EVIDENCE-BASED ANSWER
Yes, some do. Breast stimulation and electroacupuncture help, while other common remedies that have been studied are ineffective, possibly unsafe, or both. Unilateral breast stimulation shortens the time until the onset of labor in women at term (strength of recommendation [SOR]: A, systematic review). Electroacupuncture also may stimulate the onset of labor (SOR: C, observational studies).
Sexual intercourse doesn’t appear to ripen the cervix or stimulate labor (SOR: C, 1 observational study). Castor oil universally produces nausea and doesn’t promote labor (SOR: C, low-quality case-control study). Red raspberry leaf is likely safe but ineffective (SOR: B, 1 small randomized controlled trial); evening primrose oil is ineffective and possibly unsafe (SOR: B, 1 small retrospective cohort study); black cohosh and blue cohosh lack evidence of efficacy and may be unsafe (SOR: C, expert opinion and case reports).
Evidence summary
Breast stimulation works
A systematic review of 6 trials with a total of 719 participants compared unilateral breast stimulation with no intervention to induce labor in women at term.1 In 2 trials, the 300 participants stimulated 1 breast for 1 hour a day for 3 days; in the other 4 trials, 419 women stimulated either breast alternately for 3 hours a day.
Breast stimulation significantly reduced the number of women who hadn’t gone into labor at 72 hours compared with nonintervention (62.7% vs 93.6%; relative risk [RR]=0.67; 95% confidence interval [CI], 0.60-0.74; number needed to treat [NNT]=3.2). This result remained significant when primiparous and multiparous women were analyzed separately, but not in the 1 trial (37 participants) that reported on women with an unfavorable cervix.1 Breast stimulation also reduced postpartum hemorrhage (0.7% vs 6%; RR=0.16; 95% CI, 0.03-0.87; NNT=18.8).
None of the trials documented uterine hyperstimulation or meconium-stained fluid, and they didn’t find significant differences in the rates of cesarean section (9% vs 10%; RR=0.90; 95% CI, 0.38-2.12). One trial reported 4 perinatal deaths in a high-risk population—3 in the breast stimulation group and 1 in the control group—but this finding was not replicated in any other trials.1
Acupuncture may also help
A Cochrane systematic review evaluating acupuncture for inducing labor identified 1 randomized trial with methodologic flaws (allowing no conclusion), 3 case series, and 2 nonrandomized trials. The first case series used electroacupuncture at 38 to 42 weeks to successfully induce labor in 21 of 31 women. The second series, using acupuncture with and without electrical stimulation, induced labor in 10 of 12 women at 19 to 43 weeks. The third study induced labor with electroacupuncture in 78% of 41 women—34 term and postterm patients and 7 with a fetal demise.
In the first nonrandomized trial, 20 of 27 women at term who received electroacupuncture gave birth between 39 weeks 3 days and 40 weeks, compared with 47 of 102 women in the control group. In the second study, 31 of 35 women who received electroacupuncture reported increased intensity of contractions compared with none of the 35 women in the control group.2