Preterm birth, its causes, prevention, complications and ramifications persist as an
important focus of obstetrical research. In the United States 11.8% of all live births occur
prior to 37 weeks gestation. As many as 45% of these deliveries will have been proceeded by
preterm labor with intact membranes.(2) Both preterm labor and preterm premature rupture of
membranes have both been associated with evidence intrauterine infection. While antibiotic
treatment in conservative management of preterm PROM remote from term has been shown to
significantly prolong pregnancy and reduce infant morbidity, (16) data regarding the
effectiveness of antibiotics for pregnancy prolongation in preterm labor are inconsistent.
(3-15) Currently, narrow spectrum antibiotics (penicillin or clindamycin) are given prior to
delivery to reduce the risk of neonatal Group B Beta Streptococcus (GBS) sepsis, however
broad spectrum antibiotic treatment of women with preterm labor for pregnancy prolongation
is not recommended.
Review of the literature regarding antibiotic treatment for pregnancy prolongation in
preterm labor reveals that most studies utilized single agent therapy, and no study has
evaluated the use of antibiotics for pregnancy prolongation in women with an advanced
cervical exam (>4cm). While a number of studies have shown significant pregnancy
prolongation in unselected populations,(5,12,13) only one study of 12 reviewed was able to
show a neonatal benefit to adjunctive antibiotic use.(12,20) Norman, et al was able to show
a reduction in the incidence of necrotising enterocolitis with the use of antibiotics. Given
the number of studies in this area, and the lack of supporting evidence, this likely
represents an alpha error. Another study by Svare et al was able to show a significant
decrease in NICU admissions for women treated with antibiotics in the setting of preterm
labor, however no change was reported in neonatal morbidities.
Our proposed study is designed to evaluate patients at particular risk for preterm delivery;
those with advanced cervical exam. In this randomized prospective controlled study, we
intend to examine the influence of adjunctive antibiotic use in preterm labor complicated by
a cervical exam of 4 cm or greater. We plan to compare a study group receiving
broad-spectrum antibiotics with a control group that will not receive antibiotics for
pregnancy prolongation. Both groups will receive antibiotics for GBS prophylaxis as
indicated. We hope to see a delay in delivery in the study group as a primary outcome.
Secondary outcomes will include the use of steroids, neonatal complications including
sepsis, intraventricular hemorrhage, periventricular leukomalacea, mechanical ventilation
and respiratory distress syndrome, retinopathy of prematurity and necrotizing enterocolitis,
and neonatal ICU stay.
1. All patients admitted with the diagnosis of preterm labor between 24 0/7 and 33 6/7
weeks gestation. Preterm labor will be defined by regular contractions and/or
cervical change from last documented exam.
2. Cervical exam 4 cm or greater
3. Intact membranes
1. Multiple gestation (>2)
2. Clinical evidence of chorioamnionitis, such as maternal fever, uterine tenderness,
3. Lethal fetal anomaly
4. Persistent vaginal bleeding, abruption, or placenta previa
5. Rupture of membranes
6. Maternal illness or fetal indication requiring delivery
7. Inability to give informed consent
8. Serious allergy to study medications. GI discomfort will not be considered a drug