preterm labor and birth

Question 1

A 25 yo G4 P0212 at 24 weeks gestational age presents with painful contractions occurring every 10 minutes x 2 hours. On exam, the internal os is dilated 3 cm.

Answer 1

You administer nifedipine to the patient. Three hours later, the patient states she feels better. Uterine monitoring demonstrates that the contractions are irregular and occur about every 15-30 minutes.
The patient is discharged home and delivers a healthy baby at 37 weeks.

Question 2

prematurity

Answer 2

-Delivery before term (at or before 36 weeks, 6 days)
-Affects >350,000 U.S. neonates -> 10% of births

Question 3

preterm labor

Answer 3

-Signs and symptoms:
-Regular uterine contractions
-Effacement (shortening) of cervix
-Dilation of 2 cm or more

-Not all patients with preterm labor deliver prematurely!
-Approximately 30% of cases resolve spontaneously
-50% of patients hospitalized for preterm labor deliver at term

Question 4

factors associated with preterm labor

Answer 4

-!!!!!!!MCC: prior h/o preterm labor
-Prelabor rupture of membranes (PROM)
-dont need to know the rest
-African American race
-Cervical insufficiency

-Infections
-UTI
-BV
-Intra-amniotic infection (s/p amniocentesis, others)

-Polyhydramnios
-Multiple gestation
-Leiomyomata uteri
-Uterine anomalies
-Placental abnormalities
-Maternal smoking

Question 5

Measurement of cervical length via ultrasound

Answer 5

-Obtained by evaluation of the cervical length taken via transvaginal ultrasound
-Normal cervical length=40 mm

-Shortened cervical length defined as <25-30 mm
-Positive predictive value: 55-70%
-Negative predictive value: 89-94%!!!

Question 6

Answer 6

Shortened cervical length (1.74 cm)

Question 7

Answer 7

normal cervical length (5.0cm)

Question 8

dx of preterm labor: Fetal fibronectin (fFN)

Answer 8

-Swab that detects protein that is present in vaginal secretions after about 22 weeks
-Clinical pearl: do NOT use lubricant during pelvic exam when fFN will be tested
-Positive predictive value: 13-36%
-Negative predictive value: 95-97%

Question 9

management of preterm labor: tocolytics

Answer 9

-Treat with tocolytics x 48 hours
-Do NOT use tocolytics:
-Before fetal viability (24 weeks)
-Pre-eclampsia with severe features
-Severe fetal anomalies or fetal demise
-PPROM
-Maternal contraindication

-Nifedipine
-Indomethacin
-NSAIDs
-Beta blockers
-Magnesium sulfate

Question 10

additional measures used to manage preterm labor: glucocorticoids

Answer 10

-Used for enhancement of fetal lung maturity
-Steroids administered to mother
-Betamethasone 12 mg IM Q24h x 2 doses, OR
-Dexamethasone 6 mg IM Q12h x 4 doses

Question 11

additional measures used to manage preterm labor: fetal neuroprotection

Answer 11

-Fetal neuroprotection prior to 32 weeks GA
-Reduces risk of cerebral palsy in neonate
-Magnesium sulfate 4 gm IV loading dose followed by 1-2 gm IV infusion/hr

Question 12

progesterone for prevention of preterm labor

Answer 12

-Progesterone may be given via:
-17-alpha-hydroxyprogesterone caproate injection (weekly)
-Vaginal progesterone gel or capsules (daily)

-Usually begun in late 2nd trimester and continued until 36-37 weeks EGA

Question 13

which of the following meds is most correctly identified as tocolytic

Answer 13

-nifedipine!!!!!!!!!
-labetalol
-ritodrine
-micronized progesterone