Fetal growth delay in threatened abortion: an ultrasound study.

Out of 255 patients with threatened abortion 67 gave a regular menstrual history and at ultrasound examination had a live fetus with a crown-rump length (CRL) of 10-65 mm, equivalent to a gestational age of 7-13 weeks. The CRL of these fetuses was smaller than expected from their menstrual age (P less than 0.01). For this phenomenon we suggest the term early fetal growth delay. Seven patients aborted and one experienced intrauterine fetal death. These eight fetuses had on average smaller CRL than the remainder 59 fetuses (P less than 0.05). Fetal growth delay may therefore be considered a risk factor in threatened abortion.