News | Australian Study: Season and Daylight May Affect IVF Success Rates
An Australian study found that the season and amount of daylight at egg retrieval during assisted reproductive treatment significantly affected IVF live birth rates. The study was conducted by institutions including City Fertility Centre and King Edward Memorial Hospital in Perth, Western Australia, and published in Human Reproduction.
Eggs collected in summer and later used in frozen embryo transfers had a 30% higher live birth rate than eggs collected in autumn. Eggs collected on days with the most daylight also had a 28% higher live birth rate than those collected on days with the least daylight. Temperature did not significantly affect live birth rates, although miscarriage rates were higher when embryos were transferred during hot weather than during cooler weather.
Reproductive endocrinology and infertility specialist Dr. Sebastian Leathersich, who led the study, explained: “Seasonal variation in natural birth rates is well known worldwide, but most previous IVF studies were based on fresh embryo transfers, making it difficult to distinguish environmental effects on egg development, embryo implantation, and early pregnancy. By analyzing frozen embryo transfers, this study identified for the first time the potential effect of environmental conditions at egg retrieval on pregnancy outcomes.”
The data covered 3,657 frozen embryo transfers performed at a Perth fertility clinic from 2013 to 2021. Retrieval dates were divided into three groups by daylight duration: short (0 to 7.6 hours), medium (7.7 to 10.6 hours), and long (10.7 to 13.3 hours). The live birth rate was 30.4% for eggs collected on the longest-daylight days and 25.8% for eggs collected on the shortest-daylight days.
Dr. Leathersich said: “The findings suggest that summer and greater daylight at egg retrieval may be important conditions for higher live birth rates.” Possible explanations include seasonal differences in hormone levels and lifestyle between winter and summer.
Environmental conditions may affect egg quality and pregnancy success
Although factors such as age are critical in fertility treatment, the study suggests that environmental effects on egg quality and embryo development should not be overlooked. Dr. Leathersich noted: “The study clearly suggests that conditions during egg development may matter more than conditions at embryo transfer.” Patients and doctors may therefore consider environmental factors when planning treatment.
Because this was a retrospective analysis, it cannot establish causation and only shows an association between retrieval conditions and live birth rates. The team plans to test the findings in other climates and examine seasonal factors such as air quality to clarify how environmental conditions affect reproductive outcomes.
The researchers also hope to determine whether the findings apply to people freezing eggs for non-medical reasons. These patients can often choose when to undergo treatment. If retrieval in a favorable season is shown to improve outcomes from frozen eggs, it could meaningfully affect reproductive choices.
News | Australian Study: Season and Daylight May Affect IVF Success Rates
News | Australian Study: Season and Daylight May Affect IVF Success Rates
An Australian study found that the season and amount of daylight at egg retrieval during assisted reproductive treatment significantly affected IVF live birth rates. The study was conducted by institutions including City Fertility Centre and King Edward Memorial Hospital in Perth, Western Australia, and published in Human Reproduction.
Eggs collected in summer and later used in frozen embryo transfers had a 30% higher live birth rate than eggs collected in autumn. Eggs collected on days with the most daylight also had a 28% higher live birth rate than those collected on days with the least daylight. Temperature did not significantly affect live birth rates, although miscarriage rates were higher when embryos were transferred during hot weather than during cooler weather.
Reproductive endocrinology and infertility specialist Dr. Sebastian Leathersich, who led the study, explained: “Seasonal variation in natural birth rates is well known worldwide, but most previous IVF studies were based on fresh embryo transfers, making it difficult to distinguish environmental effects on egg development, embryo implantation, and early pregnancy. By analyzing frozen embryo transfers, this study identified for the first time the potential effect of environmental conditions at egg retrieval on pregnancy outcomes.”
The data covered 3,657 frozen embryo transfers performed at a Perth fertility clinic from 2013 to 2021. Retrieval dates were divided into three groups by daylight duration: short (0 to 7.6 hours), medium (7.7 to 10.6 hours), and long (10.7 to 13.3 hours). The live birth rate was 30.4% for eggs collected on the longest-daylight days and 25.8% for eggs collected on the shortest-daylight days.
Dr. Leathersich said: “The findings suggest that summer and greater daylight at egg retrieval may be important conditions for higher live birth rates.” Possible explanations include seasonal differences in hormone levels and lifestyle between winter and summer.
Environmental conditions may affect egg quality and pregnancy success
Although factors such as age are critical in fertility treatment, the study suggests that environmental effects on egg quality and embryo development should not be overlooked. Dr. Leathersich noted: “The study clearly suggests that conditions during egg development may matter more than conditions at embryo transfer.” Patients and doctors may therefore consider environmental factors when planning treatment.
Because this was a retrospective analysis, it cannot establish causation and only shows an association between retrieval conditions and live birth rates. The team plans to test the findings in other climates and examine seasonal factors such as air quality to clarify how environmental conditions affect reproductive outcomes.
The researchers also hope to determine whether the findings apply to people freezing eggs for non-medical reasons. These patients can often choose when to undergo treatment. If retrieval in a favorable season is shown to improve outcomes from frozen eggs, it could meaningfully affect reproductive choices.
Source:
Collected online