick counting
- normal and risk factors or suspected oligo/IUGR =BPP within 24h
- atypical or abnormal = urgent US
indication = pregnancies at high risk of adverse perinatal outcome
- if maternal and fetal status is stable, normal NST generally indicates favourable outcome for 1wk
- in IDDM or GDM or postdate pregnancy, frequent of NST is recommended 2x/wk
BPP`
indication - pregnancy at risk of adverse perinatal outcome
- abnormal results should be communicated to MRP immediately
- 8/10 to 10/10 with normal fluid, 8/8 with no NST = intervention for obstetric/ maternal factors
- 6/10 to 8/10 with low fluid = consult obstetrician
- 0/10 to 4/10 = immediate delivery required (consult)
Components of BPP
movement - >3 limb or body movements
tone - >1 flex/ext of limb or opening/ closing hand
breathing - >30sec
amniotic fluid - min 2x2cm pocket of cord/limb-free fluid
RF development of gestational HTN
- multiparty
- first pregnancy with new partner
- personal of FHx of HTN
- extremes of age
- multiple gestatoin
- obesity
- prev hx GHTN/preeclampsia
- medical disease (renal, DM, SLE, thrombophilia)
- abnormal pregnancy (molar/ partial mole)
Chronic vs. gestational HTN during pregnancy
Chronic - dx preceding pregnancy or dx GA <20wk
Gestational - dx >20wk GA
Define HTN
sBP >140mmHg or dBP >90mmHg on two occasions
- severe HTN = sBP >160mmHg +/- dBP >110mmHg
Define proteinuria
> 300mg/d protein on 24h urine collection or >30mg/ mmol random spot urinary protein/creatitine ratio
Define severe preeclampsia
Preeclampsia associated with any severe complication (warrants delivery at any GA)
Define preeclampsia (chronic vs gestational HTN)
chronic:
- resistant HTN (3+ meds to control BP)
- worsening or new proteinuria
- 1+ adverse condition
- 1+ severe complication
gestational:
- new proteinuria
- 1+ adverse condition
- 1+ severe complication
What are adverse conditions with preeclampsia?
- headache/ visual sx
- n/v
- RUQ/epigastric pain
- chest pain
- hypoxia
(maternal symptoms) - seizure
- severe HTN
- pulmonary edema
- placental abruption
(end organ dysfunction) - increased WBC/ INR/ PTT/ SCr
- increased liver enzymes
- decreased platelet <100, serum albumin <20
(abnormal labs) - abnormal FHR
- IUGR
- oligohydramnios
- absent or reversed end diastolic dopplers (umbilical)
(fetal complications)
etc
–> increased risk of severe complication
What are severe complications of preeclampsia?
necessitates immediate delivery - exclampsia - stroke/TIA - MI - cardioresp compromise - inotrope requirement - platelets <50 x 10^9 - need for transfusion - AKI - new indication for dialysis - hepatic dysfunctions - abruption - stillbirth etc
Investigations for HTN in pregnancy?
Maternal
- hematologic (CBC, blood film, PT/PTT, fibrinogen)
- liver function (ALT, AST, LDH, serum albumin)
- renal function (uric acid, Cr, analysis, 24h urine protein or spot protein/creatitine)
- imaging - consider CXR, liver US
Fetal
- NST
- US for fetal growth, fluid, BPP, umbilical artery Dopplers