Effect Of Temperature Fluctuation On Clinical Pregnancy Rate Of In Vitro Fertilization And Embryo Transfer

Objective:To investigate whether temperature fluctuations affect the clinical pregnancy rate of in vitro fertilization and embryo transfer(IVF-ET).Methods:We collected the medical records of Gn RH-antagonist protocol and fresh embryo transfer cycles in the Department of Reproductive Genetics Center,the first affiliated hospital of Shanxi Medical University from January 2018 to July 2020 retrospectively,and there were 294 examples met eligibility and exclusion criteria.Then we recorded the date of ovum pick-up,fresh embryo transfer and 7th day after ovum pick-up,and clinical pregnancy outcome of every cycles.At the same time,we collected the historical temperature data during this period and calculated the degree of diurnal temperature range(DTR)and Temperature Variability(TV)of every cycles’ date of ovum pick-up,fresh embryo transfer and 7th day after ovum pick-up.DTR or TV≥P75 were considered as large temperature fluctuations,and ≥P95 were extreme temperature fluctuations.Next,we put all the data into 6 groups on the basis of phases of cycles and evaluation indexes of temperature: ovum pick-up day-DTR group,ovum pick-up day-TV group,embryo transfer day-DTR group,embryo transfer day-TV group,7th day after ovum pick-up day-DTR group and 7th day after ovum pick-up day-TV group,then we put those groups respectively into <P75 subgroup,≥P75 subgroup and <P95 subgroup,≥P95 subgroup,and the total number of cycles,the number of clinical pregnancies and the number of not clinical pregnancies in each subgroups were recorded.Finally,we compared each groups’ clinical pregnancy rate between<P75 subgroup and≥P75 subgroup,between<P95subgroup and ≥P95 subgroup.If there was any statistical difference,relative risk analysis would be conducted on the data of this group to evaluate the direction and extent of the influence of temperature fluctuation on clinical pregnancy rate.Results:In ovum pick-up day-DTR group,7th day after ovum pick-up day-DTR group and 7th day after ovum pick-up day-TV group,the clinical pregnancy rate of ≥P75 subgroup were significantly lower than <P75 subgroup,and the difference was statistically significant(P<0.05);except that the clinical pregnancy rate of ovum pick-up day-TV ≥P95subgroup had an upward trend compared with < P95 subgroup,the whole rest groups’ clinical pregnancy rate of ≥P75 subgroups had a downward trend compared with< P75 subgroups,and <P95 subgroups and ≥P95 subgroups were the same,but the difference was not statistically significant(P > 0.05).Relative risk analysis was conducted among the three groups with differences,and the results indicated that the clinical pregnancy rates of ovum pick-up day-DTR ≥P75 subgroup,7th day after ovum pick-up day-DTR≥P75subgroup and 7th day after ovum pick-up day-TV ≥P75 subgroup were all reduced,with statistical significance(RR<1 and 95%CI excluding 1).Conclusion:Temperature fluctuations may reduce clinical pregnancy rates of fresh embryo transfer cycle of Gn RH-antagonist protocol.