All pregnant women in Scotland are offered screening. Pregnancy screening aims to enable women and their partners to make an informed choice about continuing the pregnancy, or to accept treatment at an early stage when it is likely to be more effective. A woman's decision to accept or decline the screening tests does not affect the full range of normal antenatal care she is given.
Existing Pregnancy Screening Programmes
Human Immune deficiency Virus (HIV)
HIV can be transmitted from a mother to her baby. The aim of screening is to reduce the number of babies born with HIV.
- Screening for HIV involves taking a blood sample at 10 to 14 weeks gestation which is tested for antibodies to HIV
- Estimated that screening will prevent between one and two mother to child transmissions each year
- Prevalence of HIV among pregnant women increased from 0.02 per cent in 1999 to 0.05 per cent in 2000
In the absence of screening the birth incidence in Scotland would be around 1.5 per 1,000 babies born in Scotland.
- Pregnant women are offered a blood test at 15 to 20 weeks gestation to screen for Down's syndrome
Neural tube defect
- Spina bifida and anencephaly are the two main types of condition together known as neural tube defects. About one in every 500 pregnancies is affected
- To screen for neural tube defect a small blood sample is taken at around 15-20 and the risk identified
- This screening test aims to identify women who are at increased risk of having a baby with neural tube defects and who should be offered (in the context of appropriate counselling) a definitive diagnostic test such as a detailed ultrasound scan
- Pregnant women may have the virus in their blood without knowing it and can pass it on to their babies at birth
- There does not appear to be any increased risk of birth defects in infants of infected mothers but the infants are at high risk of acquiring the infection, becoming chronic carriers and later have a 25 per centchance of dying of liver related diseases
- Screening for hepatitis B is undertaken by testing the blood for the infection at 10 to 14 weeks gestation
- If the mother is a carrier then the baby can be protected through a vaccine programme from birth. Without treatment up to 90 per cent of infected newborns can develop chronic hepatitis B
- 40 to 70 per cent of pregnant woman with untreated, active syphilis will pass the infection to their unborn child
- Screening for syphilis is undertaken by testing the blood for the infection at 10 to 14 weeks gestation
- Effective treatment (a course of antibiotics) can prevent the infection affecting the baby