Clin: Obstetric Complications - Wootton Flashcards
birth that occurs after 20 weeks, but before 36.6 weeks gestation
preterm birth
uterine contractions accompanied with cervical change or cervical dilation 2cm and/or 80% effaced
labor
- preterm if 20-36 weeks
what is the leading cause of infant mortality?
preterm labor
what are the risk factors for PTL?
- african american
- decreased access to prenatal care
- high stress levels, poor nutrition
- previous hx of PTL
- bleeding in first trimester (inflammatory response)
- UTI/genital tract infections
- polyhydramnios (AFI greater than 20)
what are the four main causes of PTL?
- infection
- placental-vascular
- psychosocial stress and work strain
- uterine stretch (polyhydramnios, multiple babies)
what infections are associated with preterm delivery? (4)
- bacterial vaginosis
- GBS
- gonorrhea/chlamydia (link b/w infection and progressive changes in cervical length)
when is it important to use US for routine screening of cervical length?
with hx of PTL or cervical procedure (LEEP or CKC)
what is another screening tool for cervical length?
fetal fibronectin (FFN)
- released from basement membrane of fetal membranes
- released in response to disruption of membranes as with uterine activity, cervical shortening, or infection
- negative predictive value is GOOD, positive predictive value is LOW
alteration of what 3 factors may result in poor fetal growth?
- risk factors for PTL as well as growth restriction and preeclampsia
- immunologic
- vascular
- low resistance connection of spiral arteries
cortisol stimulates early placental corticotrophin-releasing hormone (CRH) gene expression and increased CRH levels are known to do what?
assist in labor at term
what hormone class affects blood flow and causes uterine contractions?
catecholamines
what are the two main risk factors for uterine stretch?
- polyhydramnios
- multiple gestations
what two factors must be present in order to dx PTL?
- uterine contractions
2. cervical change, cervical dilation of 2cm or greater and/or 80% effacement
what are the sx of PTL?
menstrual like cramping, low/dull backache, pelvic pressure, increase in discharge/bloody discharge and uterine contractions
hydration and bedrest can help resolve what in 20% of patients?
contractions
what is the management of PTL?
- GBS culture (give penicillin if needed)
- CBC, UA, urine culture
- US (for fetal presentation, growth, amniotic fluid volume, rule out congenital anomalies)
what meds can be given in PTL?
- MgSO4
- nifedipine
- prostaglandin synthetase inhibitors (indomethacin - only if < 32 weeks)
what is the drug of choice (arguably) in US?
MgSO4
- acts on cellular level, competes with calcium for entry into the cell
- may offer prevention against cerebral palsy
what are the side effects of MgSO4 on mom?
- warmth, flushing
- NV
- respiratory depression
- cardiac conduction defects and arrest at high serum levels
what are the side effects of MgSO4 on baby?
- loss of muscle tone
- drowsiness
- lower APGAR scores (worse on premature infants)
oral agent effective in suppressing preterm labor
- minimal maternal and fetal side effects (HA, flushing, hypotension, tachycardia)
- inhibits slow, inward current of calcium during the second phase of action potential
- may replace MgSO4 as drug of choice
nifedipine
inhibits prostaglandin production that induce myometrial contractions
- used on short term basis (mostly for extreme prematurity)
prostaglandin synthetase inhibitors
- indomethacin most commonly used (orally or rectally)
what are the side effects of indomethacin?
can result in oligohydramnois (decreases fetal renal function)
- can cause premature closure of fetal ductus arteriosus -> result in pulmonary HTN and heart failure
- infants exposed to indomethacin are at greater risk of necrotizing enterocolitis, intracranial hemorrhage
used to mature the fetal lung
- reduces motality and incidence of RDS and intraventricular hemorrhage
- given between 24 and 34 weeks
- either 2 doses of betamethasone, or 4 doses dexamethasone q 12 hrs
glucocorticoids
what is the rescue dose of corticosteroids?
single course of betamethasone is recommended for pregnant women between 34 and 37 weeks gestation, at risk of preterm birth within 7 days, and who have not received a previous course of antenatal corticosteroids
what is the recommended delivery method for preterm infants?
if vertex -> vaginal
if breech -> c-section (d/t increased risk of cord prolapse)
what is the most recent intervention to prevent PTL?
progesterone (IM) given 16-36 weeks
- vaginal progesterone used in women with shortened cervix
- arabin pessary (a little donut-shaped thing that keeps the cervix closed)
why should you not check the cervix of a presumed ruptured PRETERM patient?
it increases the risk of infection, especially with the prolonged latency before delivery
how do you confirm PPROM?
sterile speculum
- look for pooling (around cervix)
- nitrazine paper (turns blue)
- ferning on microscopy sample
what can cause a false positive on nitrazine paper?
- urine
- semen*
- cervical mucous
- blood
- vaginitis
what can cause a false negative on nitrazine paper?
- remote PROM with no remaining fluid
- minimal leakage
what does an intact amnoitic sac provide a barrier to?
infection!
- prevents chorioamnionitis (associated with 30% of preterm deliveries)
what are the maternal risks of PPROM?
