Prenatal diagnosis and management of sex chromosome aneuploidy: a report on 98 cases.

OBJECTIVES

To analyse the management of pregnancy after prenatal diagnosis of sex chromosome aneuploidy (SCA) and the factors influencing genetic counselling and parental decision.

METHODS

Between 1991 and 2001, 73 non-mosaic fetal SCA were diagnosed in our centre and 25 were referred to us from outside institutions. The same geneticist carried out genetic counselling. The outcome of pregnancies and the termination trend over time were determined according to the type of SCA. Clinical parental data were analysed in order to assess whether they influenced genetic counselling.

RESULTS

45,X was diagnosed in 41 fetuses. The main indication for karyotyping was abnormal ultrasound (83%). The termination rate was 93%. Sex chromosome polysomies (SCP) including 47,XXY, 47,XXX, and 47,XYY were diagnosed in 31, 16, and 10 fetuses respectively. The main indication for karyotyping was advanced maternal age (60%). The termination rate was 32, 25, and 20% respectively. The difference between the termination rate for local cases (25%) and referred cases (33%) was not significant. The termination rate for pregnancies with SCP was 38% in 1991 to 1994, 34% in 1995 to 1998, and 12% in 1999 to 2001. The parents' characteristics did not influence the outcome of pregnancy.

CONCLUSIONS

The relatively low termination rate (28%) in pregnancies where the fetus was affected by SCP and the decreasing termination trend over time in our centre suggest an improved knowledge of the pathological conditions associated with SCP, influencing genetic counselling.