A woman’s cervix is the neck of the uterus, which extends into their vagina. This narrow tube or canal remains open, just big enough to allow sperms to enter or to let blood flow out during menstruation. When a woman becomes pregnant, this narrow opening is sealed with a mucus plug, which forms a protective barrier for the canal. During pregnancy, a lot of changes occur in the cervix, as it softens, becomes longer, then shortens, dilates and becomes thinner as pregnancy progresses. Why do these things happen, and what is the role of the cervix during pregnancy? Here is some information to answer this question about your reproductive anatomy.
Does the Position of My Cervix Change During Pregnancy?
During pregnancy, the position of your cervix will change, but this happens at various times for different women.
The cervix rises a little bit and becomes softer as early as the 12th day after ovulation or a bit later, when your home pregnancy test becomes positive. For some women, this occurs just before they are expecting their period, while for others it happens just when their pregnancy is confirmed by a doctor.
Thickening of the cervix is usually the first change observed, since it produces more glandular cells that form the mucus plug. It may also become inflamed, appearing red on examination, and sometimes allowing some bleeding (spotting).
Thickening of the cervix serves to protect the uterus, but when your date of delivery is near, it starts to prepare for childbirth. Your cervix will slowly dilate, which causes the mucus plug to be lost. This may occur a few weeks before your expected date of delivery, but in other women, it may happen just as labor commences. However, physical examination alone cannot provide information if you are close to delivery.
What About the Length of Cervix During Pregnancy?
The cervix is rigid and closed before pregnancy, but it softens and elongates during pregnancy. However, during labor, the cervix shortens and dilates to allow the passage of your baby.
Cervical shortening before 37 weeks of pregnancy increases your risk of giving birth to a premature baby. A baby is usually born about 38 weeks after conception. Although the cervix gradually softens and effaces (decreases in length) as the baby grows bigger in the uterus, it does not open or dilate until you are ready to give birth. If your cervix is short before the 37th week, you may go into preterm labor. If premature birth occurs even earlier, your baby may have greater health risks.
Factors that influence the length of your cervix during pregnancy include:
- Biological differences among women
- Uterine activity of unknown origin
- Overdistended or overstretched uterus
- Complications related to bleeding during your pregnancy
- Weak cervix (incompetent cervix)
Signs and symptoms that you are experiencing preterm labor include frequent or regular uterine contractions, vaginal spotting, pelvic pressure, or constant low back ache. Consult your health care provider to determine by pelvic examination, if your cervix is beginning to open. An ultrasound examination may be done to measure the length of your cervix.
The health care provider will explain the risks and benefits of treatments to try to stop your preterm labor. However, if you are not in active labor but you are still in early pregnancy and in danger of premature labor, your doctor may suggest that you have a cervical cerclage. This surgical procedure closes the cervix by stitching it with strong sutures. This is usually done in women who have a history of giving birth prematurely and has an ultrasound showing the cervix beginning to open.
Other forms of treatment involve the use of a hormone (progesterone) or a pessary (a silicone device), which is placed around your cervix to prevent premature birth.
If you have a history of premature birth and are concerned about the length of your cervix during pregnancy, consult your doctor to know more about promoting healthy pregnancy.
Will Cervix Insufficiency Affect My Pregnancy?
If your cervix is shortening (effacing) and opening (dilating) before your baby has reached full term, then you may have cervical insufficiency, a condition that can lead to premature birth. It can happen during your second trimester or early in your third trimester of pregnancy. As your baby grows, her weight puts more pressure on your cervix, and if it is soft and weak or abnormally short, you may give birth soon, even if there are no contractions or symptoms of labor.
How to Deal With Cervical Insufficiency During Pregnancy
A weak or incompetent cervix is usually treated with a surgical procedure called cerclage. It involves sewing around the cervix to keep it closed and to reinforce it. It is usually done between the 14th and 16th week of pregnancy. Sutures are removed between the 36th and 38th weeks to avoid problems during labor. It does not result in spontaneous labor and delivery.
However, you may not be eligible for this procedure if:
- Your cervix is irritated or inflamed
- Your cervix has dilated to 4 cm
- Your membranes have already ruptured
Cervical cerclage can have some complications, which include rupture of the uterus, maternal bleeding or hemorrhage, rupture of the bladder, laceration of the cervix, premature rupture of membranes, and preterm labor. However, there is minimal risk of these complications and most doctors believe that doing a cerclage is life-saving treatment that is worth taking the risk.