Medical Research: What is the background for this study? What are the main findings?
Dr. Vandekerckhove: Several retrospective studies have evaluated seasonal variations in the outcome of IVF treatment. Some also included weather conditions, mostly temperature and hours of daylight. The results were conflicting. We focused on individual variables provided as monthly results by our national meteorological institute. We shifted the results in IVF outcome to the weather results of one month earlier, as we supposed that the selection of good quality oocytes may start in the weeks before.
Between January 2007 and December 2013, the IVF outcome of all Belgian patients treated in our university center was compared to the quarter of the year and monthly mean values of temperature, rain fall, rainy days and sunshine hours during the month when gonadotropins were started or the month before.
11494 patients started an IVF cycle and were included. Firstly bivariate correlation was performed by linear modelling between monthly weather conditions and IVF results. Secondly the same IVF outcome variables were plotted against the weather results stratified per quartile for each individual meteorological variable.
There was no relationship between IVF outcome and the quarter of the year.
When looking for a linear correlation between IVF results and the mean monthly values for the weather, the results were inconsistent.
However, when the same analysis was repeated with the weather results of 1 month earlier, there was a clear trend towards better IVF outcome with higher temperature, less rain and more sunshine hours. The live birth rate per cycle was significantly different (p 0.019) between different groups (Q=quartile) of mean number of sunshine hours (Q1=60.75, Q2=136.00, Q3=174.50).
Medical Research: What should clinicians and patients take away from your report?
Dr. Vandekerckhove: Because of the retrospective design of the study, further adjusting for possible confounding factors such as age of the woman, type of infertility and indication for IVF is mandatory.
The weather conditions seem to have their strongest impact on live birth rates.
Medical Research: What recommendations do you have for future research as a result of this study?
Dr. Vandekerckhove: The impact of sunlight on the early selection of good quality oocytes is an important finding for future research. Maybe we should focus further on environmental factors during the early phases of oocyte recruitment during the period just before ovarian stimulation for IVF. A strong impact of light, as illustrated by the importance of sunny weather, brings melatonin again in the picture for further research and treatment options.
Abstract presented at the annual meeting of the European Society for Reproductive Health (ESHRE) in Lisbon June 2015, discussing the Effects of Sun Exposure on Fertility.
Frank Vandekerckhove, MD, PhD, Clinical Head, Centre for Reproductive Medicine, University Hospital Ghent, & Belgium (2015). More Sunshine Linked to Better IVF Outcomes