As a pregnancy progresses, the amniotic sac fills with amniotic fluid that surrounds and cushions the baby. This sac is commonly referred to as the bag of waters. At some point before or during labor, the sac ruptures – also known as “breaking the water” – and the amniotic fluid leaks out through the vagina. This signals that labor is starting or progressing. But does breaking the water actually help speed up the labor process? Let’s take a closer look at what the research says.
What happens when the water breaks?
Rupturing of the amniotic sac, known medically as rupture of membranes (ROM), can occur at different times during pregnancy:
- Preterm premature ROM (PPROM) – rupture before 37 weeks gestation
- Term premature ROM – rupture between 37-42 weeks before labor starts
- Spontaneous ROM – rupture at the start or during labor
- Artificial ROM – rupture caused by medical intervention
Spontaneous ROM can happen any time during active labor. It may occur right at the start, during early labor when contractions are still light and far apart. Or it may not happen until transition stage, when labor is most intense right before the pushing stage.
According to ACOG, about 8-10% of pregnant women experience spontaneous ROM before the start of labor. For most women, the water breaks at some point once labor is underway.
When the amniotic sac ruptures, the forebag usually breaks first. This is the lower part of the membrane closest to the cervix. Women often feel a sudden gush or slow trickle of warm fluid from the vagina. The remaining fluid will continue to leak out gradually throughout labor.
Does breaking the water speed up labor?
Some doctors may recommend artificially rupturing the amniotic sac to try to move labor along. This amniotomy procedure is also called “breaking the water.” A hooked instrument is used to make a small tear in the amniotic sac, allowing amniotic fluid to drain out.
So does breaking the water actually accelerate labor and childbirth? Let’s examine what the research evidence tells us:
Cochrane review finds limited benefits
A 2018 Cochrane systematic review looked at 15 trials with over 5,000 women to assess labor effects of amniotomy. They found that artificially breaking the waters:
- Shortens the time from rupture until birth by about 1 hour 20 minutes on average
- Shortens first stage labor by about 1 hour 13 minutes
- May reduce rate of CS, but the evidence is uncertain
- Shows no other clear benefits or harms for mothers/babies
Overall, the review concluded that breaking the waters has “limited effects” on shortening labor duration and improving outcomes. Any benefits must be weighed against potential downsides like increased risk of cord prolapse after rupture.
Studies find mixed impact on labor duration
Other studies looking specifically at the effects of amniotomy on labor duration and progression have had mixed results:
- A 2018 study in 200 Indian women found that amniotomy shortened the time from 4-10cm cervical dilation by 2.4 hours compared to women with spontaneous ROM.
- A 2016 study in 120 Thai women found that amniotomy didn’t affect the length of the active phase of labor.
- A 2010 meta-analysis of 4 trials did not find a significant difference in length of first stage labor with amniotomy.
Overall, evidence indicates amniotomy may shorten labor by 1-2 hours, on average. But results vary between studies and individual women.
When are doctors more likely to break the water?
Doctors may decide to artificially rupture membranes during labor if:
- Labor stalls or is progressing very slowly
- Contractions are inadequate
- Need to attach internal monitors directly to baby’s scalp
- Mother has meconium-stained fluid and baby needs monitoring
It provides a way to potentially accelerate labor when needed. However, ACOG states that amniotomy should be used selectively, not routinely, due to limited benefits.
Risks and complications
Along with the potential to modestly shorten labor, breaking the water also comes with risks:
- Cord prolapse – Umbilical cord drops through the open cervix, cutting off baby’s circulation. Emergency C-section is needed.
- Infection – Bacteria may be introduced into the uterus, raising risk of maternal/newborn infection.
- Fetal distress – Changes in baby’s heart rate patterns may occur after rupture.
- Abruptio placenta – Rarely, the placenta may partially separate from the uterine wall.
The Cochrane review found no difference in rates of infection, fetal distress, or other adverse effects from amniotomy. But cord prolapse is a danger if membranes are ruptured when cervix is still undilated.
What if the water doesn’t break?
It’s common for labor to begin or progress significantly before membranes rupture. Contractions often become strong enough to dilate the cervix without the amniotic sac breaking first.
According to ACOG guidelines:
- Labor induction or augmentation can be performed if needed before rupturing the amniotic sac.
- As long as fetal monitoring is reassuring, it’s reasonable to continue labor for up to 24 hours without breaking the water.
- Amniotomy can be offered if labor stalls and maternal/fetal status is reassuring.
So while breaking the water may modestly shorten labor, it’s not always necessary for labor to continue progressing.
Are there methods to naturally rupture membranes?
Some natural methods claim to help trigger rupture of membranes at term:
Nipple stimulation
Stimulating nipples to release oxytocin may cause mild uterine contractions to put pressure on the amniotic sac. However, a 2018 Cochrane review found insufficient evidence that nipple stimulation effectively induces labor or ruptures membranes.
Acupuncture
A 2016 study found acupuncture performed on LI4 acupoints on the hand did not increase spontaneous ROM within 24-48 hours compared to sham acupuncture. More studies are needed.
Castor oil
Castor oil causes gastrointestinal cramping and diarrhea, which may stimulate uterine contractions. However, a 2018 review found castor oil ingestion often causes nausea/vomiting with no evidence it induces labor or ruptures membranes.
Herbal supplements
Some herbs like blue cohosh may stimulate uterine contractions, but can be dangerous and are not recommended for labor induction. There is no evidence they safely rupture membranes.
Physical techniques
Methods like stretching, squatting, abdominal massage lack evidence and are not recommended to rupture membranes. They could increase infection risk.
In summary, no natural methods are proven effective or recommended for rupturing membranes. Always consult your provider first before trying anything to induce labor.
What to do if your water breaks
If you think your water has broken, call your healthcare provider, advise them of any fluid leakage, and head to the hospital as recommended. Time any contractions. Go straight to L&D triage so nurses can confirm membrane rupture and check you and baby.
Don’t drink or eat anything until plans are made for either induction or expectant management (waiting for labor). Don’t try to induce labor yourself or do things that could introduce bacteria. Follow your doctor’s specific advice about when to come in and what to do after your water breaks.
Conclusion
While rupturing the amniotic sac may modestly shorten labor duration, current evidence indicates breaking the water has limited benefits for moms and babies overall. Artificially rupturing membranes does not reliably accelerate labor and should be used selectively based on specific clinical circumstances. Many women will begin labor and progress significantly before their water breaks. Natural methods aimed at triggering rupture lack sufficient evidence and are not recommended. If you experience signs of rupture of membranes, call your healthcare provider right away for evaluation and instructions.