This is a pilot feasibility and acceptability study of a randomized clinical trial of pregnant women at 36 weeks of gestation and greater randomized to one of two arms at Yale New Haven Hospital: (1) Breast stimulation by hand or with an electronic breast pump (intervention) compared to (2) Exogenous oxytocin intravenous infusion (current standard of care, control). The pilot study will be randomized since one of the goals is to evaluate whether the idea of randomization would be acceptable to patients.

Almost four million women give birth each year in the United States with more than 27% of them undergoing induction of labor. Generally, labor induction is indicated when the benefits of expeditious delivery outweigh the risks of continuing the pregnancy. Additionally, labor induction is increasingly seen as a potentially therapeutic intervention even in the absence of any pregnancy complication for nulliparas after 39 weeks of gestation. However, induction of labor is usually associated with a longer latent phase compared to spontaneous labor, and may result in the need for cesarean delivery at an individual level when an induction attempt fails. Furthermore, it has been shown that women who are induced are less likely to be satisfied with their birth experience compared to those with spontaneous labor. Women are increasingly interested in a less medicalized birth experience and desire more control during their labor process. Lastly, the cost and infrastructure that would be required to universally apply routine induction of labor at 39 weeks of gestation are frequently cited as prohibitive, despite its associated improved outcomes.

Breast stimulation has been purported as a natural and inexpensive non-medical method for inducing labor that may give patients greater control over the process and have other potential clinical benefits. It is thought that breast stimulation induces uterine contractility by increasing the level of endogenous oxytocin hormone. Breast stimulation was historically used successfully for inducing contractions for the purposes of contraction stress testing.

A Cochrane review was performed in 2010 that compared breast stimulation with either no intervention or oxytocin infusion for labor induction. They found a significant reduction in the number of women not in labor at 72 hours (62.7% vs. 93.6%, RR 0.67, 95% CI 0.60-0.74) and the incidence of postpartum hemorrhage (0.7% vs. 6%, RR 0.16, 95% CI 0.03-0.87) among those who underwent breast stimulation compared to those who did not receive any intervention for induction. There were no benefits seen when comparing women who underwent breast stimulation versus those who received oxytocin alone. Despite the promising findings, the Cochrane Review raised the possibility of safety concerns due to one trial that reported four perinatal deaths (three in the breast stimulation group and one in the oxytocin group). However, that study was conducted in India, women were not monitored during breast stimulation, there was no clearly reported method of randomization, and there were very few study details divulged. The Cochrane Review ultimately had limited conclusions for several reasons. First, most included studies compared breast stimulation to no intervention, which is not the appropriate alternative when it has been determined that a labor induction is indicated. Additionally, most studies involved breast stimulation by hand at home for 1-3 hours per day and included only women with "low-risk" or un-specified risk pregnancies.

Only one previous trial has tested breast stimulation by breast pump, which showed that the time to reach the active phase of labor was significantly reduced among women who underwent breast stimulation compared to those who received oxytocin in the hospital setting. There was no difference in the length of labor between groups once women were considered to be in the active phase of labor or mode of delivery, but the trial included just 62 women. Reassuringly, only one of the 30 women assigned to breast stimulation requested discontinuation due to nipple soreness after 5.5 hours of intermittent stimulation.

Breast stimulation by hand or with an electronic breast pump is a biologically plausible method of labor induction that can potentially allow labor induction to be more efficient and may also have other benefits. These may include effects related to improved uterine contractility (e.g., successful labor induction and decreased postpartum hemorrhage risk), patient satisfaction with the induction process, and the stimulation of endogenous oxytocin which may improve postpartum breastfeeding and positive emotional responses. A well-designed randomized clinical trial is needed to evaluate the efficacy and safety of breast stimulation, particularly in comparison to the clinical alternative (use of exogenous oxytocin).

This is a proposed prospective parallel group randomized controlled external pilot study of breast stimulation by hand or with an electronic breast pump compared to exogenous oxytocin infusion to assess acceptability and feasibility prior to conducting a large non-inferiority randomized trial.

The two arms in this study are: (1) Breast stimulation by hand or with an electronic breast pump (intervention) compared to (2) Exogenous oxytocin intravenous infusion (current standard of care, control).

Inclusion Criteria:

1. Provision of signed and dated informed consent form
2. Stated willingness to comply with all study procedures and availability for the duration of the study
3. Age 18 years and older
4. Gestational age 36 weeks and greater at randomization
5. Vertex-presenting singleton gestation, or presenting gestation (a.k.a. Fetus A) is vertex-presenting in a multiple gestation
6. Undergoing induction of labor
7. Planned to undergo initiation of exogenous oxytocin infusion by their maternity care provider
8. Absence of tachysystole (defined as more than 5 contractions in 10 minutes averaged over 30 minutes), recurrent variable or late fetal decelerations, and bradycardia in the prior 30 minutes before randomization

Exclusion Criteria:

1. Unable to understand English
2. Planned for cesarean delivery or contraindication to labor by institutional policy (e.g., placenta previa, vasa previa, active genital herpes infection, uncontrolled HIV infection, previous transmural myomectomy)
3. Fetal demise
4. Major fetal anomaly suspected prenatally (defined as a fetal anomaly with anticipated neonatal intensive care unit admission)
5. Suspected fetal growth restriction (EFW <10th percentile)
6. Suspected alloimmunization
7. Unexplained active vaginal bleeding
8. History of mastectomy, breast lumpectomy, or contraindication to use of electronic breast pump
9. Known allergic reactions to components of the electronic breast pump or to synthetic oxytocin intravenous solution
10. Impairment of upper extremity motor function (e.g., quadriplegia)
11. Significantly impaired consciousness or executive function (e.g., intubated or sedated)