How does cervical length change during pregnancy?

The article is professionally consulted by Master, Doctor Ly Thi Thanh Nha - Department of Obstetrics and Gynecology - Vinmec International General Hospital Da Nang. Doctor Nha has strengths and experience in fetal malformation ultrasound, 3D, 4D fetal ultrasound.

Short uterus is one of the causes of premature birth and miscarriage, so ultrasound measuring cervical length is an important step to monitor health and to know if cervical length changes. during pregnancy or not.

The cervix is ​​the entrance to the uterus, which is the intermediate point between the uterus and the vagina. This organ plays an extremely important role during 40 weeks of pregnancy until the birth process. During pregnancy, the length of the cervix will increase, and at the same time, the cervix will thicken according to the change in the weight of the fetus.
When there is a fetus in the uterus, the cervix will close tightly thanks to the mucus plug to protect the uterine cavity always closed and sterile, ensuring the development of the fetus.
During labor, the cervix will shorten and dilate about 1 - 10cm so that the baby can come out of the uterus and be born.

For a normal developing girl, the cervix is ​​only about 30mm long, has a round and firm shape. However, during pregnancy, the length of the cervix will begin to change.
As the weight of the fetus increases, the cervix will lengthen to keep the baby firmly in the uterus. In the last weeks of pregnancy, the cervix shortens to make the birth process more convenient. After delivery, the length of the cervix will gradually return to normal. The length of the cervix during pregnancy is considered normal if it is between 30-50mm, less than 25mm is a short cervix.
To make an accurate diagnosis, pregnant women need an ultrasound to measure the length of the cervix through a vaginal transducer.

Short cervix can occur due to some of the following reasons:
Due to congenital factors, the woman has underdeveloped reproductive organs, malformed uterus, baby uterus ... cervicectomy or cone surgery. In addition, cervical length can change during pregnancy. This depends on the following factors:
Due to biological differences in women Complications from bleeding during pregnancy Infection or inflammation of the lining of the uterus Weak cervix not able to stretch properly.

A short cervix will not generally affect fertility or the chances of conception. However, this is the cause of some of the following phenomena:
Increased risk of preterm birth, miscarriage, early labor, the shorter the cervix, the higher the risk of preterm birth. The mother has some problems such as diabetes, high blood pressure, proteinuria...

To know exactly her condition, pregnant women need to have an ultrasound to measure the length of the cervix according to the doctor's prescription. In particular, transvaginal transvaginal ultrasound is a technique that is easy to observe and has higher accuracy than the transabdominal ultrasound method.
Transvaginal transvaginal ultrasound also helps doctors probe changes and dilation of the cervix ... Not only that, this method also ensures safety, comfort and does not increase the risk of infection even if the pregnant woman has premature rupture of membranes.
Thus, ultrasound measuring the length of the cervix is ​​an indispensable step to timely detect the condition of the short cervix, from which appropriate treatment measures can be taken. The second trimester of pregnancy is a period of strong fetal development. Pregnant women need:
Comprehensive fetal malformation screening by superior 4D ultrasound technique. Screening for gestational diabetes, avoiding many dangerous complications for both mother and baby. Control the mother's weight reasonably to assess the health status of the pregnant woman and the development of the fetus. Understand the signs of threatened early delivery (especially in those carrying multiple pregnancies or having a history of miscarriage or premature birth) so that they can receive timely treatment to maintain pregnancy. To protect mother and baby during pregnancy, Vinmec provides a comprehensive Maternity service to monitor the health status of mother and baby, periodical antenatal check-ups with leading Obstetricians and Gynecologists. enough tests, important screening for pregnant women, counseling and timely intervention when detecting abnormalities in the health of mother and baby.
For detailed information about all-inclusive maternity packages, please contact the hospitals and clinics of the Vinmec health system nationwide.