Uterine Electrical Activity Before and After Progesterone Treatment for Preterm Labor

In this study the investigators will compare the effects of vaginal progesterone,
intramuscular applied progesterone and topical progesterone on uterine electromyographic
activity (EMG)in patients in preterm labor. Electrodes will be placed on the abdominal
surface of pregnant patients in preterm labor and the EMG activity recorded for 30 minutes
before and following treatments for up to 48 hours. In addition data on delivery times will
be recorded when patients delivery vaginally or by Cesarian section. Eligibility criteria:
Healthy patients without infection or rupture of membranes with gestational ages between 24
to 34 weeks. Outcome measures: Comparisons of uterine EMG activity (EMG amplitude,
frequency, and specific information on EMG bursts) from measurements before treatment to
following treatments with progesterone preparations at various times (at 2,4,8, 12,24 and to
48 hours following treatment) and delivery times of patients on various treatments (hours or
days following treatments, average delivery times in patients treated by various
formulations). Comparisons of mean values in uterine EMG activity (EMG amplitude, burst
frequency and frequency of signals in a burst, power spectrum analysis of the bursts and
peak power density spectrum of bursts) from before treatment to following treatments at 2 to
24 hours will be compared. Also the time of delivery following treatments will be obtained
and the average time of delivery following the various treatments compared.

Inclusion Criteria:

- Healthy patients in preterm labor between 24 to 34 weeks of gestation presenting to
St. Joseph's Hospital and Medical Center.

- Preterm labor is defined as at least 6 contractions in 60 minutes with a cervix
either dilated to 2 centimeters or effaced to 80% and a cervical length measured by
ultrasound of less than 3 centimeters, and a positive fetal fibronectin.

- Maternal ages will be within 17 to 40 year-old range.

Exclusion Criteria:

- Patients with preterm premature rupture of membranes (PPROM) will be excluded from
the study, due to possibility of ascending infection, as will those patients with
suspected chorioamnionitis.

- Patients with medical conditions that contraindicate tocolysis, such as
non-reassuring fetal heart tracings, will also be excluded.