Second-trimester minor ultrasound anomalies: impact on the risk of aneuploidy associated with advanced maternal age.

OBJECTIVE

To determine the impact of the presence or absence of minor ultrasound anomalies for the risk of aneuploidy in patients already at high risk because of advanced maternal age.

METHODS

Eleven hundred forty-four women having amniocentesis for advanced maternal age were divided into those with minor ultrasound anomalies (n = 62) and those without (n = 1082). Two hundred fifty-nine women younger than 35 years but with minor anomalies on ultrasound were also included.

RESULTS

Fetal aneuploidy was found in six of 62 (9.7%) women of advanced maternal age with minor ultrasound anomalies, in five of 1082 (0.5%) women older than 35 years with normal ultrasound results, and in five of 259 (1.9%) women younger than 35 years with minor ultrasound anomalies.

CONCLUSION

Minor ultrasound anomalies increase considerably the risk of aneuploidy in women older than 35 years, and their absence lowers that risk slightly. Minor ultrasound anomalies in the fetuses of women younger than 35 raises their risk to that of a 39-year-old women in her second trimester. Ultrasound can be used to modify genetic risks at counseling and may help patients in their decision to have invasive testing.