Premature rupture of membranes

Amniotic fluid is the water that surrounds your baby in the womb. Membranes or layers of tissue hold in this fluid. This membrane is called the amniotic sac.

Often, the membranes rupture (break) during labor. This is often called "when the water breaks."

Sometimes the membranes break before a woman goes into labor. When the water breaks early, it is called premature rupture of membranes (PROM). Most women will go into labor on their own within 24 hours.

If the water breaks before the 37th week of pregnancy, it is called preterm premature rupture of membranes (PPROM). The earlier your water breaks, the more serious it is for you and your baby.

In most cases, the cause of PROM is unknown. Some causes or risk factors may be:

• Infections of the uterus, cervix, or vagina
• Too much stretching of the amniotic sac (this may happen if there is too much fluid, or more than one baby putting pressure on the membranes)
• Smoking
• If you have had surgery or biopsies of the cervix
• If you were pregnant before and had a PROM or PPROM

Most women whose water breaks before labor do not have a risk factor.

The biggest sign to watch for is fluid leaking from the vagina. It may leak slowly, or it may gush out. Some of the fluid is lost when the membranes break. The membranes may continue to leak.

Sometimes when fluid leaks out slowly, women mistake it for urine. If you notice fluid leaking, use a pad to absorb some of it. Look at it and smell it. Amniotic fluid usually has no color and does not smell like urine (it has a much sweeter smell).

If you think your membranes have ruptured, contact your health care provider right away. You will need to be checked as soon as possible.

At the hospital, simple tests can confirm that your membranes have ruptured. Your provider will check your cervix to see if it has softened and is starting to dilate (open up).

If your provider finds that you have PROM, you will need to be in the hospital until your baby is born.

AFTER 37 WEEKS

If your pregnancy is past 37 weeks, your baby is ready to be born. You will need to go into labor soon. The longer it takes for labor to start, the greater your chance of getting an infection.

You can either wait for a short while until you go into labor on your own, or you can be induced (get medicine to start labor). Women who deliver within 24 hours after their water breaks are less likely to get an infection. So, if labor is not starting on its own, it can be safer to be induced.

BETWEEN 34 AND 37 WEEKS

If you are between 34 and 37 weeks when your water breaks, your provider will likely suggest that you be induced. It is safer for the baby to be born a few weeks early than it is for you to risk an infection.

BEFORE 34 WEEKS

If your water breaks before 34 weeks, it is more serious. If there are no signs of infection, your provider may try to hold off your labor by putting you on bed rest. Steroid medicines may be given to help the baby's lungs grow quickly. The baby will do better if its lungs have more time to grow before being born.

You will also receive antibiotics to help prevent infections. You and your baby will be watched very closely in the hospital. Your provider may do tests to check your baby's lungs. When the lungs have grown enough, your provider will induce labor.

If your water breaks early, your provider will tell you what will be the safest thing to do. There are some risks to giving birth early, but the hospital where you deliver will send your baby to the preterm unit (a special unit for babies born early). If there is not a preterm unit where you deliver, you and your baby will be moved to a hospital that has one.

PROM; PPROM; Pregnancy complications - premature rupture

Mercer BM, Gibson KS. Premature (prelabor) rupture of the membranes. In: Lockwood CJ, Copel JA, Dugoff L, et al, eds. Creasy and Resnik's Maternal-Fetal Medicine: Principles and Practice. 9th ed. Philadelphia, PA: Elsevier; 2023:chap 39.

Mercer BM, Chien EKS. Premature rupture of the membranes. In: Landon MB, Galan HL, Jauniaux ERM, et al, eds. Gabbe's Obstetrics: Normal and Problem Pregnancies. 8th ed. Philadelphia, PA: Elsevier; 2021:chap 37.

Updated by: John D. Jacobson, MD, Professor Emeritus, Department of Obstetrics and Gynecology, Loma Linda University School of Medicine, Loma Linda, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.