Obstetrical Complications Flashcards
Preterm birth is defined as what?
Birth that occurs after 20 weeks but before 36 weeks and 6/7 days completed weeks of gestation
The diagnosis of preterm labor is defined as what events?
- Uterine contractions accompanied with cervical change
OR
- Cervical dilation of 2cm and/or 80% effaced
Which ethnicity is 2x more likely to experience pre-term labor?
African Americans 2x more likely than Caucasians
What 4 pathways are aimed at when preventing PTL?
- Infection (cervical)
- Placental-vascular
- Psychosocial stress and work strain
- Uterine stretch
What infections are associated with PTL?
bacterial vaginosis
group B strep
gonorrhea and chlamydia
There is a link between infection and progressive changes in cervical length and how is this related to preterm labor?
Risk of PTL ↑ as cervical length ↓
What are 2 screening tools that can be used to assess cervical length and to better predict risk of PTL?
- Ultrasound for routine screening of cervical length
- Fetal fibronectin (FFN) released from BM’s of fetal membranes in response to disruption of the membranes as w/ uterine activity, cervical shortening or infection
*negative predictive value is good; positive predictive value is low.
Alterations of any of the components of the placental-vascular pathway (immunologic component, vascular component, or low resistance connection of spiral arteries) is a risk factor for what?
results in poor fetal growth which is a risk factor for PTL as well as growth restriction and preeclampsia
Mental and physical stress are thought to induce a stress response that increases the release of what 2 things?
What is the effect of these 2 products?
Cortisol and catecholamines
Cortisol: released from the adrenal glands; stimulates early placental corticotrophin-releasing hormone (CRH) gene expression and increased CRH levels are known to assist in labor at term
Catecholamines: affect blood flow and can cause uterine contractions
The uterine stretch pathway in PTL is a risk factor in what women?
- polyhydramnios
- multiple gestations
What is the evaluation for PTL when a patient presents with any of the symptoms?
initial assessment done with cervical exam to assess dilation, effacement, and fetal presenting part
evaluate for any underlying correctable problems such as infection
external monitoring for uterine activity and fetal heart rate
reevaluate the cervix (usually at an hour) and during that hour oral or IV hydrate
cultures should be taken for GBS
also obtain an US
How is group B strep usually treated?
Antibiotics, typically penicillin, are given empirically to treat for GBS and usually discontinued if culture negative
Once you diagnose a patient with either 2 cm and/or 80% effacement or having made cervical change, what should you do next?
begin tocolysis (if gestational age is less than 34 weeks and there are no contraindications)
What are 3 tocolytic agents Whooten discussed?
Magnesium sulfate
Nifedipine
Prostaglandin Synthetase Inhibitors (indomethicin)
What is the MOA of magnesium sulfate?
it acts on the cellular level and competes with calcium for entry into the cell at the time of depolarization
What have some recent studies suggested about magnesium sulfate?
it may be more important in the role of neuroprotection
may offer prevention against cerebral palsy
What are the maternal side effects of magnesium sulfate?
feeling of warmth or flushing
nausea and vomiting
respiratory depression
cardiac conduction defects and arrest at high serum levels
What are the side effects in the neonate when mother is given magnesium sulfate?
loss of muscle tone
drowsiness
lower Apgar scores
What is Nifedipine
side effects
MOA
an oral agent effective in suppressing preterm labor
minimal maternal and fetal side effects
MOA: inhibits slow, inward current of calcium during the second phase of the action potential
What is the MOA of prostaglandin synthetase inhibitors?
What are the AEs of indomethacin?
they inhibit prostaglandin production that induce myometrial contractions
can cause oligohydramnios (decreases fetal renal function)
can cause premature closure of fetal ductus arteriosis and result in pulmonary hypertension and heart failure
infants exposed are at greater risk of necrotizing enterocolitis, intracranial hemorrhage
Which tocolytic used for PTL is only used on a short-term basis (mostly for extreme prematurity)?
Indomethacin
What are NSAIDs (Ibuprofen) used for in regards to PTL?
- Used to ↓ uterine activity
- NOT used for primary treatment of preterm labor
Glucocorticoids are given for fetal lung maturation between what weeks?
Between 24 weeks and 34 weeks gestation
A single course of betamethasone is recommended for pregnant women between which weeks of gestation if at risk of PTL within 7 days and who have no received a previous corse of antenatal corticosteroids?
Between 34 0/7 week and 36 6/7 weeks of gestation
What are some of the preventative measures being used for PTL?
- IM progesterone (Makena) given weekly from 16-36 weeks in women w/ prior hx of spontaneous PTL/PPROM
- Vaginal progesterone used in women w/ shortened cervix (<2.5 cm)
- Pessary (Arabin pessary) used in women w/ shortened cervix
Diagnosis of premature rupture of membranes (PROM) is based on what; confirmed how?
- History! —> loss of fluid + confirmation of amniotic fluid in vagina
- Rupture is confirmed using a sterile speculum (AmniSure Test)
What should you never do when assessing a presumed ruptured preterm patient?
