Having a child after 40 carries risks, there is no doubt about it. But the number of birth defects and diseases is said to be lower in women who have had in vitro fertilization (IVF) than in those who conceived naturally. It’s a study published by the journal International journal of obstetrics & gynecology (BJOG) which indicates it.
This is because medically assisted reproduction, like IVF, tends to increase the risks for the unborn child. But the “quite remarkable reverse phenomenon”, unexplained by researchers, occurs in mothers 40 years and older who have used this method. Scientists at the University of Adelaide, Australia, analyzed data from 300,000 natural births, 2,200 births from IVF and 1,400 births from intracytoplasmic sperm injection (ICSI), a very used in cases of infertility which consists of injecting a sperm into a mature oocyte, between 1986 and 2002.
The role of ovarian stimulation
Overall, when the mother’s age is not taken into account, the average frequency of congenital anomalies or diseases is 5.7% for babies conceived naturally, 7.1% for those born from IVF and 9.9% for those from ICSI. But, surprisingly, while the risks in babies born by IVF or ICSI are 9.4% in women under 30, they drop to 3.6% in women over 40.
However, in the event of natural conception, the figure is 5.6% for young women and 8.2% for women over 40. The risks of abnormalities are therefore less frequent when the expectant mother over the age of 40 has had IVF rather than natural conception. The researchers hypothesized that ovarian stimulation, mandatory in the event of medical fertilization, would be capable reverse the age-related decline in ovulation.