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Ronnie Falcao, LM MS, a homebirth midwife in Mountain View, CA

When is it Safe to Rupture Membranes?

Just so I'll be prepared when it's my time, in everyone's opinion, when is it acceptable to let the ob or midwife break your water? Is there a possibility of prolapsed cord if you don't? It will speed things up correct?

This is a complicated topic. Some things to consider:

If the membranes rupture "naturally", it is likely to be during a contraction, when there's the most pressure on the membranes. During a contraction, there's also the most force pushing the baby into the pelvis, and the baby has a better chance of getting there before the cord, if it is in any way likely to prolapse (long cord or high baby)..

When the membranes are artificially ruptured, the person doing it may opt to do it in between contractions, because most moms aren't thrilled about having somebody's hands in up to their cervix during a contraction, and the safest technique often involves putting two hands inside. When the membranes are ruptured in between contractions, the baby's head isn't being naturally pressed into the pelvis to keep the cord from prolapsing. However, it is possible for an assistant to hold the baby so that the head is deep enough into the pelvis that it would lessen the chance of prolapse. And, it is often possible to do a pinprick rupture of membranes by holding the membranes between your fingers and tearing them slightly or pricking them with a pin and then continuing to hold them like this while letting the fluid drain out slowly. If you do these last two together, you can greatly reduce the likelihood of any possible prolapse. And I've never seen it done in the hospital. (Probably too midwifey - have you ever noticed that hospital staff rarely touch the mom's belly - they don't seem to palpate for the baby's position to check for posterior or surprise breech, and they never seem to know where the baby's heart is likely to be - they just keep searching with the Doppler, which is apparently the ultimate authority.)

So, there's a little background on the prolapse issue.

There are midwives I know who would consider it a very grave intervention to rupture membranes and would only do it if:

1. The mom's been in active labor for several hours and the baby isn't descending, apparently because of lots of fluid.
2. You've been seeing funky heart tones that might suggest the baby's been releasing meconium, and the mom's at 8 cm and you want to be sure there's not thick meconium that would best be transported. (Legally anyway - it's not clear it's medically useful. The parents might want to make this choice.)
3. Birth is imminent. There's some fear that babies born in the caul might aspirate the fluid after they're born. This is similar to the fear that babies will breathe in water at a waterbirth, although I've never seen any studies to indicate that either fear was well founded.

Most caregivers are bright enough to prevent prolapse, and some are smart enough not to rupture membranes until active labor is well established.

However, there's not much you can do about the added stress on the baby. The biggest danger is that without all that fluid cushioning the cord, there may be cord compression that compromises the baby's oxygen supply. You know how antsy OBs get if you go postdates and they worry that you might not have "enough fluid"? Well, the concern about too little fluid before labor is because:

1. Too little fluid may reflect a degradation of the placenta.
2. Regardless of cause, too little fluid may increase the likelihood of cord compression.