Pregnancy and premature rupture of membranes

Definition
During pregnancy, a fluid-filled sac called the amniotic sac surrounds and cushions your baby in the womb. This sac typically breaks as part of the labor process. If your water breaks before labor begins, it's called premature rupture of the membranes.

Causes/associated factors
Various factors can increase your risk for premature rupture of the membranes, including:
genital tract infections (such as group B streptococcus, chlamydia, gonorrhea or bacterial vaginosis, which may be present without symptoms)
previous preterm or premature rupture of the membranes
prior preterm delivery (with or without premature rupture of the membranes)
increased pressure in the uterus due to excessive amniotic fluid (a condition known as polyhydramnios) or multiple pregnancy
vaginal bleeding during the first or second trimester (possibly due to conditions such as placental abruption, a complication caused by the accumulation of blood between the placenta and the wall of the uterus, or placenta previa, a condition in which the placenta blocks the birth canal)
cervical incompetence or abnormalities (such as a cervix shorter than 2.5 centimeters) or previous cervical surgery
two or more abortions
smoking during pregnancy

Signs/symptoms
A milky white vaginal discharge is normal during pregnancy. An increased amount of discharge or a watery discharge may indicate that your membranes have ruptured, however. If you feel a trickle of fluid or a larger gush or you notice wet underwear, notify your doctor immediately.
Amniotic fluid is normally colorless and may be odorless or slightly sweet smelling. If you have an infection, are bleeding, or your baby is in distress, the fluid may have a foul odor or be yellow, greenish brown or reddish brown. In some cases, it resembles pea soup or appears clear with green specks.


Diagnosis
Your doctor will do a pelvic exam to determine whether any fluid has collected in your vagina and to detect any changes (dilation or effacement) in the cervix. If fluid is actually flowing from the cervix, you'll be diagnosed with ruptured membranes.
If fluid isn't flowing from the cervix, you may need other tests, such as pH testing of the vaginal fluid with nitrazine paper. Vaginal secretions are normally acidic, but amniotic fluid is alkaline. If amniotic fluid is present, the paper will turn blue. This test is not foolproof, however, because other substances (including blood) can also turn the paper blue. Your doctor may also look at a drop of vaginal fluid under a microscope. When this fluid dries, a pattern that looks like a fern leaf will appear if amniotic fluid is present.

If the diagnosis is still uncertain, other tests may be done, including:

an ultrasound to measure the amniotic fluid volume (The ultrasound can also help your doctor determine your baby's gestational age.)
injection of dye through the abdominal wall into the amniotic fluid (If your membranes are ruptured, the dye will later leak out of the cervix into the vagina.)
further examination of the amniotic fluid to evaluate the baby's lung maturity and check for infection
lab tests of blood and vaginal fluid to check for infection

Treatment
Treatment depends on various factors, including your baby's gestational age, the cause of the rupture, your baby's position in the womb, and whether you or your baby are in danger of complications. Since research on premature rupture of the membranes is not definitive, treatment may vary among doctors.
If you're at or near term (at least 35 weeks gestation), your doctor may wait 12 to 24 hours to see if labor begins spontaneously. (About 90 percent of women who have premature rupture of the membranes begin labor on their own within 24 hours.) If you or your baby are at risk for infection or other complications, however, labor will be induced. In some cases, a C-section may be necessary.

If you have preterm premature rupture of membranes, especially at 34 weeks or earlier, your doctor may try to prolong your pregnancy to give your baby's lungs more time to mature. You'll be hospitalized and monitored for signs of infection. You may receive a corticosteroid medication to speed your baby's lung development and decrease the risk of lung disease. You may also receive antibiotics to treat or prevent infection, as well as medication to relax your uterus and stop contractions. Your baby will be monitored through ultrasounds, biophysical profiles and nonstress tests. When your baby is more mature, labor will be induced. In some cases, a C-section may be necessary. If complications such as infection or fetal distress are noted at any time after the membranes rupture, immediate delivery through induction or C-section may be necessary.

If possible, you may be sent home on bedrest, usually after several days in the hospital. You and your baby will be monitored closely at follow-up office visits, and home visits from a nurse may be arranged. You'll be instructed not to douche, have sex, or put anything in your vagina. It's best to shower instead of bathe in the tub. You'll be monitored for any signs of infection, such as fever, fast heartbeat, abdominal tenderness or foul-smelling vaginal odor. When your baby is more mature, you will return to the hospital for delivery.


Complications
The risk of complications from premature rupture of the membranes is greater the younger the baby's gestational age. Complications may include:
uterine infection
serious infection in the baby, such as pneumonia, bacteria in the blood or meningitis
lack of oxygen to the baby due to pressure on the umbilical cord (which normally floats in the amniotic fluid) or from prolapse of the cord through the vagina
abruptio placenta (early separation of the placenta from the uterus)
deformities of the baby's extremities and body
premature birth and associated complications

Prevention
The exact cause of premature rupture of the membranes is unknown, so prevention focuses on avoiding risk factors. For example:
Seek regular prenatal care.
Eat healthfully.
Drink an adequate amount of fluids.
Exercise regularly, unless your doctor directs you otherwise.
Wipe from front to back after urinating or having a bowel movement.
Washing the perineal area (the area between the vulva and the anus) daily.
Avoid multiple sexual partners.
If you smoke, quit.
Report any symptoms of vaginal infection (such as unusual discharge or odor) to your doctor.
Women who have a lower socioeconomic status may be at higher risk for premature rupture of the membranes. To help ensure a healthy pregnancy, learn about community resources such as financial support programs, food stamps, and the Women, Infants, and Children (WIC) Program. Consult your doctor or local county social service agency for details.