The Relationship between Seasonal Variability and Pregnancy Rates in Women Undergoing Assisted Reproductive Technique

Studies in regions with seasonal climatic variations have revealed a correlationbetween human natural conception and birth rates. Holidays and other cultural activities probablyhave influence on conception, but the ambient temperature and emotional influences on the femalehormones related to fertility may play an important part in the seasonal variation in conception.

The aim of study was to determine the relationship between the success rate ofAssisted Reproductive Technique (ART) treatment cycles and temperature in different seasons.

A retrospective study on all individuals undergoing assisted ART at ourinstitution was performed during June 2000 to June 2001. The study population represented 258IVF-ET cycles and 821 ICSI treatment cycles. Different variables were analyzed using χ2 test.

In IVF treatment cycles, conception was more common from early spring (March to June).This decreased from spring, with the minimum in fall, 22% and 14%, respectably. A significantseasonal variability in the number of eggs, embryo transferred and sperm motility was notdemonstrated (p>0.05), but sperm count was significantly higher in spring than any other season(72+4 x106 and 52+7x106, respectively).

The seasonal changes should be taken into account together with other factors whenevaluating infertility data.