MONOAMNIOTIC TWINNING AND ZONA MANIPULATION - A SURVEY OF US IVF CENTERS CORRELATING ZONA MANIPULATION PROCEDURES AND HIGH-RISK TWINNING FREQUENCY

Purpose: An anonymous survey of NF centers in the United States was em ployed to calculate frequencies of multiple gestation, monozygotic mul tiple gestation, and monoamniotic multiple gestation. Rates for zona-m anipulated (ICSI, SUZI, zona drilling, mechanical assisted hatching) a nd non-manipulated pregnancies were compared. Results: From 42 IVF cen ters in the United States, a total of 143 pregnancies was ascertained from zona-manipulated cycles. A multiple gestation frequency of 16.1% was reported. Five monoamniotic twin gestations were identified: four from manipulated cycles and one from a non-manipulated cycle. All mono amniotic twin gestations resulted in live births, although three showe d significant intrauterine growth discordance and one newborn was diag nosed with the VATER malformation sequence. Conclusions: Monoamniotic multiple gestations may be increased in zona-manipulated cycles. The p otential obstetric risks and complications of zona manipulation should be discussed with patients.