Obstetric Complications

Question 1

Preterm birth is defined as a birth that occurs after 20 weeks but before 37 completed weeks of gestation. How is preterm labor (PTL) diagnosed?

Answer 1

Uterine contractions accompanied with cervical change or cervical dilation of 2 cm and/or 80% effaced

Question 2

Etiologies of preterm labor

Answer 2

Spontaneous
Multiple gestations
Preterm premature rupture of membranes
Pregnancy-associated HTN
Cervical incompetence or uterine anomalies
Antepartum hemorrhage
Intrauterine growth restriction (IUGR)

Question 3

Risk factors for PTL

Answer 3

SES factors: African American 2x more likely than Caucasian; Decreased access to prenatal care; High stress levels, poor nutrition

Medical/obstetric factors: previous hx of PTL, hx of 2nd trimester abortion, repeated 1st trimester abortions, bleeding in first trimester, UTI/genital tract infection, multiple gestation, uterine anomalies, polyhydramnios, incompetent cervix

Question 4

4 main pathways addressed in prevention of PTL

Answer 4

Infection (cervical)
Placental-vascular
Psychosocial stress/work strain
Uterine stretch

Question 5

How is PTL prevented via infection-cervical pathway?

Answer 5

Treat bacterial infections associated with preterm labor: Bacterial vaginosis, Group B strep, Gonorrhea, Chlamydia

[there is a link between infection and progressive changes in cervical length, and cervical length is a predictor for preterm birth risk]

Question 6

The relative risk of PTL increases as cervical length decreases. What are screening methods to determine cervical length?

Answer 6

Routine screening with US

Fetal fibronectin (FFN) — 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]

Question 7

How is the placental vascular pathway involved in risk for PTL?

Answer 7

Alteration of placental vasculature at the level of placental-decidual-myometrial interface may result in poor fetal growth, which is a risk factor for PTL as well as growth restriction and preeclampsia

Question 8

How is the stress-strain pathway involved in risk for PTL?

Answer 8

Mental and physical stress induce release of cortisol and catecholamines, which are associated with uterine contractions

Question 9

Symptoms of preterm labor

Answer 9

Menstrual like cramping, low/dull backache, pelvic pressure, increase in discharge/bloody discharge, and uterine contractions

Question 10

Management of PTL

Answer 10

Initial assessment with cervical exam to assess dilation, effacement, and fetal presenting part

Evaluate for underlying correctable problems such as infection (culture for group B strep)

External monitoring for uterine activity and fetal HR

Reevaluate cervix hourly and administer oral or IV hydration

CBC, urinalysis, and urine culture

Obtain US (fetal presentation, growth, amniotic fluid volume, r/o congenital anomalies)

Consider tocolytics

Question 11

Indications/criteria to begin tocolytics in PTL

Answer 11

2 cm dilation and/or 80% effaced, or made cervical change; and gestational age <34 weeks and no contraindications

Question 12

3 tocolytics used in PTL

Answer 12

Magnesium sulfate

Nifedipine

Prostaglandin Synthetase Inhibitors (Indomethacin)

Question 13

In the US, the tocolytic agent of choice in PTL is magnesium sulfate. Therapeutic serum levels range from 5.5 to 7.0 mg/dL. Typically a 6g loading dose is given IV, then 3g/hr for continuous maintenance. Therapy is continued until both doses of _____ are administered, and may be titrated down if uterine activity stops. Some studies have shown magnesium sulfate may play a role in _______ and possibly protects against cerebral palsy. It is currently indicated for use in less than 32 weeks gestation PTL.

Answer 13

Steroids

Neuroprotection

Question 14

Side effects of magnesium sulfate

Answer 14

Maternal: feeling of warmth and flushing, N/V, respiratory depression (with high serum levels), cardiac conduction defects and arrest (high serum levels)

Neonate: loss of muscle tone, drowsiness, lower apgar scores

Question 15

Oral agent effective in suppressing PTL with minimal maternal and fetal side effects including HA, cutaneous flushing, hypotension, and tachycardia

Answer 15

Nifedipine

Question 16

Tocolytic used on short term basis, mostly for extreme prematurity

Answer 16

Prostaglanin synthetase inhibitors

Question 17

Complications of prostaglandin synthetase inhibitor (indomethacin) when used as PTL tocolytic

Answer 17

Oligohydramnios

Premature closure of fetal ductus arteriosus —> pulmonary HTN and heart failure

Increased risk of necrotizing enterocolitis and intracranial hemorrhage

Question 18

When is ibuprofen indicated for tocolysis?