- endomyometritis (infection of uterus postpartum)
- sepsis
- failed induction due to unfavorable cervix
what 4 factors influence management of PPROM?
- gestational age at time of rupture
- amniotic fluid index
- fetal status
- maternal status
what is the concern if ROM occurs before 24 weeks?
pulmonary hypoplasia and fetal structural abnormalities from position
what is the concern if amniotic fluid index is less than 5cm?
considered oligohydramnios -> lungs won’t develop properly
what is the expectant management of PPROM?
goal is to continue pregnancy until lung profile is mature
- most deliver at 34 weeks regardless of fetal lung maturity
- must monitor for signs/sx of chorioamnionitis
how is dx of chorioamnionitis made?
- maternal temp > 100.4
- fetal or maternal tachycardia
- tender uterus
- foul smelling amniotic fluid/purulent discharge
what is abx regimen for PPROM?
48 hr course IV ampicillin and erythromycin/azythromycin followed by 5 days of amox and erythromycin
- attempt to prolong latency
when does ACOOG recommend using steroids?
up to 34 weeks to reduce risk of RDS
when the birth weight of a newborn is below the 10% for a given gestational age
IUGR
birth weight at the lower extreme of a normal birth weight distribution
small for gestational age (SGA)
what are growth restricted fetuses at risk for?
- meconium aspiration
- hypoxia
- still birth
- polycythemia
- hypoglycemia
- cognitive delay
- poor nutritional intake/low maternal body weight
- cigarette smoking
- drug abuse
- alcoholism
- cyanotic heart dz
- pulmonary insufficiency
- antiphospholipid syndrome
- hereditary thrombophilias
- collagen vascular disease/autoimmune
maternal causes of IUGR
insufficuent substrate transfer through placenta as well as defective trophoblast invasion
placental causes of IUGR
what conditions can result in placental insufficiency?
- HTN
- renal dz
- placental or cord abnormalities (vilamentous cord)
- pre-existing diabetes
- inadequate or altered substrate
- intrauterine infections
- listeriosis
- TORCH (toxoplasmosis, rubella, CMV, herpes, syphillis)
- multiple gestations
fetal causes of IUGR
what should always be performed to diagnose IUGR?
- *doppler study**
- checks flow of blood to see if adequate amount is getting to baby
- also do US, PE for fundal height, amniocentesis, cord blood sampling
what is the primary screeing tool of IUGR?
fundal height measurement
what should you do if fundal height lags more than 3cm behind gestational age?
order US
what is measured on US to get fetal weight?
- biparietal diameter (BPD)
- head circumference
- abd circumference
- head-abd circumference
- femoral length
- amniotic fluid volume
- fetal weight
what is the management of IUGR?
- NST twice weekly
- biophysical profile
- doppler studies of umbilical artery
patient in lateral tilt position, FHR monitored with external transducer
- tracing observed for FHR accelerations that peak at least 15bpm above baseline and last 15 seconds
- may be necessary to continue tracing for 40 minutes or longer to take into account variations of fetal sleep-wake cycle
nonstress testing (NST)
if you suspect IUGR, and US confirms, >38-39 weeks?
> 38-39 weeks -> DELIVER
you suspect IUGR, and US confirms, but <38-39 weeks:
- if antenatal testing normal?
- if antenatal testing abnormal?
- if normal -> continue pregnancy
- if abnormal -> DELIVER
why do you need to monitor neonatal blood glucose and respiratory status after delivery of IUGR infant?
- blood glucose: neonates have less hepatic glycogen stores
- respiratory status: RDS more common
what are IUGR infants more at risk for developing?
adult onset diabetes, HTN, CAD
what is postmaturity syndrome?
related to aging and infarction of the placenta
- loss of subcutaneous fat, long fingernails, dry and peeling skin and abundant hair loss
if not affected by placental insufficiency, what are post-term pregnancies at risk for developing?
fetal macrosomia (>4500g)
- abnormal labor
- shoulder dystocia
what can cause post-term pregnancy?
- unsure dates
- fetal adrenal hypoplasia
- anencephalic fetuses (neural tube defect missing part of brain, skull and scalp)
- placental sulfatase def (x-link dz prevents conversion of sulfated estrogen precursors)
- extrauterine pregnancy
what is management of post-term pregnancy in the 41st week?
- begin antenatal testing to include twice weekly NST and BPP
- if testing abnormal or oligohydramnios -> INDUCE
induction in 41st week is preferred plan
what is management of post-term pregnancy in the 42nd week?
INDUCE
fetal death after 20 weeks gestation, but before the onset of labor
intrauterine fetal demise (IUFD)
- most cases unknown etiology (>50%)
- HTN/diabetes/SLE/thyroid
- cholestasis of pregnancy
- umbilical cord abnormalities
what is the management of IUFD?
- watch: up to 28 weeks gestation, spontaneous labor will occur within 2-3 weeks of fetal demise
- induce: most will require cervical ripening
- monitor coagulopathy: at risk of disseminated intravascular coagulopathy -> collect CBC, fibrinogen, PT/PTT
what should you search for after IUFD?
- TORCH titers
- parvovirus studies
- listeria cultures
- anticardiolipin Ab
- fetal xsome studies
- fetal autopsy
