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
Management HTN pregnancy?
Target BP 130/80 to 155/105 if no comorbidities
antihypertensives: methyldopa, beta blockers (labetolol first line), nifedipine, hydralazine (emergency only)
hospitalize if BP >160/110 or adverse features (obs consult)
outpt management
- weekly fup, weekly labs and US
- daily BP
delivery
- IOL at >37wk if preeclampsia or GHTN
Complications of ACEI in pregnancy?
- cranium malformation
- renal failure
- renal agenesis
- oligohydramnios
- fetal contractures
- IUGR
- IUFD
Elevated blood sugars when pregnant increases risk for what?
- polyhydramnios
- fetal macrosomnia
- preeclampsia
- operative delivery
- birth trauma
- neonatal hypoglycaemia
Classify diabetes in pregnancy
Preexisting (type 1 or 2)
GDM (onset of DM during pregnancy)
- often dx in late gestation (T2)
- if dx <24wk it is likely un-dx type 2 (order A1C)
RF for GDM
- prev hx GDM or glucose intolerance
- FHx diabetes
- prev. macrosomnia (>4000g)
- prev. unexplained stillbirth
- prev. neonatal hypoglycaemia, hypocalcemia, or hyperbilirubinemia
- advanced maternal age
- obesity
- repeated glycosuria in pregnancy
- polyhydramnios
- suspected macrosomnia
Diagnosis of GDM
- screening: 1h 50g oral glucose challenge test
at 24-28wk GA (unless hx GDM, fetal macrosomnia, Fox DM, obesity, PCOS then 14-20wk and repeat 24-28wk if negative)
–> glucose <7.8 = normal
–> glucose 7.8-11.1 = 75g 2h OGTT
–> >11.1 = GDM
2h 75g OGTT
- fasting plasma glucose >5.3
- 1h plasma glucose >10.6
- 2h plasma glucose >9
- -> GDM diagnosis
Management GDM
Strict glycemic control
- diet control, exercise -> maintenance of healthy consistent activity level as long as no CI
- insulin therapy -> initiate if blood glucose not well controlled on lifestyle modification alone
Fetal surveillance
- FM counts (6 movements in 2h)
- US to assess fetal growth/size at 36-39wk
- if on insulin -> twice weekly NST and BPP from 32wk until delivery
Delivery
- recommended delivery by 41wk to all GDM, and by 39wk to IDGDM
- if EFW >4.5 kg -> c/s recommended
Postpartum (r/o persistent DM)
- follow up fasting plasma glucose + 2h 75g OGTT at 6-12 wk postpartum (for mothers with post delivery fasting glucose >7)
Maternal complications in DM
Obstetric
- preeclampsia
- increased risk of c/s, birth trauma, operative delivery, spontaneous abortion (if preexisting DM), PTL (associated with polyhydramnios), infection (asymptomatic bacteria, pyelonephritis, vulvovaginitis, resp infections)
- polyhydramnios
Metabolic: increased risk of
- DKA (preexisiting DM)
- severe hemorrhage
Worsening microvascular disease (in preexisting DM):
- CAD
- retinopathy
- HTN
- nephropathy
- neuropathy
- retinopathy
Postpartum
- increased risk of infection
Long-term
- recurrence of GDM in future pregnancies
- development of T2DM in women with GDM in pregnancy
Fetal complications of GDM
Growth
- macrosomnia
- IUGR (preexisting DM)
- intrauterine fetal demise (IUFD)
Increased risk of structural malformations (preexisting DM with elevated A1C at conception)
- congenital heart defects
- NTD
- skeletal defects
Neonatal sequelae
- RDS
- hypoglycemia
- hyperbilirubinemia/ jaudice
- hypocalcemia
- polycythemia
Long term
- increased risk of obesity
- increased risk of T2DM
Prelabor rupture of membranes (PROM) definition
- spontaneous rupture of minion and chorion before onset of labor
Define latency period re: PROM
- time between ROM and onset of labor
Prolonged PROM definition
> 24h between ROM and labor onset
Preterm ROM definition
ROM before 37wk GA
Preterm PROM (PPROM) definition
ROM before 37wk GA and before onset of labor
RF PROM
Maternal
- infection (UTI, STI, cervicitis, vaginitis, intrauterine)
- hx PTL or PPROM
- cervical insufficiency or hx cervical surgery
- trauma
- smoking
- low SES, poor nutrition
Fetal
- multiple gestations
- polyhydramnios
Pregnancy
- amniocentesis
- chronic abruption, antepartum hemorrhage (APH)
- cerclage in current pregnancy
How do you confirm rupture of membranes?
