Some abnormalities can be detected through specific blood tests. This involves taking blood from a vein in the mother’s arm. Blood tests are done routinely and regularly throughout pregnancy. Tests are done to check for rubella, anaemia, and bleeding tendencies. At around 16-18 weeks a test is done to check the level of alphafetoprotein in the mother’s blood, which can help to determine whether the foetus has any serious neurological defects such as spina bifida. The timing of this test is crucial and if dates are inaccurate, the results may be interpreted incorrectly. If the test result is abnormal, and you are sure of your dates, it will probably be repeated, and an amniocentesis will be recommended so that a more certain diagnosis can be made.
An ultrasound scan is routinely performed at around 20-22 weeks to check the progress of the pregnancy, especially the size and maturity of the foetus. It also shows whether there is more than one foetus present. It is your baby’s ‘first photo’ and can be quite an exciting event for the parents. Occasionally the sex of the baby can be detected if the genitalia are clearly seen. You may both decide that you do not wish to know the sex of your baby until it is born. If so, make sure you let the doctor who is performing the ultrasound know, so he can respect your wishes. The test converts sound waves into images on a television screen and is not dangerous. Interpreting ultrasound images requires a lot of experience. Make sure with your GP that the doctor performing the ultrasound is an expert in the field.