HUMAN EMBRYO IMPLANTATION FOLLOWING IN-VITRO FERTILIZATION - IS THEREA SEASONAL-VARIATION

The purpose of this study was to determine whether there is a seasonal variation in implantation and pregnancy rates following natural cycle replacement of cryopreserved embryos. A total of 321 consecutive cycl es were analysed. There were 59 pregnancies (18.4%) and 48 live births or ongoing pregnancies (15.0%), Indicator variables for each month an d variables representing temporal cycles of 12, 6, 4, 3 and 2 months w ere related to outcome, In addition, an analysis of periodicity was pe rformed. No temporal, clinical or demographic variable was significant ly related to pregnancy. This study indicated that there was no clear seasonal variation in the pregnancy rate following natural cycle repla cement, However, the power of this study was low, and it was estimated that 963 subjects would be required to detect a 10% seasonal differen ce in pregnancy rates.