SEX-RATIO IN TRIPLETS

Since the introduction of different ovulation induction regimens the i ncidence of triplet pregnancies increased from a spontaneous rate of a bout 1:10 000 to the frequency of nearly 1:1000. Sex ratio of trigemin i and male/female proportion of the three newborns within the same tri plet set is the amazing issue that we at tempted to elucidate in the p resent study. Data on 36 women with triplet pregnancies delivered in o ur hospital and information regarding 2717 tripler pregnancies reporte d by 16 relevant papers were included in this study. 36 women delivere d 63 (58%) male and 45 (42%) female babies. Triplet sets of same gende r comprised 33% of all trigemini. Sex ratios (male/female) for the spo ntaneous, menotropin and clomiphene group were 2.00, 1.57 and 0.94 res pectively. Homogenous male/female set ratio was 5.0, 2.0 and 0.5 in me notropin, spontaneous and clomiphene groups respectively. As the perce ntage of ovulation induction triplet pregnancies increased constantly from 0% to 100%, a decline in the fraction of homogenous gender triple t sets was observed - from 73% to 23%. It may be concluded that sex ra tio in triplet newborns is divergent according to different publicatio ns with most of the authors reporting a male/female ratio of less than 1.00. Ovulation induction results in a lower proportion of homogenous sex triplets sets. Superovulation by menotropins cause a higher perce ntage of male triplet newborns when compared to ovulation induction by clomiphene.