Sterile speculum exam
- pooling amniotic fluid in posterior fornix and fluid leaking from cervix during cough/ valsalva
- Nitrazine test (amniotic fluid turns nitrazine paper blue)
NO cervical exam (avoid introducing infection)
PROM prognosis
spontaneous labor within 1 wk
- approx 50% women <26wk GA
- approx 85% women 28-34wk GA
complications
- chorioamnionitis
- cord prolapse
- premature delivery
- limb contracture
Lab investigations re: PROM
- CBC
- u/a
- urine C&S
- cervical culture for G&C
- anovaginal swab for GBS status
Management PROM without signs of fetal distress, placenta abruption or chorioamnionitis (or labor)?
<34wk = conservative management (risk of prematurity outweighs risk of neonatal sepsis)
- limited/light activity
- continuous FHR monitoring until stable then q8h
- daily NST and biweekly BPP
- antibiotics (GBS prophylaxis if in labor = Pen G; no labor = ampicillin + erythromycin IV x2d then PO x5d)
- antenatal steroids if not already had in pregnancy - betamethasone 12mg IM q24h x2
> 34wk
- induction of labor or c/s depending on fetal presentation
- weigh risk of prematurity with risk of infection/ sepsis by remaining in utero
34-36wk = grey zone (equal risks)
36wk = risk of sepsis > risk of prematurity
Define preterm labor
PTL = regular contractions causing a cervical change occurring between 20-37wk GA - very preterm = <32wk - extreme preterm = <28wk leading cause of infant mortality approx. 10% pregnancies
Symptoms PTL
- regular uterine contractions
- pelvic pressure, vaginal bleeding
- change in vaginal discharge
- low back pain
- cramping
Causes of PTL
- premature activation of maternal or fetal HPA axis (increased CRH -> increased cortisol; increased fetal DHEAS -> increased placental E)
- inflammation/ infection (chorioamnionitis, decidual) (increased cytokines -> increased PG -> increased contraction; breakdown membranes and cervix)
- decidual hemorrhage
- pathologic uterine distension
Do you do sterile speculum exam or cervical exam in PTL?
Sterile speculum exam if suspicion of PROM
Cervical exam if PROM and placental prevue ruled out - for dilation, effacement and consistency
Investigations PTL
- urine C&S
- vaginal swab for FFN between 24-34wk GA (high negative predictive value)
- vaginal swab for BV
- vagina/rectal swab GBS
- cervical swab for gonorrhoea, chlamydia
- US for cervical length, fetal presentation, amniotic fluid level, fetal growth
Diagnosis PTL
regular uterine contractions leading to cervical dilation (>2cm) and/or effacement (>80%)
How do you suppress labor in stable PTL?
Tocolysis
- suppress labor <48h
- CCB (nifedipine = first line)
- PG synthesis inhibitor (Indomethacin - limit use to <32wk GA)
+ steroid benefit
criteria - PTL, live immature fetus (no ROM, cervix <4cm), no CI
Enhance fetal lung maturity?
