At 39 weeks, your baby is considered full term, and there are several evidence-backed ways to encourage labor to start or progress more quickly. Some are things you can try at home, others involve a conversation with your provider. What works depends largely on how ready your cervix already is, so understanding that context matters as much as knowing the techniques.
Why Cervical Readiness Matters
Before trying anything, it helps to know that your cervix has its own timeline. Providers assess cervical readiness using a scoring system that looks at five things: how dilated your cervix is, how thin it’s become (effacement), how soft it is, its position, and how far your baby’s head has descended into your pelvis. Each factor gets a point value, and the total ranges from 0 to 13. A score above 8 generally signals that your body is primed for labor. If your cervix hasn’t started these changes yet, most natural methods are less likely to tip things over the edge.
This is worth asking about at your next appointment. Knowing where you stand helps you set realistic expectations for whether home strategies might nudge things along or whether a medical approach would be more effective.
Natural Methods With Evidence Behind Them
Nipple Stimulation
Nipple stimulation is one of the most studied natural techniques. It triggers your body to release oxytocin, the same hormone that drives contractions. A Cochrane review pooling data from multiple trials found that 37% of women who used breast stimulation were in labor within 72 hours, compared to only 6% of women who did nothing. That’s a meaningful difference. The effect held up for both first-time and experienced mothers, though it didn’t reach significance for women whose cervix was still unfavorable. Most protocols in the research involved stimulating one breast at a time for about an hour, several times a day.
Sexual Intercourse
Semen contains the highest natural concentration of prostaglandins, hormone-like substances that soften and ripen the cervix. Orgasm also triggers oxytocin release, and the physical contact may stimulate the lower uterine segment. The theory is solid, and it’s been a longstanding recommendation from midwives. That said, the clinical evidence is thin. Only one small trial of 28 women has been conducted, and no meaningful conclusions could be drawn from it. It’s safe for most pregnancies (unless your water has broken or your provider has advised against it), and it certainly won’t hurt your chances.
Walking and Staying Upright
Gravity is a simple but real ally. Women who labor in upright positions, whether walking, standing, sitting on a birth ball, or kneeling, consistently have shorter labors than those lying on their backs. One study found that upright women spent about 1 hour and 22 minutes less in labor overall. In the first stage specifically, only 0.7% of women in upright positions labored more than 7 hours, compared to nearly 25% of women lying down. The pushing stage was also shorter by about 4 minutes on average. Upright positions help your baby’s head press more evenly on the cervix, which encourages dilation.
What Your Provider Can Do in the Office
Membrane Sweeping
A membrane sweep (also called stripping) is a quick procedure your provider can do during a regular cervical check. They insert a finger through the cervix and separate the amniotic membranes from the lower uterine wall. This releases natural prostaglandins and can kickstart contractions. In one randomized trial, 81% of women who had a sweep delivered within one to seven days, compared to 29% in the control group. Over 91% of the sweep group went into spontaneous labor without needing further induction.
It’s not the most comfortable experience. You can expect some cramping and possibly light spotting afterward, which about 10% of women reported. Braxton Hicks contractions may pick up. There’s a small chance your water could break, though rates of premature rupture were similar between the sweep and no-sweep groups in research. Most providers will offer a sweep starting around 39 weeks if your cervix is at least partially dilated.
Elective Induction at 39 Weeks
If you’re a first-time mother with an uncomplicated singleton pregnancy, elective induction at 39 weeks is now a well-supported option. The landmark ARRIVE trial, published in the New England Journal of Medicine, enrolled over 6,000 low-risk first-time mothers and found that those induced at 39 weeks had a cesarean rate of 18.6%, compared to 22.2% among those who waited for labor to start on its own. That translates to about 1 fewer cesarean for every 28 women induced. The induced group also had lower rates of high blood pressure complications during pregnancy.
Neonatal outcomes were similar or slightly better in the induction group. ACOG now supports discussing 39-week induction with healthy first-time mothers, provided the hospital has the staff and resources available. This is a conversation worth having with your provider if you’re interested, especially if you’re anxious about going past your due date or have risk factors for preeclampsia.
What Happens During a Medical Induction
If your cervix isn’t yet favorable, induction typically starts with cervical ripening. This might involve a small insert or oral medication that contains prostaglandins, or a mechanical method like a small balloon catheter placed in the cervix to encourage dilation. This phase can take several hours or even overnight.
Once your cervix is ready, you’ll receive synthetic oxytocin through an IV to stimulate regular contractions. The dose starts very low and is increased gradually every 30 to 60 minutes until contractions settle into a steady pattern. At levels mimicking what your body produces in natural labor, most women establish a good contraction rhythm. Your provider may also break your water (amniotomy) once you’re a few centimeters dilated, which typically shortens active labor by 1 to 2 hours.
The total timeline for an induction varies widely. If your cervix needs ripening first, expect the process to take 12 to 24 hours or sometimes longer. If your cervix is already favorable, active labor can begin within a few hours of starting the IV.
What to Skip or Approach With Caution
Castor Oil
Castor oil has a long folk history as a labor starter, and it does appear to stimulate uterine contractions, likely by irritating the intestines (which sit near the uterus). A meta-analysis found no serious harmful effects to mothers or babies, and outcomes like cesarean rates and newborn health scores were similar to control groups. The catch is the side effects: one study reported nausea in 48% of the castor oil group versus 0% in the control group, and diarrhea is nearly universal. When you’re about to go through labor, spending hours with cramping and diarrhea beforehand is a real drawback. It can also leave you dehydrated and exhausted before contractions even begin.
Herbal Supplements
Evening primrose oil, raspberry leaf tea, and various herbal tinctures are widely discussed online but lack reliable clinical evidence for inducing labor. Dosing is unstandardized, and some herbal products can interact with medications or cause unpredictable uterine activity. These aren’t necessarily dangerous, but they’re not proven to work either.
Putting It All Together
The most practical approach at 39 weeks combines several strategies. Stay active and upright as much as comfortable. Try nipple stimulation for sustained periods if you’re motivated to commit to it. Have sex if you feel up to it. Ask your provider about a membrane sweep at your next visit. And if you’re a first-time mother with no complications, have an honest conversation about whether a scheduled induction at 39 weeks makes sense for your situation. The evidence supports it as a safe choice that may actually lower your odds of a cesarean, which surprises many people who assume induction leads to more interventions.
Your cervix’s starting point is the single biggest predictor of how quickly any of these strategies will work. A cervix that’s already softening, thinning, and beginning to open is far more responsive to both natural and medical methods than one that hasn’t started changing. If your body isn’t quite there yet, patience and regular movement may be the most effective tools you have.