Scientists have long noted that there is significant variation caused by seasonal shifts in the number of natural births. The same has been registered in cases of assisted reproductive procedures carried out through the year. Reproductive health of women seems to function along the same biological process that encourages most mammal species to give birth in the spring. Specialists attribute this phenomenon to the hormone melatonin, which influences sleep patterns of organisms, and is believed to make female bodies more fertile during months with longer daylight hours, by acting on reproductive tissues.
This phenomenon was supported by a study presented at the World Congress of Fertility and Sterility. The study observed 1932 patients that underwent IVF through ICSI (intracytoplasmic sperm injection) through the span of a year. It was observed that patients who underwent fertility treatment in the months of March, April and May were 1.5 times more likely to conceive than patients who tried to artificially conceive during any other time of the year.
Dr. Daniela Braga, who led this study at Sao Paolos Assisted Fertilisation Centre, believes that this increase in conception rates is because increased exposure to light triggers the production of estradiol in female bodies, which is a hormone crucial to the fertilisation of the egg and the development of the embryo. This is possibly an effect of changing light on neurons in the brain, which regulate protein hormones in the pituitary gland, which in turn control the secretion of estradiol from the ovaries. It also found that women needed fewer stimulatory drugs to help them ovulate during warmer months. This study is also supported by findings from previous research conducted at the Countess of Chester Hospital and Liverpool Women’s Hospital, which recorded more successful IVF cycles between May and September, than at any given point in the year.
While the findings of these studies have found significant approval and acceptance, there are some that advise against waiting for spring to come around in order to commence the fertility treatment. Dr. David Keefe, Chair of OB/GYN at the Langone Medical Centre in New York City, believes that the point of IVF is to override the natural fertilisation procedures, and this renders the daylights influence on reproductive hormones irrelevant. He also says that human beings have evolved beyond environmental control by virtue of their increasing control on their surroundings in the form of artificial lights, temperature and humidity settings, to the extent that their reproductive systems are now insulated against any environmental changes.
Dr. David Ball, who is the director of a fertility clinic in Minnesota, criticises the perceived phenomenon of increased fertility in the summer, and talks about the perils of this idea gaining popularity, as most women seeking IVF are already short on time to be able to conceive successfully. Prolonging the treatment in anticipation of springtime can have adverse effects on the success rates of the fertility treatment. It is therefore recommended that couples seeking IVF treatment, act sooner rather than later, and not try to manipulate the daylight system.