Cervical insufficiency (also known as incompetent cervix/cervical weakness)

The cervix is the small canal at the base of the womb that connects it to the vagina. It is also known as the neck of the womb.

Cervical stitch infographic

When a normal pregnancy reaches full term the cervix begins to dilate (open) and efface (shorten) to allow the baby out. Cervical insufficiency (or cervical weakness/incompetent cervix) is the term for when this happens early without labour or contractions in the second trimester. It can lead to the waters breaking and late miscarriage or premature birth.

Causes of cervical insufficiency

The cervix may be naturally weak, or the weakness may have been caused during previous pregnancy, previous obstetric trauma or childbirth.

Research shows that infection caught during pregnancy is linked to the cervix shortening and opening but it is not clear whether the infection causes the cervix to open or the cervix is opening because of the infection

Am I at risk of cervical weakness?

You are considered to be at higher risk of having cervical weakness if you have previously had one or more premature births or miscarriages during the second trimester or third trimester. Previous cervical biopsy, or other surgery involving the cervix is also a risk factor.

Treatment for cervical weakness - the cervical stitch/cerclage

If your healthcare team are concerned about your cervix, you may be offered an internal scan to look at the neck of the womb more closely during your pregnancy.

If you have had one or more premature babies/late miscarriages or cervical surgery in the past and your cervix is getting shorter in early pregnancy, or if you have had a number of premature deliveries but your cervix has not shortened, you may be offered a cervical stitch (also known as a cerclage or cervical suture).

This is a special stitch that is put around your cervix to keep it closed. It can be put in before or during pregnancy. After the operation you may have some cramps similar to period pains, and you may have bleeding and spotting for a few days.

The stitch is usually removed at around 37 weeks so you can give birth. If you go into labour before then, it will be taken out immediately.

The cervical stitch can be put at the top (abdominal) or bottom (vaginal) of your cervix. It is usually put in under regional anaesthetic, such as an epidural, which means you are awake but can't feel anything.

The research on the effects of the stitch is still uncertain but so far it shows that most women who have had cerclage have carried their babies to full term. In a small number of women however the stitch does not prevent the waters from breaking and causing a miscarriage or preterm birth. Other rare complications include infections or excessive bleeding.


  1. NICE (2007) Laparoscopic cerclage for the prevention of recurrent pregnancy loss due to recurrent miscarriage, National Institute of Health and Clinical Excellence
  2. J David, Steer P et al (2010) High risk pregnancy, management options, Elsevier Saunders
  3. Cockwell HA, Smith GN (2005) Cervical incompetence and the role of emergency cerclage. J Obstet Gynaecol Can. 2005 Feb;27(2):123-9
  4. Liddiard A, Bhattacharya S (2011) Elective and emergency cervical cerclage and immediate pregnancy outcomes: a retrospective observational study, JRSM Short Rep. Nov 2011; 2(11): 91.


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Last reviewed on June 1st, 2014. Next review date June 1st, 2017.

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  • By Midwife @Tommys on 18 Aug 2016 - 11:24

    Hi, I am so sorry to hear what you have been through in your last pregnancy and losing your little boy. It is completely understandable that you are feeling so anxious and terrified in this pregnancy. Cervical length is not measured as a routine, only done if there is deemed to be a risk of you labouring early in pregnancy. If there was any risk this should have been identified by the midwife at your booking and a plan put in place for you. If you would like to talk further about this or would like some more information then please do call a midwife on 0800 074 800 or email midwife@tommys.org

  • By Anonymous (not verified) on 18 Aug 2016 - 06:11

    Hello. Is cervical length something they will check at the anomoly scan at 16 or 20 weeks. Is it worth paying for the scan private if not. I have no history of miscarriage. We just had to terminate our last pregnancy at 17 weeks because our boy had a severe heart condition. I am terrified of losing this baby too. Thank you for your help.

  • By Midwife @Tommys on 15 Aug 2016 - 14:43

    Hi, It sounds as if you have had a difficult time with the miscarriages and it takes time to recover. However, if you have pelvic pain I would suggest you see your GP or you could call us on 0800 0147 800.

  • By Midwife @Tommys on 15 Aug 2016 - 10:54

    Hi, So sorry to hear about your two miscarriages. Even though about 1:4 pregnancies ends in miscarriage the reasons are sometimes never known and your miscarriage may or may not be associated with cervical problems. Please feel free to contact us at Tommy's on 0800 0147 800 where we may be able to advise you.

  • By Anonymous (not verified) on 12 Aug 2016 - 17:58

    I had two missriage.my water burst when is not time for delivery at sixteen weeks.pls I need answer.

  • By Midwife @Tommys on 3 Aug 2016 - 12:44

    Hi, thank you for your message. As your pregnancy progresses the growing baby exerts pressure on your organs and this, of course includes your pelvic floor. Women often complain of pressure in the lower back, heaviness in the lower abdomen, vaginal pressure and sometimes rectal. This may be due to the weight gain and position of your baby. However with additional symptoms it may also be a sign of preterm labour.
    Please feel free to call us at Tommy's 0800 0147 800 as each pregnancy is different.

  • By Anonymous (not verified) on 3 Aug 2016 - 11:47

    I don't have a history of mid trimester miscarriage but I feel a lot of pressure at the moment and it feels like the baby is trying to escape. That is the only way I can explain this feeling. It's making me very anxious about possible incompetent cervix. It's my second baby and I had no complications with my first. No vaginal pressure until I delivered. I hate this feeling and I'm driving myself insane.

  • By Anonymous (not verified) on 4 Jul 2016 - 05:37

    Evn i lost my prrgnency in 21weeks coz of cervic opened, doctor said its impossible to put stitch coz opened cervix centimeter is more, so thy terminated my baby. It was boy

  • By Deirdre@Tommy's on 13 May 2016 - 09:59

    This one is difficult to answer without knowing the specifics of your case. Would you like to call our midwives on 0800 0147 800? They should be able to help. They are on the line Mon-Fri, 9-5pm.
    Hope this helps,

  • By Anonymous (not verified) on 12 May 2016 - 21:40

    I want to know if a cervix can grow strong again after being damaged.

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