Mode
Text Size
Log in / Sign up

Seasons did not significantly affect pregnancy outcomes in infertile patients undergoing IVF-ETDoes the season change your IVF success? For most pregnancy outcomes, the answer is no

AI-generated summary of the cited source, checked by automated accuracy review. How we work

Key Takeaway
Note that seasons did not significantly affect clinical pregnancy or live birth rates in this IVF cohort.

This retrospective cohort study analyzed data from 1,413 infertile patients undergoing in vitro fertilization-embryo transfer (IVF-ET) at a Reproductive Medicine Center. The investigation compared outcomes across four seasons: spring, summer, autumn, and winter. Primary outcomes included the positive rate of human chorionic gonadotropin (HCG), clinical pregnancy rate, miscarriage rate, and live birth rate. Secondary outcomes encompassed embryo quality, blastocyst formation rate, MII oocyte rate, and available embryo rate.

Analysis revealed no significant differences among the four groups regarding general data, embryo quality, and pregnancy outcomes, with a P value greater than 0.05. Specifically, the season did not significantly affect the positive rate of HCG, clinical pregnancy rate, miscarriage rate, or live birth rate. However, the blastocyst formation rate was significantly higher in spring compared to summer. Additionally, the MII oocyte rate was significantly higher in 2019 than in 2020 and 2022, while the available embryo rate was significantly higher in 2019 than in 2022 and 2023.

Safety and tolerability data were not reported in this study. The study did not report specific adverse events, serious adverse events, discontinuations, or overall tolerability profiles. Key limitations include the retrospective design and the lack of reported absolute numbers or confidence intervals for most comparisons, which restricts the precision of the effect estimates. The study phase and publication type were not reported. These findings suggest that while minor variations exist in specific embryological metrics like blastocyst formation, the overall impact of seasons on critical pregnancy outcomes in IVF-ET appears negligible based on this dataset.

If you are trying to conceive with IVF, you might worry that the weather or the season will hurt your chances. This research followed 1,413 patients at a reproductive medicine center to see if the time of year changed their results. They looked at everything from how many embryos formed to whether a pregnancy continued to a live birth.

The main finding is reassuring: the season did not significantly affect your positive pregnancy test, clinical pregnancy rate, miscarriage rate, or live birth rate. In plain terms, getting pregnant in the spring is not better or worse than doing it in the winter for these major outcomes. Even the general quality of the embryos and the data did not differ between the four seasons.

There were a few small differences in specific lab numbers, like the rate of blastocyst formation being slightly higher in spring or the number of mature eggs being higher in 2019. However, these did not translate into better pregnancy results for the patients. No safety issues or side effects were reported during the study. While the study looked at many factors, it is important to remember that this was a review of past records, and the results apply to the specific group studied.

What this means for you:
Seasons do not significantly affect IVF pregnancy success rates for most patients.

Study Details

Study typeCohort
EvidenceLevel 3
PublishedApr 2026
View Original Abstract ↓
ObjectiveWe aimed to investigate the effect of seasons on embryo quality and pregnancy outcomes among infertile patients undergoing in vitro fertilization-embryo transfer (IVF-ET)-assisted pregnancy.MethodsWe retrospectively analyzed data from 1,413 infertile patients who received IVF and antagonist ovulation induction program in the Reproductive Medicine Center of our hospital from January 2019 to December 2023. Based on seasons, they were divided into the spring group, summer group, autumn group, and winter group. The general information, embryo status, and pregnancy outcome of patients in different groups were compared.ResultsThere were no significant differences in general data, embryo quality, and pregnancy outcomes among the four groups (P > 0.05). In multivariate binary logistic regression analysis, season did not significantly affect the positive rate of human chorionic gonadotropin (HCG), clinical pregnancy rate, miscarriage rate, and live birth rate. After adjusting beta regression analysis for confounding factors, the blastocyst formation rate in spring was significantly higher than that in summer, the MII oocyte rate in 2019 was significantly higher than that in 2020 and 2022, and the available embryo rate in 2019 was significantly higher than that in 2022 and 2023 (P 
Free Newsletter

Clinical research that matters. Delivered to your inbox.

Join thousands of clinicians and researchers. No spam, unsubscribe anytime.