Ultrasound screening in the 1st and 2nd trimester

Ultrasonography can be used for the following:

• diagnosis of pregnancy
• abortion
• ectopic pregnancy
• hydatidiform mole
• multiple pregnancy
• dating a pregnancy
• detection of congenital abnormality
• guidance of invasive procedures

Notes (1):

• pregnant women should be offered an early ultrasound scan between 10 weeks 0 days and 13 weeks 6 days to determine gestational age and to detect multiple pregnancies. This will ensure consistency of gestational age assessment and reduce the incidence of induction of labour for prolonged pregnancy
• crown-rump length measurement should be used to determine gestational age. If the crown-rump length is above 84 mm, the gestational age should be estimated using head circumference

Reference:

1. NICE (2008). Antenatal care