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All women who choose to give birth at St George’s University Hospitals NHS Foundation Trust are offered an appointment to have an early scan, between weeks 11-14. It gives you the opportunity to see some visual evidence of your pregnancy and we consider the scan to be crucial for the following reasons:

  • To accurately date the pregnancy. This is particularly important for women who do not know the date of their last menstrual period, have an irregular cycle or have conceived whilst breastfeeding or soon after stopping the pill
  • To diagnose multiple pregnancy. Approximately 2% of natural conceptions and 10% of assisted conceptions result in a multiple pregnancy
  • To diagnose early pregnancy failure. Sadly, approximately 3% of women who attend for an early pregnancy scan will find that the fetus has died or has not developed. In this case we can arrange for other procedures that may be necessary

The vast majority of babies are born without any form of disability. However, all women have a small risk of delivering a baby with mental or physical disability and some major abnormalities can be detected at the early pregnancy scan.

Some disabilities such as Down’s Syndrome, can also be caused due to a chromosomal abnormality. The risk of the fetus having a chromosomal abnormality will depend on the age of the mother and the measurement of the amount of fluid found behind the neck of the fetus between 12 and 14 weeks of pregnancy.

Screening Test for you and your baby

Cervical length check

Recent studies have shown that the length of the neck of the womb (cervical length) might indicate the chances for going into labour prematurely. We check this at the time of your 21-22 week scan and discuss the findings with you.

One to two percent of pregnant women have a short cervix measuring lass than 15mm during pregnancy. One out of three women with a short cervix may deliver early (preterm delivery before 34 weeks). There is no known effective treatment to prevent early delivery. We are conducting a national study where women with a shorter cervix are offered pessaries which may contain progesterone. There is no obligation to participate in the study.

If you are found to have a high risk of preterm delivery, we may recommend steroid injections (two injections into your arm or buttock 24 hours apart) when you reach 26 weeks. The injections will help to improve the baby’s lung maturity if preterm delivery happens. If you do not have the injections there is a chance that you may not deliver prematurely and your antenatal care will continue as planned. Some women who deliver earlier than 34 weeks in one pregnancy are more likely to do so in future pregnancies. We will check the cervical length in every subsequent pregnancy and treat you if needed.