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The cervix is the cylindrical part of the uterus that connects the uterus to the vagina. Before pregnancy, the cervix is closed, long, and firm. Its main role is to secrete fluids that help sperm travel from the vaginal canal to the uterus.
Natalia Viarenich, MD
Updated February 23 2021
The cervix is typically around 3–5 centimeters long and gradually shortens during pregnancy. However, sometimes the cervix is shorter than average, which may cause issues during pregnancy.
What does a “short cervix” mean?
The cervix has an internal and an external opening (also called the internal os and external os). The internal os opens into the uterus, and the external os opens into the vagina. During pregnancy, the cervical ossa close to keep the fetus in the uterus and then open when it’s time for delivery.
Over the course of a pregnancy, the cervix shortens and becomes softer to make delivery possible. Some people naturally have a shorter cervix. As their cervix shortens throughout their pregnancy, it may become too short too soon, which increases the risk of preterm labor and premature birth. A short cervix is less than 25 millimeters in length at 18–24 weeks’ gestation. Health care providers measure the length of the cervix with an ultrasound scan.
What causes a short cervix?
The main cause for a short cervix during pregnancy is an insufficient or incompetent cervix. During pregnancy, the baby grows and becomes heavier, pressing on the cervix. If the cervix is short, the pressure from the baby may cause it to open before the baby is ready to be born. This condition is known as an insufficient or incompetent cervix.
Most pregnancy losses in the first trimester are due to chromosomal abnormalities, but an incompetent cervix is the cause of many losses during the second trimester. Insufficient cervix is not very common, however. Only one in 100 pregnancies might result in an incompetent cervix.
In addition to a short cervix, one or more of the following conditions might lead to an insufficient cervix:
- An earlier cervix surgery
- Cervical trauma
- Malformed cervix as a result of a birth defect
- Trauma to the cervix from a miscarriage or abortion
- Diethylstilbestrol (a synthetic estrogen) exposure in utero
- Curettage (removing tissue from the inner lining of the uterus)
- Loop electrocautery excision procedure, used to treat cervical dysplasia
- Uterine anomalies or cervical lacerations with vaginal delivery
Short cervix symptoms
Although often asymptomatic, some mild short cervix symptoms are possible. The symptoms usually appear between 14 and 20 weeks of pregnancy and include:
- Pelvic pressure
- Abdominal cramps
- Change in volume, color, and consistency of vaginal discharge
- Light vaginal spotting or bleeding
- Contractions similar to Braxton-Hicks
Short cervix: possible complications
When the cervix is short, the risk of premature labor and pregnancy loss rises. This is because the cervix might not stay closed for as long as it’s supposed to during pregnancy. Those with a short cervix during pregnancy are more likely to have preterm labor than those with a longer and thicker cervix.
There is treatment for a short cervix. Health care providers may recommend a few different methods to help avoid premature birth. Regular prenatal care makes it possible for a health care provider to discover and treat issues associated with a short cervix in a timely manner.
Short cervix diagnosis
A short cervix can only be detected during pregnancy. A short cervix can’t be diagnosed by a manual exam, but a physical exam can help the health care provider see if the amniotic sac has begun to protrude through the opening (prolapsed fetal membranes). A transvaginal ultrasound is the most reliable way to diagnose a short cervix.
During an ultrasound, a health care provider will measure the cervical length. In a typical pregnancy, the cervix is usually between 3–5 centimeters long (30 to 50 millimeters). The risk of premature birth is greatest when the cervix is less than 2.5 centimeters long. Early detection of a short cervix during pregnancy can help prevent preterm birth and begin treatment before it causes any complications.
How to manage a short cervix
The risk of premature birth and pregnancy loss due to a short cervix can be concerning.
There are ways to manage the risk of a short cervix and prolong the pregnancy. Treatment for a short cervix includes:
- Progesterone: Progesterone is a hormone that is used to prevent contractions and support a pregnancy until it reaches full term. It’s possible to receive the hormone as a weekly injection, as a daily vaginal medication, or vaginal progesterone pessaries until around 34 to 36 weeks. A health care provider may prescribe it in the second trimester or earlier.
- Arabin pessary: The Arabin pessary is another way to reduce the chances of premature pregnancy. It’s a silicone ring that is inserted into the vagina to hold the cervix closed. This is not a surgical procedure, and the placement of the ring is done by an obstetrician. The Arabin pessary placement can increase the risk of an infection.
- Cervical stitch/cerclage: During a cervical cerclage, a stitch is placed in the cervix to help it to stay closed. Cerclage is associated with an 85 to 90 percent successful pregnancy rate. The cerclage is maintained until 36 to 38 weeks of pregnancy or until labor. This procedure is offered to those who have had one or more premature deliveries, late miscarriages, or cervical surgery in the past, and an ultrasound shows that the cervix is opening.
If the diagnosis of a short cervix is made, betamethasone may be used between 24 and 34 weeks of gestation to improve newborn outcomes. Strict bed rest may be recommended as a precautionary measure.
Health care providers will generally also suggest regular monitoring and a consultation with a physician who specializes in high-risk pregnancies. In this way, any issues with a short cervix during pregnancy can be found and treated early.
