Contractions During Pregnancy: What to Expect
Table of Contents
Topic Overview
Credits
Topic Overview
Regular contractions may mean that your uterine muscle is tightening (Braxton
Hicks contractions) or that you are in labour. It may be hard to tell the difference
between Braxton Hicks contractions and true labour. 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 labour pains continue or
increase with activity.
Are felt more during rest.
Preterm labour
The length of a normal pregnancy is 37 to 42 weeks, measured from the date of
the woman's last menstrual period. Preterm labour occurs before the 37th week
of pregnancy. Before 20 weeks, preterm labour that leads to delivery is a
miscarriage (spontaneous abortion).
Preterm labour is diagnosed in a woman who is 20 to 37 weeks pregnant and
has regular uterine contractions. This means 4 or more in 20 minutes, or about 8
or more in 1 hour.
Call your doctor if you have had regular contractions for an hour. This means
about 4 or more in 20 minutes, or about 8 or more within 1 hour, even after you
have had a glass of water and are resting.
Early labour
Early labour 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 labour, the cervix opens (dilates) to about 3 cm (1.2 in.).
First-time mothers may have many hours of early labour without the cervix
dilating. You may go to the hospital and be sent home again until you begin
active labour or your water breaks (rupture of the membranes).
Active labour
The first stage of active labour starts when the cervix is about 3 cm (1.2 in.) to 4
cm (1.6 in.) dilated and 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), labour
becomes really intense.
Compared to early labour, the contractions during the first stage of labour:
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 labour. Now is the time to be at or
go to the hospital or birthing centre. If your bag of waters (amniotic sac) has not
broken before this, it may now. If you have taken a labour class and learned how
to do special breathing during contractions, you will want to begin the special
breathing now.
Credits for Contractions During Pregnancy: What to Expect
By
Healthwise Staff
Primary Medical
Reviewer
William H. Blahd, Jr., MD, FACEP - Emergency
Medicine
Specialist Medical
Reviewer
David Messenger, MD
Last Revised
August 24, 2010
Cervical Effacement and Dilatation
Table of Contents
What are effacement and dilatation?
Credits
Appendix
Topic Images
o Cervical effacement
What are effacement and dilatation?
As labour nears, the cervix begins to thin or stretch (efface) and open (dilate) to
prepare for the passage of the baby through the birth canal (vagina). How fast
the cervix thins and opens varies from woman to woman. In some women, the
cervix may efface and dilate slowly over a period of weeks. A first-time mother
often will not dilate until active labour begins.
Late in your pregnancy, your health professional may manually check (wearing
sterile gloves) how much your cervix has effaced and dilated.
Effacement
As the baby's head drops down into the pelvis, it pushes against the cervix and
causes the cervix to relax and thin out, or efface.
See a picture of cervical effacement (See figure 1 in appendix).
Throughout your pregnancy, your cervix has been closed and protected by a plug
of mucus. When the cervix effaces, the mucus plug is loosened and passes out
of the vagina. The mucus may be tinged with blood. This passage of the mucus
plug is called "show" or "bloody show." You may or may not notice when the
mucus plug passes.
Effacement is described as a percentage. For example, if your cervix is not
effaced at all, it is 0% effaced. If the cervix has completely thinned, it is 100%
effaced.
Dilatation
After the cervix begins to efface, it will also begin to open (cervical dilatation).
Cervical dilatation is expressed in centimetres from 0 to 10. Zero means that the
cervix is closed, and 10 means that it is completely dilated.
Credits for Cervical Effacement and Dilatation
By
Healthwise Staff
Primary Medical
Reviewer
Kathleen Romito, MD - Family Medicine
Primary Medical
Reviewer
Sarah Marshall, MD - Family Medicine
Primary Medical
Reviewer
Donald Sproule, MD, CM, CCFP, FCFP - Family
Medicine
Specialist Medical
Reviewer
Kirtly Jones, MD - Obstetrics and Gynecology
Last Revised
February 18, 2010
Topic Images
Figure 1
Cervical effacement
As labour nears, the fetus's head drops down into the pelvis and pushes against
the cervix. The cervix begins
