The main aim of obstetric practice is to ensure that mothers and babies remain healthy during pregnancy and birth. A variety of techniques may be employed to monitor and assess fetal health. This chapter concentrates upon techniques available to assess the health of the fetus. However it should be noted that the mother's health and wellbeing is inextricably linked to that of the fetus and a key element of antenatal care is the careful monitoring and management of the mother's health (see ‘Antenatal care’).

Key issues in assessing fetal wellbeing

The high-risk fetus in the low-risk population

Some mothers are classed as high-risk, i.e. at increased risk of having a baby with a problem due to some known factor, e.g. maternal age and Down's syndrome. Such mothers are relatively easy to identify and offered tests to assess the condition of their fetus (see ‘Screening: antenatal’). However the majority of fetal problems arise in the low-risk population of mothers, who present no obvious signs of having a fetus with an abnormality. A reduction in the incidence of fetal problems rests with advances in identifying the high-risk fetus in the low-risk population (McKenna et al., 2003).

Screening and diagnosis

Diagnostic techniques, whilst providing a definitive answer regarding the presence of a particular problem, can be expensive in time and money and carry a serious risk to the fetus, e.g. amniocentesis, which may result in a miscarriage. These tests are thus unsuitable for widespread use with the low-risk population.