<34wk GA
- betamethasone (celexone) 12mg IM q24h x2
- dexamethasone 6mg IM q12h x4
Management PTL <34wk
- tocolysis and steroid
- enhance fetal lung maturity
- cervical cerclage if very preterm - pt education and cervical surveillance (repeat TVUS, FFN)
Management PTL >34wk
- IV hydration
- bed rest LLDP
- pain control
- US - BPP, estimated GA, presentation, EFW, placental location
- prophylactic abx (PPROM, GBS +)
- avoid repeated pelvic exam to reduce risk of infection
- patient education
CI tocolysis
Maternal
- bleeding, HTN, DM, eclampsia, preeclampsia, cardiac/ renal/ pulmonary disease, chrioaminionitis
Fetal
- anencephaly, fetal distress, IUFD, IUGR, erythroblastosis fetalis
Common aetiologies APH?
- abruption
- placenta previa
- vasa previa
- cervical pathology
Abruption
separation placenta from uterus before delivery of fetus (>20wk GA)
RF = age, smoking, cocaine, HTN, thrombophilia, trauma, hx abruption
- multiple gestations
- PPROM, chorioamnionitis, polyhydramnios
Dx - bleeding, abdo pain, regular contractions, uterine hypertonus, fetal distress
Inv - CBC, liver and renal function, coagulation studies (fibrinogen included), type and crossmatch
Management - maternal stabilization; Rh immunoglobulin (if mom RH-); deliver if fetal distress of term infant; expectant management if mother and premature infant stable (steroids if <34wk, no tocolysis, consider transfer)
Placenta previa
- placenta covers or is close (<2cm) to cervical os
RF - previous prevue, age >35y, parity >3, previous c/s or uterine surgery, smoking
- multiple gestation
Dx - bleeding, painless, digital cervical exam CI due to high risk of severe hemorrhage
Inv - US (confirm), CBC, type and crossmatch
Tx - maternal stabilization
- Rhogam if Rh-
- expectant management if 24-36wk GA and stable
- c/s 36-37wk GA
Vasa previa
Velamentous insertion of umbilical cord vessels into placenta, so vessels traverse cervical os before entering placenta
- high fetal mortality rate if active bleeding
RF - multiple gestation
- prevue, bilobed placenta, velamentous cord insertion, IVF pregnancy
Dx - bleeding painless
Inv - cbc, type and cross match
- speculum exam and Apt test
- US color Doppler if vasa prevue suspected (before bleed)
Tx - steroids 28-30 wk GA
- manage inpt from >30-32wk
- elective delivery at 34-36wk GA
- emergent delivery if bleeding (50% fetal mortality)
Cervical pathology re: APH
- cervical polyp, ectropion, cervical dilation, infection
RF - previous cervical polyp, RF STD, recent internal exam, intercourse
Dx - bleeding, painless or associated with cramping
Inv - speculum exam, pap smear, swab G&C
+/- US for cervical length if cervix appears short or associated with cramping/contractions
Tx - depending on etiology
- tx cervicitis
- DON’T remove cervical polyp - refer to colposcopy if AbN appearing/ AbN pap smear
Prevention of RhD isoimmuization/causes/ consequences?
RhD isoimmunization leads to:
- fetal/neonatal hemolytic anemia +/- hyperbilirubinemia
- hydrops fetalis
Amount of RhD + blood required to cause isoimmunization is small (<0.1mL)
Causes of isoimmunization
- fetomaternal hemorrhage at delivery, prev. ectopic pregnancy or abortion
- spontaneous antenatal fetomaternal hemorrhage
- invasive procedures during pregnancy (cerclage, amniocentesis)
Prophylaxis for all Rh- women
- one prophylactic dose (300 micrograms) of RhoGAM (reduced rate of developing antibodies to Rh Ag)
- at 28wk unless father of baby known Rh-
- within 72h of delivery of Rh+ baby
- following T1 miscarriage, threatening miscarriage, induced abortion, ectopic pregnancy, or molar pregnancy
- postinvasive procedures (CVS, amniocentesis, fetal blood sampling)
- any t2/t3 bleeding, external cephalic version, blunt abdo trauma
Define intrapartum care
- care of mother and fetus during labor
Define labor
- process by which products of conception are delivered from uterus by progressive cervical effacement and dilatation in the presence of regular uterine contractions
Define Braxton Hicks contractions
- irregular contractions, not associated with any cervical changes or descent of fetus
What percentage of labor (spontaneous) is between 37-42 wk GA?
