Third Trimester Fetal Assessment

If the first and second trimesters of pregnancy are defined by embryonic and fetal development, the third trimester is defined by consolidation of these processes through maturation, growth and preparation for delivery. Stillbirth continues to present a major problem in obstetric management and should, by necessity, be a focal point of third-trimester fetal assessment. If congenital abnormalities are excluded, the leading causes of stillbirth are very early preterm birth, intrauterine growth restriction (IUGR), antepartum haemorrhage and infection. A number of tools can be used to assess risks for these complications and their application may help improve fetal outcomes. This chapter describes tools and approaches to third-trimester fetal assessment. Ultrasound is often best applied as one component of multivariate risk assessment and this is the subject of much ongoing research, with applications as diverse as the prevention of stillbirth, shoulder dystocia or maternal perineal trauma.