When the membrane ruptures, the fluid that surrounds the baby begins to leak out of the cervix. Amniotic fluid or liquor amnii is the nourishing and protecting liquid contained by the amniotic sac of a pregnant woman (Wikipedia)
The volume of amniotic fluid increases as the fetus grows. It reaches 800ml at 34 weeks of gestation. This amount declines to roughly 600 ml at 40 weeks gestation, which is usually when the baby is born. Amniotic fluid is "inhaled" and "exhaled" by the fetus. It plays a vital role in the development of internal organs, such as the lungs and kidneys.
Your biggest concern during the third trimester might be that your water will break in an undesirable situation, sending your amniotic fluid everywhere.
You might also imagine being in your office or in a grocery store when it happens. Usually water breaks spontaneously in about 12% of pregnant women. Most of the time, the rupture of the membrane happens during labor and sometimes the doctor will rupture it intentionally to stimulate the progress of labor.
In case your membrane ruptures, these are simple steps to follow before you go to the hospital:
Don’t panic. Take a deep breath and collect your thoughts.
Excuse yourself and find the closest bathroom and make your way there.
You don’t need to worry about the quantity of water getting out. It is a matter of having wet underwear of colorless and odorless amniotic fluid.
Get dry underwear if possible or change the pad or panty liner.
If the fluid looks green or brown or you feel something or see any of the umbilical cord at the vaginal opening, get medical help immediately.
Call your doctor. He will ask you to go to the hospital or to his office.
Contact your partner, a friend or any related family near you to assist you to the hospital.
Whatever happens, you should always be calm. Usually the rupture of the membrane doesn’t happen frequently by itself. If it happens to you, don’t worry, people are very friendly and helpful. At this stage of pregnancy it is very obvious to have your baby anytime.