Electrical Inhibition of Human Preterm Contractions

The purpose of this study is to explore a new method to stop preterm uterine contractions using an electrical device. The device, an "electrical pacemaker for the uterus," has been approved by the Food and Drug Administration (FDA) for clinical research in pregnant women. The purpose of this study is to evaluate the feasibility and safety of the device. The investigators hypothesize that human preterm uterine contractions can be safely and objectively inhibited with a weak electrical current provided by an electrical inhibition (EI)/uterine pacemaker device, and that this effect relates to the timing and length of EI exposure.

The purpose of this study is to determine the effectiveness of a new method of preventing the human preterm uterine contractions of labor during electrical monitoring. The objective is to test a method for the inhibition of human preterm uterine contractions with an electrical pacemaker, electrical inhibition (EI). The study will investigate EI associated changes in preterm uterine contraction frequency as monitored by objective uterine tocodynamometry and adjunct electromyography (EMG) and electrohysterogram (EHG). The endpoint is the statistically significant EI induced decrease in the gold standard tocodynamometric monitored preterm uterine contraction frequency. The adjunct EMG and EHG monitoring provides valuable adjunct data about the electrical activity of the preterm uterine contractions and the effect of EI on this activity.

The investigators hypothesize that human preterm uterine contractions can be safely and objectively inhibited with a weak electrical current provided by an electrical inhibition (EI)/uterine pacemaker device. This effect can be assessed by the use of a non-invasive tocodynamometer. It has been previously been shown that the frequency of contractions during preterm labor can be lowered by EI applied by the use of an intravaginal catheter carrying electrodes similar to a cardiac pacemaker (Karsdon et al). The investigators hypothesize that this effect relates to the timing and length of EI exposure.

Eligibility Criteria:
Inclusion Criteria:

* Wong-Baker pain score ≤ 6
* Pregnancy Depression Scale score \< 16
* Informed consent form signed and dated by patient
* Be willing and able to comply with study requirements
* Be between 18-50 years of age
* Be between 23 to 36 5/7 weeks pregnant with a singleton gestation
* Cervical dilation of ≤ 6 cm
* A normal spontaneous vaginal delivery (NSVD) expected
* Suspected to have preterm labor, as defined by the American College of Obstetricians and Gynecologists and the American Academy of Pediatrics, as follows.78

  * Persistent uterine contractions (4 every 20 minutes, or 8 every 60 minutes)
  * And any one or more of the following:
  * Documented cervical change
  * 1 cm cervical dilatation and progressing

    -\> 80% cervical effacement
  * Be admitted to the maternity unit with the diagnosis of preterm labor or preterm contractions

Exclusion Criteria:

* Severe preeclampsia
* Severe abruption placenta
* Abnormal placentation (i.e. placenta previa)
* Rupture of amniotic membranes
* Active preterm labor with cervical dilation \> 6 cm
* Exposed amniotic membranes
* Vaginal bleeding \> 10 cc
* Frank chorioamnionitis
* Fetal death
* Fetal anomaly incompatible with life
* Severe fetal growth restriction (EFW \< 5%)
* Uterine anomalies (i.e. bicornuate uterus, uterine didelphys)
* Mature fetal lung studies
* Maternal cardiac arrhythmias
* HIV, Hepatitis C, Hepatitis B
* History of herpes simplex virus (HSV)
* A permanent cardiac pacemaker
* A fetal cardiac arrhythmia
* Contraindication for tocolysis e.g. premature rupture of the amniotic membranes allowing for ascending intrauterine infection with group B streptococcus or GBS (beta hemolytic streptococcus, S. agalactiae) or other micro-organisms.
* IV or po narcotic pain medication \< 12 hours prior to admission (regional anesthesia, long acting oral maintenance opiates i.e. methadone, Suboxone, Subutex not included in exclusion criteria)