RISK FACTORS
• Prior preterm delivery
• Multiple gestation
• Bacterial vaginosis
• Three or more fi rst-trimester abortions
• Previous second-trimester abortion
• Cervical incompetence
• Abdominal surgery during pregnancy
• Uterine or cervica
RISK FACTORS
• Prior preterm delivery
• Multiple gestation
• Bacterial vaginosis
• Three or more fi rst-trimester abortions
• Previous second-trimester abortion
• Cervical incompetence
• Abdominal surgery during pregnancy
• Uterine or cervical anomalies
• Placenta previa
• Premature placental separation (trauma or drug abuse
- especially cocaine)
• Fetal abnormalities
• Hydramnios
• Serious maternal infection
• Vaginal bleeding in pregnancy
• Prepregnancy weight less than 45 kg (100 lb), BMI < 20
• Single parent
• No prenatal care
• Lower socioeconomic status
• Substance abuse (e.g., cocaine, tobacco)
• IUGR
GENERAL MEASURES
• Treat underlying risk factors with appropriate measures (antibiotics for infections, hydration for dehydration)
• If delivery is inevitable, but not immediate, consider transport to a tertiary care center or hospital equipped
with a neonatal intensive care unit
• If mother is at 24-34 weeks’ gestation and has no evidence of infection, administer glucocorticoids to reduce
incidence of neonatal respiratory distress, intraventricular hemorrhage and necrotizing enterocolitis
SURGICAL MEASURES For malpresentation or fetal compromise, consider cesarean delivery if labor is progressing
ACTIVITY
• Pelvic rest (no douching or sexual intercourse)
• Bedrest. Discontinue work or other physical activities.
• Hospitalization may be necessary if on intravenous tocolysis or if bedrest is impossible at home
DIET Liquids only or npo, if delivery becomes imminent
PATIENT EDUCATION Call physician or proceed to hospital whenever contractions last over an hour, low back pain that comes and goes, change in vaginal discharge, "menstrual cramping", or intestinal
cramping. In the presence of risk factors, patient should be counseled early in pregnancy.
DRUG(S) OF CHOICE
. Hydrate with 500 mL D5NS or D5LR for fi rst half hour
. For tocolysis, protocols include:
. Terbutaline 0.25 mg subcutaneously every 30 minutes up to 3 doses until contractions stop. Then 0.25 SQ every 6 hours for 4 doses (optional). Consider oral terbutaline 2.5-5 mg every 4-6 hours. If contractions persist or pulse is greater than 120, change to another tocolytic.
. Magnesium sulfate solution of 40 g per 1000 mL of D5NS. Bolus 4-6 g over 20 min, then begin infusion at 2 g/hr, increasing by 0.5 g/hr every 15-30 min to a maximum of 4 g/hr; check refl exes and serum magnesium levels (therapeutic is 6-8 mg/dL [2.47-3.29 mmol/L]). Stop for signifi cant side effects. When tocolysis occurs, decrease dose by 0.5 g/hr each hour to a minimum of 2 g/hr and then consider switch to oral therapy after 12 -24 hours.
. Antibiotics for group B strep prophylaxis pending cultures
. Glucocorticoids to reduce incidence of neonatal respiratory distress, protocols include:
. Betamethasone 12 mg IM two doses 24h apart OR
. Dexamethasone 6 mg IM bid x 4 doses OR
. Betamethasone 12 mg IM single dose can be repeated after 7 days as long as preterm delivery is likely; discontinue at 34 weeks gestation
ALTERNATIVE DRUGS
• Nifedipine 10 mg po q 20 minutes x 3 doses, then 10 mg every hour. Check blood pressure often and avoid
hypotension. Concurrent use with magnesium sulfate is contraindicated.
• Indomethacin: 100 mg suppository per rectum q 12 hours x 2 doses, then 25 mg every 8 hours. Use no more than 72 hours due to risk of premature closure of ductus arteriosus, oligohydramnios, and necrotizing
enterocolitis.
PATIENT MONITORING
• Weekly offi ce visits and cervical checks or cervical ultrasound for those at high risk for preterm labor
• Ambulatory external tocodynamometry has not yet been proven efficacious for prevention of preterm labor
• Treating bacterial vaginosis in second trimester with metronidazole 250 mg tid for 7 days, erythromycin base
333 mg tid for 14 days; alternatively, using clindamycin 300 mg bid for 7 days may reduce risk of premature
delivery
• Controversy exists on whether maintenance tocolysis is useful, especially with negative fetal fibronectin testing
• The role of cervico-vaginal fetal fibronectin testing to assist risk assessment is controversial
• Fetal fi bronectin vaginal swabs if symptoms recur - to reassess risk of preterm birth
PREVENTION/AVOIDANCE
• Patient education at each visit in 2nd and 3rd trimester for those at risk; for general population, periodically
during the 2nd and 3rd trimester
• Consider cerclage placement before 22 week’s gestation for those at high risk because of an incompetent
cervix or progressive cervical shortening
POSSIBLE COMPLICATIONS Labor
resistant to tocolysis; pulmonary edema
EXPECTED COURSE/PROGNOSIS If membranes are ruptured and no infection, manage expectantly, but delivery often occurs within 3-7 days. If membranes are intact, treat until 36-37 weeks, gestational age.