Some women can develop a weakness in the neck of the womb (cervix), which causes miscarriage (loss of pregnancy) between 12 and 24 weeks (3 to 6 months) of pregnancy. The cause is often not found despite extensive investigation.
The weakness is amenable to surgery during pregnancy, usually between 10 and 14 weeks of pregnancy, by placing a stitch around the neck of the womb. This allows pregnancy in many cases to continue beyond 24 weeks (viability or ability of the baby to survive outside the womb).
Women who develop this weakness do not know they have it until the neck of the womb has started to open after 3 months of pregnancy. There is minimal pain and often no bleeding down below. The first symptom is often an increased clear or lightly bloodstained vaginal discharge, which alerts the woman to attend her hospital. At this time a gentle internal examination can reveal the neck of the womb to be opening with visible membranes (bag of fluid that surrounds baby), which have fallen down through the open neck of womb. It is too late at this stage to do anything about the situation, and many women miscarry shortly afterwards.
Following late pregnancy loss, a series of investigations may be done to exclude other contributing causes, such as “sticky blood” (antiphospholipid syndrome) or overgrowth of vaginal bacteria (bacterial vaginosis). In addition, an operation to explore the shape and size of the neck of womb and lining of womb may be undertaken (hysteroscopy). This operation may involve a general anaesthetic and admission to hospital for the day.
After all investigations are complete, you will find out what should happen during your next pregnancy. This would involve putting in a stitch in the neck of the womb usually between 10 and 12 weeks of pregnancy (vaginal stitch / cervical suture).
The stitch is placed at the neck of the womb from down below and uses a general anaesthetic with admission for the day. The procedure lasts about 30 minutes and is not usually associated with side effects such as bleeding. It very rarely causes haemorrhage (heavy bleeding), miscarriage or infection.
Once the stitch is in place you will probably have a scan (after 16 weeks) to examine the neck of the womb to assess whether there is evidence of opening (funnelling) and to measure the length of the cervix (see diagram). The doctors want to know if the neck of the womb is getting shorter than expected and if the internal neck of the womb is opening.