Influence of seasonal variation on in vitro fertilization success

Abstract

ObjectiveTo evaluate the influence of seasonal variation on in vitro fertilization (IVF) outcome in a large cohort population.Methods & materialsA total of 5,765 IVF cycles conducted in Sheba medical center between 2013 and 2016 were retrospectively analyzed. The treatment cycles included 4214 ovarian stimulation and ovum pick up (OPU) cycles of which 3020 resulted in fresh embryo transfer and 1551 vitrified- warmed cycles of which1400 resulted in warmed embryo transfer. Cycles were assigned to seasons according to the date of OPU for fresh embryo transfer cycles or according to the date of embryo warming for vitrified warmed embryo transfer cycles.ResultsThere were no statistically significant differences between the calendar months or seasons concerning the number of oocytes retrieved or fertilization rate in the fresh cycles. Throughout the 4 years of the study, the monthly clinical pregnancy rate fluctuated between 18.2% and 27.9% per fresh embryo transfer (mean 23.3%) and between 17.7% and 29.4% per vitrified warmed embryo transfer (mean 23%). These fluctuations did not follow any specific seasonal pattern.ConclusionsOur study did not demonstrate any significant influence of the calendar months or seasons on the clinical pregnancy rates of fresh or vitrified warmed embryo transfers. It might be speculated that the complete pharmaceutical control of the ovarian and endometrial function, as well as the homogeneous treatments, procedures and laboratory equipment used during the study period have lowered the influence of seasonal effect on IVF treatment outcome.

Association between in vitro fertilization success rate and ambient air pollution: a possible explanation of within-year variation of in vitro fertilization success rate

“…Stolwijk et al [22] reported improved pregnancy rates from November to February. Finally, a recent study failed to demonstrate any significant seasonal influence on IVF outcomes [23]. In previous reports, the possible etiology of seasonal variances in IVF success rates was purported to be the length of day, which might suggest the effects of vitamin D exposure and melatonin on the female reproductive tract [24].…”

Seasonal variability does not impact in vitro fertilization success

“…One retrospective study did not demonstrate any significant influence of the calendar months or seasons on the IVF outcome of fresh or frozen embryo transfers. However, the outcome of the study was clinical pregnancy rate and did not adjust for covariates 5 . However, one retrospective observational cohort study indicated seasonality have a significant influence on the fertilization process and on the quality of the human embryos that are obtained in vitro 6 .…”

Seasonal influence on assisted reproductive technology outcomes: A retrospective analysis of 1409 cycles

“…A recent study by Kirshenbaum et al . [ 20 ] from Israel analyzed a cohort of 4420 ART cycles out of which 3020 comprised fresh embryo transfer and 1400 comprised vitrified-warmed embryo transfers. The investigators found no difference in clinical pregnancy rates in consecutive calendar months for a period of 3 years.…”

“…[ 17 18 ] In addition, some investigators further reported no significant difference in fertilization, clinical pregnancy, or LBRs following ART in different seasons. [ 19 20 21 ] The lack of consistency in the results may be attributed to the heterogeneity in study population, ART protocols, ethnicity, and regional variations in types and duration of seasons.…”

“…It is important to note that most of the studies are reported in European[ 17 18 19 ] and Middle eastern[ 15 20 ] population as well as a study from China. [ 21 ] There are no published studies on effects of seasonal variations on ART outcomes from South Asia.…”