Contractions During Pregnancy: What to Expect
Regular contractions may mean that your uterine muscle is tightening (Braxton Hicks contractions) or that you are in labor. It may be hard to tell the difference between Braxton Hicks contractions and true labor. If there is any doubt, call your doctor.
Braxton Hicks contractions
During the second and third trimesters of pregnancy, you may have episodes when your belly tightens and becomes firm to the touch, then relaxes. These are episodes of tightening (contraction) of the uterine muscles called Braxton Hicks contractions. These normal contractions may be mild, or they may be strong enough to make you stop what you are doing.
Braxton Hicks contractions can begin as early as the 20th week of pregnancy, but most often they start between the 28th and 30th week.
Braxton Hicks contractions can occur often during the 9th month, such as every 10 to 20 minutes.
Braxton Hicks contractions:
- Usually go away during exercise or activity. True labor pains continue or increase with activity.
- Are felt more during rest.
The length of a normal pregnancy is 37 to 42 weeks, measured from the date of the woman's last menstrual period. Preterm labor occurs before the 37th week of pregnancy. Before 20 weeks, preterm labor that leads to delivery is a miscarriage (spontaneous abortion).
Preterm labor is diagnosed in a woman who is 20 to 37 weeks pregnant and has regular uterine contractions. This means about 6 or more contractions in 1 hour.
Call your doctor if you have had regular contractions for an hour, even after you have had a glass of water and are resting.
Early labor is often the longest part of the birthing process, sometimes lasting 2 to 3 days. Uterine contractions:
- Are mild to moderate and last about 30 to 45 seconds. You can keep talking during these contractions.
- May be irregular, about 5 to 20 minutes apart, and may even stop for a while.
In early labor, the cervix opens (dilates) to about 3 cm (1.2 in.).
First-time mothers may have many hours of early labor without the cervix dilating. You may go to the hospital and be sent home again until you begin active labor or your water breaks (rupture of the membranes).
The first stage of active labor starts when the cervix is about 3 cm (1.2 in.) to 4 cm (1.6 in.) dilated. This stage is complete when the cervix is fully dilated and the baby is ready to be pushed out. During the last part of this stage (transition), labor becomes really intense.
Compared to early labor, the contractions during the first stage of labor:
- Are more intense.
- Occur more often, about every 2 to 3 minutes.
- Last longer, about 50 to 70 seconds.
You may feel restless or excited during active labor. Now is the time to be at or go to the hospital or birthing center. If your bag of waters (amniotic sac) has not broken before this, it may now. If you have taken a labor class and learned how to do special breathing during contractions, you will want to begin the special breathing now.
Current as of: February 23, 2022
Author: Healthwise Staff
William H. Blahd Jr. MD, FACEP - Emergency Medicine
Adam Husney MD - Family Medicine
Elizabeth T. Russo MD - Internal Medicine
Kathleen Romito MD - Family Medicine
Kirtly Jones MD - Obstetrics and Gynecology