85%
Is the uterus densely innervated?
NO
What does myometrial activity of the uterus depend on?
- Fetal and maternal paracrine/autocrine factors
- Intrinsic factors within myometrial cells
4 phases of myometrial activity in pregnancy?
0 = myometrial inhibition
- during pregnancy the uterus remains quiescent because inhibitors active
- putative inhibitors = progesterone, prostacyclin, relaxin, NO, placental CRH
1 = myometrial activation
- as term approaches
- uterus activated in response to uterotropins (i.e. E)
- result: (a) uterus becomes primed, (b) have development of regular, rhythmic contractions
2= stimulatory
- stimulation of primed uterus by uterotonic agonists (oxytocin, PGE2, PGF2alpha)
3= Involution
- occurs after delivery
- mediated by oxytocin
Fetal factors promoting labor?
- activation of fetal HPA axis -> increased cortisol which acts on placenta -> increased E production -> increased E:progesterone ratio
- result = increased PGF alpha release; increased myometrial response to oxytocin; increased contractions
Maternal factors promoting labor?
- activation of maternal HPA axis -> possible activation of fetal HPA
- oxytocin -> increase PG receptors, increase oxytocin receptors, increase gap junctions in uterus
Myometrial factors promoting labor?
- increased free intracellular Ca++ -> contraction of uterine myocyte cells
- possible mechanotransduction through stretching or shortening
How many stages of labor?
4
First stage of labor
Interval between onset of labor to full cervical dilation (10cm) - nulliparous 10h; multiparous 8h
2 phases
a) Latent phase - begins with onset of regular uterine contractions with slow cervical dilation up to 3-4cm
- Nulliparous 6.5h (prolonged >20h)
- Multiparous 4.5h (prolonged >14h)
b) Active phase - increased rate of cervical dilation to maximum, regular contractions, descent of fetus
- Nulliparous cervical dilation 1.2cm/h; fetal descent >1cm/h
- Multiparous cervical dilation 1.5cm/h; fetal descent >2cm/h
Second stage of labor
interval between full cervical dilation and delivery of infant
- nulliparous 50min (prolonged, no epidural >2h)
- multiparous 20min (prolonged, no epidural >1h)
Third stage of labor
interval between delivery of infant and delivery of placenta
- 10min (prolonged if >30min)
Fourth stage of labor
Interval from delivery of placenta through to resolution of physiologic changes of pregnancy
- 6wk
Define cardinal movements of labor
Sequence of movements that involve change position of fetal head that enables the fetus to successfully negotiate the pelvis during labor
What are the cardinal movements of labor?
- Engagement - widest diameter of fetal head (biparietal diameter) enters the maternal pelvis below the plane of the pelvic inlet
- Descent - downward passage of presenting part through the pelvic floor; greatest rate is during second stage of labor
- Passive flexion of fetal occiput permits smallest diameter of fetal head (suboccipitobregmatic, 9.5cm) to be presented for optimal passage through pelvis
- Internal rotation - rotation of occiput from its original position toward symphysis pubis (OA), which is ideal, or toward sacrum (OP); this enables AP diameter of fetal head to line up with the AP diameter of pelvic outlet
- Extension - delivery of fetal head by extension and rotation of occiput around symphysis
- Restitution and external rotation - with fetus’ head free of resistance, it untwists, causing the occiput and spine to line in same plane
- Expulsion - delivery of anterior shoulder under symphysis pubis followed by quick expulsion of rest of body
Do you do a sterile speculum exam or vaginal exam in suspected placenta previa?
