When you go into labor, your membranes--also known as your "bag of waters"--will weaken and break, allowing amniotic fluid to leak out of your body as your baby is born. That fluid has been keeping your baby well protected against infection and injury while in utero. If your water breaks before labor actively begins, it's called PROM, or premature rupture of membranes.
PROM is fairly common, occurring in one out of every 10 pregnancies. About 90 percent of women whose membranes rupture near their due dates will go into labor within 24 hours, and 50 percent of preterm women will go into labor within that time. No matter how far along you are, though, your risk of infection--and your baby's--increases as more time elapses between your water breaking and your baby being born.
What to do. If you suspect that your membranes have ruptured, call your health care provider immediately. She will most likely want to examine you to determine if the fluid leaking from your vaginal area is from the amniotic sac, a urine leak, or some other type of vaginal discharge. If your membranes have ruptured, the next event will be determined by your baby's maturity and whether your provider suspects an infection.
After 36 weeks: If you're past your 36th week of pregnancy, your provider will probably wait at least 6-12 hours to see if you go into labor. Some providers will wait longer if your baby is moving and you have no signs of infection. Your doctor may allow you to wait at home, or she may ask you to come into the hospital. If you're not in active labor, she may then induce labor with Pitocin (a synthetic oxytocin that stimulates contractions) to decrease the chance of an infection occurring in you or your baby.
Between 32-36 weeks: Your provider may test your amniotic fluid to see if your baby's lungs are mature enough for him to breathe on his own. If they are, your provider may induce labor. If not, she may try to prolong your pregnancy through bed rest. She will induce labor if you show any signs of infection, such as fever or uterine tenderness; she may also give you steroids to improve your baby's lung function. In most cases, babies born after the 32nd week of pregnancy have few long-term complications.
Before 32 weeks: Your provider will almost certainly try to prolong your pregnancy unless there is evidence of active labor, infection, or abruption. She will probably admit you to a hospital with special perinatal services if her own hospital doesn't provide those. You may be given antibiotics to ward off infection and prolong the time from membrane rupture to delivery and steroids to promote your baby's lung development.