Trisomy 22: a cause of isolated fetal growth restriction.

The management of severe isolated fetal growth restriction at term involves consideration of the risk of associated aneuploidy. A case is described in which intrauterine growth restriction was detected at 37 weeks' gestation in a structurally normal fetus. The diagnosis of trisomy 22 was made after fetal blood sampling. This diagnosis has not been previously reported in a structurally normal fetus. This case highlights the dilemma that arises in the management of the small, structurally normal fetus in the late third trimester. The reasons for survival to term of some trisomy 22 fetuses are as yet unclear and are discussed.