MANAGEMENT OF TWIN PREGNANCIES DISCORDANT FOR ANENCEPHALY

Objective To examine options of management and outcome of twin pregnan cies discordant for anencephaly. Design Retrospective study. Setting R esearch Centre for Fetal Medicine. Population Twenty-four twin pregnan cies discordant for anencephaly. Methods A computer search was made of our database for twin pregnancies discordant for anencephaly. The dat a were reviewed for gestation at presentation, chorionicity, managemen t and pregnancy outcome. Main outcome measures Pregnancy outcome in re lation to chorionicity and management. Results There were 13 dichorion ic and 11 monochorionic twin pregnancies discordant for anencephaly. I n the dichorionic group five pregnancies had selective fetocide at 17 to 21 weeks; one pregnancy resulted in spontaneous abortion but in the others a healthy infant was born at a median gestation of 37 weeks. T he other eight dichorionic pregnancies were managed expectantly, but t hree developed polyhydramios at 26 to 30 weeks; in one case amniodrain age was performed and in another selective fetocide was carried out. I n this group the median gestation at delivery was 35 weeks. All 11 mon ochorionic pregnancies were managed expectantly and in three there was intrauterine death of both fetuses. In the other eight cases the norm al twin was liveborn at a median gestation of 34 weeks; in four of the se pregnancies polyhydramnios developed and two were managed by amniod rainage. Conclusions In monochorionic pregnancies, expectant managemen t is associated with a high rate of intrauterine lethality of the norm al twin. In dichorionic pregnancies selective fetocide in the second t rimester prevents the development of polyhydramnios and is associated with a lower risk of preterm delivery but can cause miscarriage.