Common Terms Used in Labor and Birth

Pregnancy comes with a whole new vocabulary. Let's start by learning a bit about your body and the terms used in pregnancy to discuss it. This is going to mean some terms and definitions. These terms and definitions will come in handy throughout your pregnancy and birth.


Definitions of Labor Terms

Black doctor examining pregnant patient's belly
Ariel Skelley/Blend Images/Getty Images

Braxton Hicks contractions: Painless, irregular contractions of the pregnant uterus, beginning during the first trimester and increasing in frequency as the pregnancy advances.

Cervix: The opening or passage between the vagina and the uterus.

Contraction: Rhythmic tightening of the uterus, usually causing the cervix to dilate and allow the passage of the baby. In labor, contractions get stronger, closer together and longer.

Dilation: The enlarging of the cervix to ten centimeters.

Effacement: The thinning of the cervix. Your cervix starts out being two inches long, and fifty percent effaced would be a one-inch thick cervix.

Labor: The period of contractions that change the cervix and ends with the birth of your baby.

Lightening: The baby changing positions in the uterus before labor, usually described as the baby "dropping." First-time moms can see this as soon as four to six weeks before their due date, while other moms will not notice this until labor begins.

Placenta: The organ within the pregnant uterus through which the fetus derives its nourishment, at term, it averages one-sixth the weight of the fetus; is disk-shaped, about 2.5 centimeters thick, and 17.5 centimeters in diameter.

Station: How far the baby is down in the pelvis. Measured in negative and positive numbers; negative five is a floating baby, zero station is said to be engaged in the pelvis, and plus five is crowning.

Uterus: Female reproductive organ that weighs two to three ounces and is about the size of a small woman's fist prior to pregnancy. During pregnancy, this organ becomes ten by 14 inches and weighs in at about two or three pounds. This is where a normal pregnancy takes place.


Important Terms in the Process of Labor

Dilation of the Cervix

Complete dilation is ten centimeters, this is when the cervix is fully open and the baby can further descend into the birth canal (vagina) during the pushing (second stage) of labor.

In addition to how far your cervix is open will be the effacement or thinning of your cervix (measured in percentages) and the ripeness of your cervix. Effacement and dilation happen together rather than one before the other for the majority of women.

Try this! If you feel the tip of your nose, this would be how an unripe cervix will feel, firm but fleshy. As it begins to soften or ripen, it will become more like the feeling of your earlobe (touch it!). When it is really soft and buttery it will be more like the inside of your cheek, very flexible and soft.

What Matters About the Cervix

For first-time moms, effacement is actually more important than dilation at first because the cervix will need to be soft to dilate. After you've had a baby previously the cervix seems to open more easily.

It is said that the average first-time mom will dilate just under a centimeter per hour once active labor has started and the mom having baby number two or more will dilate just over a centimeter per hour once active labor has begun.

However, there are no hard and fast rules about who will dilate how quickly that actually work. As you know babies can't read calendars and your cervix can't tell time. Some will dilate much more quickly and others more slowly.

Timing Contractions in Labor

Contractions are what most people focus on during labor. They can be helpful in determining where you are in labor, in fact, sometimes more so than your cervical dilation.

When you go to the hospital or birth center, when you call your practitioner, these decisions will usually be made based on what your contractions are doing. Timing contractions isn't that difficult. However, many people don't understand the basics.

You can figure out the three most important pieces of information gathered by timing contractions: how long the contractions last, how far apart they are, and what type of rest period you have in-between the contractions.

Some people prefer to use a contraction timing app.

You can use a watch with a second hand, a timer or a stopwatch to time the contractions. Some people choose to write them down, others do not. Do not chase her with the stopwatch, unless you don't mind being yelled at. It's also handy to time a few contractions and gets an idea of where they are and then stop until several hours have passed or there is a definite change in contractions, either closer together, stronger, longer or further apart.

Mucus Plug

The mucus plug is protective collection of mucus that has been in your cervical canal for many months protecting your body and baby from infection. As the cervix begins to efface and dilate little pieces of mucus can be seen in chunks or strings when wiping. Sometimes you will lose a large chunk at once, called the plug.