Neither!! They’re contraindicated
Vaginal exam in management of labor
Sterile vaginal exam to determine cervical dilation and effacement as well as position and station of fetus
indications
- on admission (if no placenta previa)
- q2-4h in first stage and q1h in second stage
- at ROM to evaluate cord prolapse; if pt not contracting, perform sterile speculum exam only
- before intrapartum administration of analgesia
- when pt feels urge to push (determine if cervix fully dilated)
- evaluate cause of reduced FHR (r/o cord prolapse or uterine rupture)
What is dilation
estimated measure of diameter of internal cervical os
What is effacement
shortening and thinning of the cervix expressed as length (cm) or percentage (0% = no reduction vs. 100% = minimal palpable cervix)
What is position
Position of presenting part of fetus relative to maternal pelvis; most commonly OA but can be OP or OT
What is station
Estimated distance (cm) of leading presenting part relative to ischial spines - at level of spines = 0 (engaged) vs. cm below (+1 to +5) and cm above (-1 to -5)
Normal vs. atypical vs. abnormal baseline tracing fetal HR
110-160bpm = normal
atypical = bradycardia 100-100 atypical = tachycardia >160 bpm for <30min, rising baseline
abnormal = bradycardia <100 abnormal = tachycardia >160bpm for >30min, erratic baseline
Normal vs. atypical vs. abnormal variability in fetal HR
normal - 6-25 bpm, <5bpm for <40min
atypical - <5bpm for 40-80 min
abnormal - >80min, >25bpm for >10 min, sinusoidal
Normal vs. atypical vs. abnormal decelerations fetal HR
normal = none or occasional uncomplicated variables or early decelerations
atypical = repetitive (>3) uncomplicated variable decelerations; occasional late decelerations; single prolonged deceleration
abnormal = repetitive (>3) complicated variables:
- deceleration to 70bpm for 60sec
- loss of variability in trough of baseline
- biphasic decelerations
- overshoots
- slow return to baseline
- baseline lower after deceleration
- baseline tachycardia or bradycardia
- repetitive (>=3) complicated variables:
single prolonged deceleration (>2min but <10min)
Normal vs. atypical vs. abnormal accelerations fetal HR
normal = spontaneous accelerations present (>2)
- increases 15bpm for 15s
- increases 10bpm for 10s if <32wk GA
- accelerations present with fetal scalp stimulation
atypical = absence of acceleration with fetal scalp stimulation
abnormal = usually absent
Normal vs. atypical vs. abnormal action fetal HR
normal = NST may be discontinued;
EFM may be interrupted for periods up to 30min, if maternal fetal condition stable and/or oxytocin infusion rate stable
atypical = NST continued monitoring required, arrange BPP;
EFM further vigilant assessment required, especially when combined features present
abnormal = NST continued monitoring required; consider BPP and prepare for possible delivery
EFM - action required; review overall clinical situation, obtain scalp pH if appropriate/ prepare for delivery
What does fetal cardiotocograpy (CTG) measure?
FHR
and simultaneous uterine contractions
Frequency of intermittent auscultation (IA) - if no RF for adverse perinatal outcomes
one full minute after contraction - q1h during latent phase, q15-30min in active phase, q5min in second stage
What does EFM stand for?
