Do you know the typical signs of labor? Understand the changes your body will go through as you prepare to give birth.

By Mayo Clinic Staff

In the movies, babies are often born quickly and in dramatic fashion. The mother doubles over from the pain of a single contraction and suddenly the baby appears. In reality, however, labor usually takes time — and the early signs of labor can be subtle. Here's what you need to know about the common signs of labor.

Before labor, the lower part of your uterus called the cervix is typically 3.5 cm to 4 cm long. As labor begins, your cervix softens, shortens and thins (effacement). You might feel uncomfortable, but irregular, not very painful contractions or nothing at all.

Effacement is often expressed in percentages. At 0 percent effacement, the cervix is at least 2 centimeters (cm) long, or very thick. Your cervix must be 100 percent effaced, or completely thinned out, before a vaginal delivery.

Another sign of labor is your cervix beginning to open (dilate). Your health care provider will measure the dilation in centimeters from zero (no dilation) to 10 (fully dilated).

At first, these cervical changes can be very slow. Once you're in active labor, expect to dilate more quickly.

During pregnancy, a thick plug of mucus blocks the cervical opening to prevent bacteria from entering the uterus. During the late third trimester, this plug might be pushed into your vagina. You might notice an increase in vaginal discharge that's clear, pink or slightly bloody. This might happen several days before labor begins or at the start of labor.

If vaginal bleeding is as heavy as a normal menstrual period, however, contact your health care provider immediately. Heavy vaginal bleeding could be a sign of a problem.

You might wake up one morning feeling energetic, eager to fill the freezer with prepared meals, set up the crib and arrange your baby's outfits according to color. This urge is commonly known as the nesting instinct.

Nesting can begin at any time during pregnancy but for some women it's a sign that labor is approaching. Do what you must, but don't wear yourself out. Save your energy for the harder work of labor ahead.

Lightening is the term used to describe when the baby's head settles deep into your pelvis. This might cause a change in the shape of your abdomen. This change can happen anywhere from a few weeks to a few hours before labor begins.

The amniotic sac is a fluid-filled membrane that cushions your baby in the uterus. At the beginning of or during labor, your membranes will rupture — also known as your water breaking.

When your water breaks you might experience an irregular or continuous trickle of small amounts of watery fluid from your vagina or a more obvious gush of fluid. If your water breaks — or if you're uncertain whether the fluid is amniotic fluid, urine or something else — consult your health care provider or head to your delivery facility right away. You and your baby will be evaluated to determine the next steps.

Once your amniotic sac is no longer intact, timing becomes important. The longer it takes for labor to start after your water breaks — if it hasn't started already — the greater you or your baby's risk of developing an infection. Your health care provider might stimulate uterine contractions before labor begins on its own (labor induction).

During the last few months of pregnancy, you might experience occasional, sometimes painful, contractions — a sensation that your uterus is tightening and relaxing. These are called Braxton Hicks contractions.

To tell the difference between Braxton Hicks contractions and the real thing, consider these questions:

  • Are the contractions regular? Time your contractions from the beginning of one to the beginning of the next. Look for a regular pattern of contractions that get progressively stronger and closer together. False labor contractions will remain irregular.
  • How long do they last? Time how long each contraction lasts. True contractions last about 30 to 70 seconds.
  • Do the contractions stop? True contractions continue regardless of your activity level or position. With false labor, the contractions might stop when you walk, rest or change position.

Remember, no one knows for sure what triggers labor, and every woman's experience is unique. Sometimes it's hard to tell when labor begins.

Don't hesitate to call your health care provider if you're confused about whether you're in labor. Preterm labor can be especially sneaky. If you have any signs of labor before 37 weeks — especially if you also experience vaginal spotting — consult your health care provider.

If you arrive at the hospital in false labor, don't feel embarrassed or frustrated. Think of it as a practice run. The real thing is likely on its way.

June 18, 2016