Because the cervix is so sensitive and the blood vessels are all right on the surface you can sometimes find that the plug has a pink or bloody tinge to it. Labor will usually begin possibly within days but also up to several weeks after the plug has been dislodged.


In first time moms, this can happen up to six weeks prior to the birth, though not always and frequently not until well into labor. Usually, moms will notice that they can breathe a bit more easily, heartburn may temporarily abate, though the trade-off is more frequent trips to the bathroom. This is simply the baby settling into the pelvis in preparation for its birthday!


This is where you get a burst of energy and feel like cleaning your house or washing all of the baby's clothes. I can't say it's not a sign of impending labor, but it's not a reliable sign. It's also one you can trick yourself into.

Just ask other moms about that part, one mother actually hung 14 windows of plastic wrap and did the heat application to seal the windows for winter in her ninth month, hoping it would put her into labor! You can't force nesting, it simply happens, if it's going to happen.


Unlike the Braxton Hicks contractions you've had previously you may have periods of contractions that do change your cervical dilation and effacement but stop without warning. This is why we tell women to use these practice bouts for just that purpose.

What can you do to make life more comfortable during contractions? What happens when you change position? Which relaxation techniques work best at this point?

Other Signs

Other pre-labor signs can include:

  • Loose stools
  • An upset stomach
  • Diarrhea
  • Weight loss
  • Slight increase in blood pressure

Many women will tell you that they made several trips to the hospital or spent hours on the phone with their practitioner or doula trying to determine if this was real labor or false labor.

First of all. let me say that there is no such thing as false labor. Certainly, there are periods of contractions that do not end with the birth of the baby, but they are beneficial for reasons that we may not be able to measure like dilation. Perhaps they are helping the baby rotate to a better position or there is another benefit.

Here is a handy chart to tell if this is the real thing or not:

False Labor
  • Contractions don't get closer together.

  • Contractions don't get stronger.

  • Contractions tend to be felt only in the front.

  • Contractions don't get longer.

  • Walking has no effect on the contractions.

  • Cervix doesn’t change with contractions.

True Labor
  • Contractions do get closer together.

  • Contractions do get stronger.

  • Contractions tend to be felt all over.

  • Contractions do last longer.

  • Walking makes the contractions stronger.

  • Cervix opens and thins with contractions.

A Word From Verywell

Don't worry if you wind up calling your doctor or midwife a few times. Even the most experienced mothers can be fooled by contractions.

6 Sources
Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Hanley GE, Munro S, Greyson D, et al. Diagnosing onset of labor: A systematic review of definitions in the research literature. BMC Pregnancy Childbirth. 2016;16:71. doi:10.1186/s12884-016-0857-4

  2. Thangaraj JS, Habeebullah S, Samal SK, Amal SS. Mid-pregnancy ultrasonographic cervical length measurement (a predictor of mode and timing of delivery): An observational study. J Family Reprod Health. 2018;12(1):23-26.

  3. Whitburn LY, Jones LE, Davey MA, Small R. The meaning of labour pain: How the social environment and other contextual factors shape women's experiences. BMC Pregnancy Childbirth. 2017;17(1):157. doi:10.1186/s12884-017-1343-3

  4. Langen ES, Weiner SJ, Bloom SL, et al. Association of cervical effacement with the rate of cervical change in labor among nulliparous women. Obstet Gynecol. 2016;127(3):489-95. doi:10.1097/AOG.0000000000001299

  5. Černohorská P, Vitásková H, Kokrdová Z, Hájek Z, Koucký M, Pařízek A. Cervical cerclage - history and contemporary use. Ceska Gynekol. 2019;84(1):55-60.

  6. Carlsson IM. Being in a safe and thus secure place, the core of early labour: A secondary analysis in a Swedish context. Int J Qual Stud Health Well-being. 2016;11:30230. doi:10.3402/qhw.v11.30230

Additional Reading
  • Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Sixth Edition.
  • The Labor Progress Handbook. Simkin, P and Ancheta, R. Wiley-Blackwell; 2 edition.

By Robin Elise Weiss, PhD, MPH
Robin Elise Weiss, PhD, MPH is a professor, author, childbirth and postpartum educator, certified doula, and lactation counselor.