Overview

When you are pregnant, a fluid-filled bag called the amniotic sac surrounds and protects the fetus. When a hole or tear forms in the sac, it's called a rupture of the membranes. Most women describe this by saying their "water broke."

Your membranes can break by themselves. This is called a spontaneous rupture of the membranes. It most often happens after active labour has started.

Sometimes the membranes may be ruptured by the doctor or midwife to start or speed up labour. This is called an artificial rupture of the membranes.

Your contractions may get stronger after your membranes rupture.

You may feel a large gush of fluid after the membranes rupture. The uterus keeps making amniotic fluid until the baby's birth. So you may still feel some leaking, especially right after a hard contraction (tightening of the muscles of the uterus).

Spontaneous rupture of the membranes

Sometimes it can be hard to tell if your membranes have ruptured. As you get closer to your due date, your uterus puts more pressure on your bladder. A strong Braxton Hicks contraction or sneeze can cause some urine to leak. You might mistake this for a rupture of the membranes.

If you are lying down when your membranes break, you are more likely to feel a gush of liquid. If the membranes break when you are standing up, you are more likely to feel just a trickle. That's because the baby's head gets pushed down against the cervix and acts like a cork when you stand.

If you think your membranes have ruptured:

• Call your doctor or midwife. He or she may want to check you as soon as your membranes rupture.
• Don't put anything in your vagina. Don't have sexual intercourse or flush the vagina with fluid (douche).

You can also go to the hospital or birthing centre. The health professionals there will test the drainage to see if it is amniotic fluid.

Amniotic fluid is normally a cloudy-white to an amber-straw colour. Let your health professional know right away if the leaking fluid:

• Is dark or greenish. Meconium (from a baby's first bowel movement) may be in the fluid.
• Smells bad. This could be a sign of infection in the uterus.
• Is bloody. Small streaks of blood are normal. But if the entire fluid is stained with blood, it could be a sign of a problem with the placenta.

Artificial rupture of the membranes to induce labour

To start (induce) or speed up labour, the doctor or midwife may rupture your membranes. This should only be done after your cervix has started to open (dilate) and the baby's head is firmly descended (engaged) in your pelvis. If the membranes are ruptured too early, the umbilical cord could slip down around or below the baby's head. (This is called a cord prolapse.) If the cord gets squeezed between the baby's head and the pelvis bones, the blood supply to the baby may be decreased or stopped.

To rupture your amniotic sac, your doctor or midwife inserts a sterile plastic hook into your vagina. It may look like a long crochet hook, or it may be a smaller hook attached to the finger of a sterile glove. The hook is used to pull gently on the amniotic sac until the sac breaks. This is usually not painful. You may feel a large gush of fluid. The uterus keeps making amniotic fluid until the baby's birth. So you may still feel some leaking, especially right after a hard contraction.