Answer 18

Not used for primary tx of preterm labor, but used to decrease uterine activity not associated with labor — to the point that hyperactive contractions are interfering with pt’s life

Question 19

Drug given to accelerate premature fetal lung maturation

Answer 19

Glucocorticoids (betamethasone, dexamethasone)

Given between 22-34 weeks gestation

Effects last 7 days

Question 20

A single course of ______ is recommended for pregnant women between 34-36 weeks of gestation at risk of preterm birth w/i 7 days, and who have not received a previous course of antenatal corticosteroids

Answer 20

Betamethasone

Question 21

Lower limit of preterm viability in weeks and grams

Answer 21

23-24 weeks or 500 grams

Question 22

PTL intervention used in women with previous hx of spontaneous PTL/PPROM, given weekly from 16-36 wks

Answer 22

IM progesterone (Makena)

Question 23

PTL intervention used in women with a shortened cervix (<2.5cm)

Answer 23

Vaginal progesterone (prometrium or crinone)

Pessary (arabin pessary)

Question 24

The etiology of PROM is unknown. What are some risk factors?

Answer 24

Vaginal/cervical infections
Abnormal membranes
Incompetent cervix
Nutritional deficiencies

Question 25

Why shouldn’t you check the cervix of a presumed ruptured preterm patient?

Answer 25

Increases the risk of infection, especially with prolonged latency before delivery

Question 26

3 tests used for confirmation of PROM

Answer 26

Pooling
Nitrazine paper
Ferning

[may also use US to evaluate amniotic fluid volume]

Note: false positives on nitrazine may be caused by urine, semen, cervical mucous, blood, or vaginitis; false negatives may occur with remote PROM with no remaining fluid or with minimal leakage

Question 27

In the management of preterm premature rupture of membranes (PPROM), the risk of preterm delivery must be balanced with the risk of infection, as an intact amnionic sac provides a barrier to ________, an infection of the membranes and fetal infection associated with about 30% of preterm deliveries

Answer 27

Chorioamnionitis

Question 28

Management of PPROM depends on gestational age at time of rupture, amniotic fluid index, fetal status, and maternal status. The goal is to continue the pregnancy until lung profile is mature. Most will deliver at ____ weeks regardless of fetal lung maturity (earlier with dx of chorioamnionitis)

Answer 28

34

Question 29

Signs/symptoms of chorioamnionitis

Answer 29

Maternal temp >100.4
Fetal or maternal tachycardia
Tender uterus
Foul smelling amniotic fluid/purulent discharge

Question 30

ACOG recommendations for abx and tocolytic usage in PPROM

Answer 30

For abx, ACOG recommends 48 hr course of ampicillin and erythromycin/azithromycin followed by 5 days of amoxil and erythromycin

For tocolytics, ACOG does not recommend for or against, they may be used if there is no evidence for chorioamnionitis and primary purpose is to have time to get steroid tx to baby

Question 31

Define intrauterine growth restriction (IUGR) vs. small for gestational age (SGA)

Answer 31

IUGR: birth weight of newborn is below 10% for given gestational age

SGA: birth weight at lower extreme of normal birth weight distribution

Question 32

Growth restricted fetuses are at risk for what complications?

Answer 32

Meconium aspiration
Asphyxia
Polycythemia
Hypoglycemia
Mental retardation
Adult onset of conditions such as HTN, diabetes, and atherosclerosis

Question 33

Maternal causes of IUGR

Answer 33

Poor nutritional intake/maternal low body weight

Cigarette smoking, drug abuse, alcoholism

Cyanotic heart disease

Pulmonary insufficiency (i.e., poorly controlled asthma)

Antiphospholipid syndrome

Hereditary thrombophilias

Collagen vascular dz

Question 34

Placental causes of IUGR involve insufficient substrate transfer through placenta as well as defective trophoblastic invasion. What conditions may result in placental insufficiency?

Answer 34

HTN (preexisting or gestational)

Renal disease

Placental or cord abnormalities such as velamentous cord insertion

Diabetes

Question 35

Fetal causes of IUGR

Answer 35

Intrauterine infections — listeriosis, TORCH

Congenital anomalies/genetic disorders

Multiple gestations

Chromosomal abnormalities

Question 36

How is IUGR diagnosed?

Answer 36

Primary screening test is PE of fundal height. If fundal height lags more than 3 cm behind the gestational age, then order an ultrasound

US is used routinely for high risk conditions that predispose to IUGR such as HTN, renal dz, diabetes, drug abuse, antiphospholipid syndrome, lupus

Question 37

Pre-pregnancy management of IUGR involves optimization of disease processes (i.e., blood sugar control, HTN control)

Antepartum management of IUGR involves decreasing any modifiable risk factors (improve nutrition, stop smoking, etc.) with the goal of delivering before fetal compromise but after fetal lung maturity. What tests are monitored in antepartum period?

Answer 37

Non-stress test 2x/week

Biophysical profile

Doppler studies of umbilical a. (Umbilical flow velocity waveform of normally growing fetuses is characterized by high-velocity diastolic flow, whereas with intrauterine growth restriction there is diminution of umbilical a. diastolic flow)

Question 38

T/F: Babies with IUGR require C-section delivery

Answer 38

False — IUGR is not an indication for C-section, but fetuses have less reserve and may have intolerance of labor

Require continuous fetal monitoring and other factors may necessitate C-section

Question 39

What tests should be monitored after birth of baby with IUGR?

Answer 39

Monitor neonatal blood glucose, as these babies have less hepatic glycogen stores

Monitor respiratory status as RDS is more common