continuous electronic fetal heart monitoring
- for pregnancies at risk of adverse perinatal outcomes or non reassuring auscultation
- internal via fetal scalp electrode or external via Doppler
Types of decelerations in labor
Early
Variable
Late
Early labor deceleration
- head compression -> vagal slowing of heart
- 2nd phase labor
- uniform shape
- FHR: gradual decrease and return to baseline
- coincides with contraction
Variable decelerations
- cord compression
- variable shape, onset, duration
- FHR: abrupt drop and return to baseline
- most common deceleration
complicated: - deceleration to <70bpm
- > 60bpm below baseline
- lasts >60s
Late deceleration
uteroplacental deficiency due to maternal hypotension, uterine hyper stimulation, placental dysfunction
result = hypoxia +/- acidosis of fetus
- uniform shape
- gradual decrease
- late onset (end of contraction)
- can be associated with change in baseline or reduced variability
Causes of decreased of absent fetal HR variability
- persistent hypoxia leading to acidosis
- fetal sleep
- medications - narcotics, sedatives, b-blockers
- prematurity
- fetal tachycardia
- -> investigate if >40min
Manage atypical or abnormal FHR tracing
- recheck
- call backup
- LLDP maternal - relieves compression of IVC by gravid uterus
- provide fetus O2 by 100% O2 mask to mother
- stop augmentation of labor - reduce hyperstimulation
- fetal scalp stimulation
- r/o causes of uteroplacental deficiency (correct maternal hypotension - IVFs, ephedrine)
- amniotomy
- fetal scalp electrode if unable to obtain adequate tracing with external monitoring
- measure fetal scalp blood pH (pH >7.25 = normal; pH <7.2 = fetal acidosis)
- amnioinfusion - protects cord from compression
GBS Prophylaxis
Screen at 36wk (antenatal care) - all women unless documented GBS bacteruria in current pregnancy or previously affected infant with GBS
- minimum 4h of intrapartum rx before delivery (still give if delivery imminent–> bactericidal levels in cord blood after 30min)
Indications for prophylaxis
- positive GBS screen
- unknown GBS status and other Bfs for neonatal disease (prev. infant with invasive GBS infection, GA <37wk, >18h since ROM, and GBS bacturia in current pregnancy)
IV Abx
- Penicillin G 5million units IV then 2.5 million units q4h
- Cefazolin 2g IV then 1g q8h (non-anaphylactic pen allergy)
- Clindamycin 900 mg IV q8h (anaphylactic pen allergy)
- Vancomycin 1g IV q12h (anaphylactic pen allergy)
Medication for analgesia during labor
Entonox - mixture of nitrous oxide and O2 via mask (not passed to fetus)
Narcotics - morphine 5-10mg IM in early labor, 2.5mg IV active labor; or fentanyl 0.5mg/kg IV
- can cause respiratory depression in neonate, reverse with Narcan 0.01mg/kg
Regional anesthesia - loss of pain below T8/T10 with varying motor block
- hydrate patient with dextrose free isotonic IV fluid before epidural
Epidural CI and risks
CI
- pt refusal
- untreated coagulopathy
- infection to lumbar area
- refractory hypotension/ hypovolemia
- active neurologic disease
- septicemia
Risks
- infection
- maternal hypotension
- neurologic complication (spinal headache, back pain, nerve palsies)
- toxic drug reaction
- rare neurologic disease
Types of episiotomies, indications, complications
- medial (midline) - incision through central tendon of perineal body (easy repair, improved healing)
- mediolateral - incision through elevator and bulbocavernosus and superficial transverse perineal muscles (less likely to extend into anal sphincter and rectum)
indications
- delivery with high risk of perineal laceration,
- soft tissue dystocia
- immediate delivery of compromised fetus
- instrumental delivery (optional)
complications
- infection
- hematoma
- fistula formation - rectovaginal
- fecal incontinence
- medial - likely to extend into anal muscle/rectal muscosa
- mediolateral - increase scar tissue, blood loss, pain, difficult repair, dyspareunia sequelae
Type of operative deliveries
Vacuum extraction - suction/traction instrument used to deliver fetus
Forceps - classified according to level + position of fetal head in birth canal at time forceps applied (low/ outlet, mid, high)
C/S - low transverse incision
Shoulder dystocia definition
- life threatening emergency
- impaction of anterior shoulder behind pubic bone after delivery of head
- turtle sign = retraction of delivered fetal head against the bottom of symphysis pubis
RF and complications of shoulder dystocia
RF
- maternal: obesity, pelvic abnormality, GDM, postdate pregnancy, prev. shoulder dystocia