Do NOT check the cervix —> ↑ risk of infection especially w/ prolonged latency before delivery
What are 3 tests that can be done to confirm PROM?
- Pooling
- Nitrazine paper (turns blue)
- Ferning
What could cause a false negative nitrazine result?
remote PROM with no remaining fluid
minimal leakage
What are the Maternal risks of PPROM?
endomyometritis (infection of uterus postpartum)
sepsis
failed induction due to infavorable cervix
Management of PPROM depends on what 4 factors?
- Gestational age at time of rupture: if <24 wks may lead to pulmonary hypoplasia
- Amniotic fluid index: any value <5cm is considered oligohydramnios
- Fetal status
- Maternal status
What is the goal of management for PPROM?
Continue the pregnancy until lung profile is mature
Regardless of fetal lung maturity, most women with PPROM will deliver at how many weeks gestation?
34 weeks
While managing woman with PPROM you must monitor for signs/sx’s of chorioamnionitis, which include what?
- Maternal temp >100.4 °F
- Fetal or maternal tachycardia
- Tender uterus
- Foul smelling amniotic fluid/purulent discharge
ACOG recommends using what drugs to attempt to prolong latency period of woman with PPROM?
- 48 hour course of IV Ampicillin and Erythromycin/Azithromycin
- Followed by 5 days of Amoxil and Erythromycin
What is the ACOG recommendation for use of steroids in patient with PPROM?
Use up to 34 weeks of gestation to ↓ risk of RDS
What is the definition of intrauterine growth restriction (IUGR)?
when the estimated fetal weight or abdominal circumference of a newborn is below 10% for a given gestational age
What is the definition of small for gestational age (SGA)?
birth weight at the lower extreme of normal birth weight distribution
What are the placental causes of IUGR?
insufficient substrate transfer through placenta as well as defective trophoblast invasion
What are some conditions which may result in placental insufficiency?
hypertension
renal disease
placental or cord abnormalities such as velamentous cord insertion
preexisting diabetes
What are the fetal causes of IUGR?
infectious disease such as intrauterine infections, listeriosis, or TORCH infections
congenital anomalies/genetic disorders
multiple gestations
chromosomal abnormalities
What is the primary screening tool used to assess/diagnose intrauterine growth restriction?
Serial fundal height measurements
If fundal height lags more than how many cm behind gestational age do you then order an ultrasound to assess intrauterine growth restriction?
Lags more than 3cm behind gestational age
How do you manage IUGR antepartum?
decrease any modifying factors: improve nutrition, stop smoking
goal: deliver before fetal compromise but after fetal lung maturity
Monitor: non-stress test twice weekly, biophysical profile, doppler studies of umbilical artery
if you suspect IUGR and you perform an ultrasound, how would you manage:
Normal ultrasound?
Ultrasound that shows IUGR between 3rd and 10th percentile with normal dopplers?
ultrasound shows IUGR less than 3rd percentile?
Ultrasound shows absent or reverse umbilical flow?
Normal: no intervention
ultrasound shows IUGR between 3rd and 10th percentile with normal dopplers: deliver between 38-39 weeks
ultrasound shows IUGR less than 3rd percentile: recommended to deliver at 37 weeks
earlier delivery is indicated in cases of absent or reverse umbilical flow
What is considered a normal doppler study of the umbilical artery?
What is considered to be a finding of a doppler study of the umbilical artery in a patient with IUGR?
normal: the umbilical flow velocity waveform of normally growing fetuses is characterized by high-velocity diastolic flow
IUGR: there is a diminution of umbilical artery diastolic flow
What 2 things should be monitored after birth of a fetus that was subjected to IUGR?
- Neonatal blood glucose because these neonates have less hepatic glycogen stores
- Monitor respiratory status as RDS is more common
babies born with IUGR are at greater risk for adult onset what?
diabetes, HTN, and CAD
What is the definition of a post-term pregnancy?
a pregnancy that continues past 42 weeks
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
if not affected by placental insufficiency, what are post-term pregnancies at risk for?
fetal macrosomia (greater than 4500 g)
abnormal labor
shoulder dystocia
c-section
what are some of the etiologies of post-term pregnancies?
unsure dates, fetal adrenal hypoplasia, anencephalic fetuses, placental sulfatase deficiency, and extra-uterine pregnancy
How should you manage post-term pregancies?
in the 41st week: begin antenatal testing to include twice weekly NST and biophysical profile; if abnormal or oligohydramnios then induce labor
in the 42nd week: induction of labor
what is intrauterine fetal demise (IUFD)?
fetal death after 20 weeks gestation but before the onset of labor
how do you manage IUFD?
watchful expectancy: only up till 28 weeks gestation, spontaneous labor will occur within 2-3 weeks of fetal demise
induction of labor: most will require cervical ripening with prostaglandin/laminaria/misoprostol/oxytocin
monitoring of coagulopathy: patients with IUFD are at risk of DIC; need to follow CBC, fibrinogen level, PT/PTT/INR