What should I do if I have a short cervix during pregnancy? ›
There are generally two treatment options for a short cervix. For some women, a doctor may recommend a cerclage. This is a stitch in the cervix that reinforces it, reducing the risk of pregnancy loss or preterm labor. Doctors advise against cerclage for women with twin or other multiple pregnancies.What is the reason for short cervix? ›
Causes. The main causes of a short cervix and cervical funneling include heredity, trauma, abnormalities of the cervix or uterus, or having an insufficient cervix (also called incompetent cervix). An insufficient cervix is when your cervix opens or dilates too early and is a common cause of premature birth.Can I go full term with a short cervix? ›
Only 2% of low-risk pregnancies at 22 to 24 weeks of gestation will have a CL shorter than 15 mm, but 60% of these women will deliver before 28 weeks of gestation and 90% will deliver before 32 weeks.How early can baby be born with a short cervix? ›
The risk of spontaneous preterm birth in asymptomatic women with a short cervix (≤25 mm) at 23-28 weeks' gestation.Can you have a healthy baby with a short cervix? ›
If you have a short cervix, you have a 1-in-2 chance (50 percent) of having a premature birth, before 37 weeks of pregnancy. So if you have a short cervix and you're pregnant with just one baby, your health care provider may recommend these treatments to help you stay pregnant longer: Cerclage.Does short cervix mean high risk? ›
During pregnancy, the length of the cervix might shorten too soon, increasing the risk of preterm labor and premature birth. Preterm labor is labor that begins between 20 weeks and 36 weeks and 6 days of pregnancy. The earlier premature birth happens, the greater the health risks for the baby.What should I avoid with a short cervix? ›
Is there anything you should do? Due to your increased risk of having your baby early we recommend that you avoid high impact exercise, prolonged standing (for more than four hours). We also advise against vaginal douching and sexual intercourse until 34 week gestation.How can I strengthen my cervix? ›
Vitamin C. Vitamin C is perhaps one of the most well-known vitamins, famous for its role in immune health. * But vitamin C-rich foods can also help support cervical health. While the list of vitamin C foods is seemingly endless, you'll find mangoes, bell peppers, citrus fruits, kiwi, and strawberries near the top.How should I sleep with a short cervix? ›
Bed rest. Sometimes, a doctor may recommend bed rest (or pelvic rest) and continued monitoring for a short cervix. This can mean anything from no sex or strenuous activity to full-on, only-get-up-to-pee-and-eat bed rest. However, it's important to note that strict bed rest has not been proven to prevent preterm labor.How quickly can cervical length change? ›
The cervix exhibits minimal changes from 11 to 24 weeks for most women, although the shortening is more prominent in women with a history of cervical surgery or preterm delivery. First-trimester cervical length measurement can predict preterm delivery.
Is short cervix genetic? ›
You may have been born with a naturally weak or short cervix and this may be genetic.Can bed rest increases cervix length? ›
Based on these results, we conclude that therapeutic cerclage with bed rest increases cervical length and that bed rest alone has a variable but, on average, negligible effect on cervical length.What foods heal the cervix? ›
- A healthy diet with these antioxidant vitamins can help maintain a healthy cervix.
- Vitamin A packed foods include Sweet potato, carrots, spinach, pumpkin, mangoes, and cantaloupe.
The B vitamin known as folate is commonly prescribed to women to ensure the health of their reproductive system during childbearing age. So it follows that folate could also help keep the cervix in shape. For a double dose, pair spinach with a grain such as rice that's been folate enriched.What are signs of a weak cervix? ›
- A sensation of pelvic pressure.
- A new backache.
- Mild abdominal cramps.
- A change in vaginal discharge.
- Light vaginal bleeding.
If you keep standing / sitting once contractions begin, the contractions can become regular. Contractions that become regular can lead to preterm labor. As contractions become regular, the cervix begins to thin out and open.Does walking put pressure on cervix? ›
The simple act of walking during pregnancy may help draw the baby down into your pelvis (thanks to gravity and the swaying of your hips). The pressure of the baby on your pelvis may then prime your cervix for labor — or may help labor progress if you've already felt some contractions.Can you feel cervix shortening? ›
You're unlikely to feel your cervix shortening and getting thinner. However, it may be happening if: You feel fullness in your pelvis from your baby's head after they drop. The pressure could be ripening your cervix.What is the chance of preterm labor with a short cervix? ›
In low-risk women, there is an increased risk of preterm labor as cervical length decreases. However, only 25% of low-risk women with a short cervix deliver early3 . In a high-risk population, 75% with a cervical length ≤ 25 mm at 16-18 weeks' will deliver prematurely11.How can I prevent preterm labor with a short cervix? ›
Cerclage: In this procedure, stitches close a woman's cervix to help prevent preterm birth. Doctors may recommend cerclage (sair-KLAZH) for women who have had premature babies or miscarriages, who have a short cervix, or who have a cervix that begins to open (dilate) too early.
Can cervical length increase with bed rest? ›
Based on these results, we conclude that therapeutic cerclage with bed rest increases cervical length and that bed rest alone has a variable but, on average, negligible effect on cervical length.What can you do for a short cervix? ›
For a cervix that's under 25 millimeters long, progesterone hormone therapy can help prevent premature birth and reduce complications if you have a short cervix and are carrying just one baby. A vaginal suppository starting at the time of diagnosis and stopping by 37 weeks could be prescribed.