- fetal: macrosomnia
- labor: prolonged active phase of first stage, prolonged second stage, assisted vaginal delivery (forceps)
complications
- maternal: PPH, symphyseal separation or diathesis, third- or fourth-degree lacerations, uterine rupture
- fetal - hypoxia, permanent neurologic damage, brachial plexus injury, clavicular #, humeral #, death
Management shoulder dystocia
ALARMER
- ask for help
- lift/ hyper flex both legs (McRobert maneuver)
- anterior shoulder disimpaction (suprapubic pressure by assistant or Rubin maneuver by MD)
- rotation of posterior shoulder (Wood corkscrew maneuver)
- manual removal of posterior arm
- episiotomy
- roll onto all 4s
Induction of labor requirements
- cervical assessment to determine best mode of induction/ cervical ripening
- normal “reassuring” fetal CTG
- cephalic/ vertex presentation
- access to proper fetal monitoring
Induction of labor methods
Requiring cervical ripening
- foley catheter, double lumen catheter (mechanical)
- Postaglandin E2 (intravaginal or intracervical gel, control release gel), Prostaglandin E1
Favourable cervix
- artificial ROM (amniotomy) - stimulates PG synthesis and secretion
- Oxytocin (Pitocin) - minimum dose to achieve cervical dilation of 1cm/h in active phase
(rapid infusion oyxotocin can lead to hypoTN and is antidiuretic)
Active management of 3rd stage of labor
- reduce risk of uterine atony and reduce postpartum blood loss
- oxytocin is ideal uterotonic agent (short t1/2 - 2-3min; minimal s/e; used in all women)
- 10U oxytocin IM or 5U IV over 1-2min with delivery of anterior shoulder
+ controlled cord traction
Signs of placental separation
- contraction and rise of uterus
- cord lengthening
- gush of blood
Can you solely apply cord traction?
No - always apply counter traction (push) above the pubic bone with one hand when applying cord traction (pull)
Cervical ripening
- done to promote softening, effacement and dilation of cervix in preparation for induction
- increase sensitivity of uterus to oxytocin
- necessity determined by Bishop score
Bishop score
cervical assessment tool
- cervical dilation (cm)
- effacement (%)
- station of presenting part
- cervical consistency
- position of cervix
score >6 = favourable cervix - high success of vag delicery
score <=6 = cervical ripening recommended (increased risk of failed induction)
Define dystocia
Abnormally slow progress of labor or FTP
Causes of dystocia
- arrest of dilation (stops for >2h in active phase) due to inefficient uterine action -> augmentation
- arrest of descent (fails to progress for >1h during 2nd stage) due to CPD (esp with adequate uterine contractions) or inefficient uterine action
- protraction of dilation (slow rate cervical dilation)
- protraction of descent (slow rate fetal descent during 2nd stage) due to CPD
- prolonged latent phase (>20h in primigravida and >14h in multigravida) due to improper dx of early labor
Is oxytocin used for induction or augmentation or labor?
Both
Management dystocia in labor
- appropriate intervention if necessary
- analgesia
- rest, ambulation
- amniotomy
- oxytocin augementation
- fetal health assessment
3 causes of FTP
power - inefficient uterine action (hypotonic, uncoordinated, difficulty pushing by mother)
passenger - fetal position (OP), size, presence of anomalies (hydrocephalus)
passage - pelvic structure (CPD), maternal soft tissue factors (full bladder)
Define postpartum care
- mother and fetus care during 6wk period following birth
Common postpartum complications
PPH
Postpartum fever (>38 on >2 occasions at least 4h apart, after first 24h period)
Postpartum blues (>80% new mothers; often between postpartum days 3-10)
Postpartum depression (depression within 1yr childbirth)
PPH
PPH - excessive blood loss in postpartum period
- primary vs. secondary (within 24hr vs. >24h)
>500mL blood loss in vag delivery or >1000mL blood loss in c/s
OR
blood loss threatening womens hemodynamic stability OR
10% drop in Hot between admission and last period
etiologies
- tone - uterine atony
- tissue - uterus for retained placental tissue or clots
- trauma - lower genital tract for laceratoins
- thrombin - review hx coagulopathy (vWD, ASA use, DIC, ITP, etc)
inv - CBC, coagulation profile
rx - based on etiology + resuscitation
Ddx postpartum fever
- breast engorgement, mastitis (S. aureus)
- atelectasis, pneumonia
- wound infection - c/s or episiotomy site (polymicrobial)
- endomyometritis
- thrombophlebitis, DVT
- UTI/ pyelonephritis
