Breaking water, also called amniorrhexis or rupture of membranes, is a normal part of labor and giving birth. The "water" is actually amniotic fluid, a straw-colored liquid with a faint odor that may be confused with urine. During pregnancy, this fluid surrounds and protects the fetus, cushioning it from pressure and concussion.
Spontaneous Rupture of Membranes
Ideally, your waters do not break until labor is well under way. In this case, it is the mechanical force of the contractions themselves that cause amniorrhexis. If you picture the amniotic sac as a water balloon, labor contractions squeeze the balloon until it breaks at a weak point -- usually at the bottom, near the cervix. If the head of the fetus is resting tightly against the mother's pelvis, it may act as a plug, preventing much of the amniotic fluid from escaping.
Premature Rupture of Membranes
In about 12 percent of pregnancies, the water breaks before the onset of labor -- an event called premature rupture of membranes or PROM. PROM is usually caused by an infection or by uneven pressure on the membrane from the body of the fetus. In cases where labor does not begin within 24 to 48 hours after the water breaks, a physician may choose to induce labor if the fetus is sufficiently developed to thrive outside the womb.
Preterm Premature Rupture of Membranes
Preterm premature rupture of membranes or PPROM is a subset of PROM that occurs before the 37th week of gestation. The immediate causes are the same as for late-term PROM -- infection or mechanical damage to the amniotic sac, leading to a tear that allows fluid to escape. Management of the condition depends on several health factors of both the mother and fetus, along with the amount of fluid lost, fetal age and level of development.
Risk Factors
Several risk factors predispose a pregnant woman to PROM and PPROM. These include previous cases of premature birth, pregnancy with twins, triplets or more, overproduction of amniotic fluid, incompetent cervix, an existing infection of the reproductive tract, bleeding during pregnancy, smoking and inadequate nutrition. Once a woman has had PROM or PPROM, she is more likely to have the same problem during future pregnancies.
