Once a month, between two menstrual cycles, the ovary releases the oocyte from the most mature follicle to be fertilized. This is the process of ovulation. In some women, two (or more) oocytes may be expelled during the 24 hours of ovulation, instead of just one. Here is some information you should know about it.
If each oocyte is fertilized by a sperm, fetuses of fake twins, or dizygotic twins, will develop. These twins are born at the same time, but are no more alike than two siblings, because they do not come from the same oocyte. The identical twins, or monozygotic twins, are born from a single egg that has been fertilized by a sperm, but the resulting cell has split into two, thus forming two embryos.
The double ovulation may occur in women taking drugs to promote procreation. These treatments mimic the hormonal fluctuations at the origin of the development of ovarian follicles, and can thus stimulate the expulsion of several oocytes.
These were published in 2003 by the journal Journal of Fertility and Sterility, and led by a Canadian team, which provided a better understanding of the phenomenon of double ovulation. Scientists have understood that the hormonal changes linked to the expulsion of the oocyte can recur at other times of the month, between two menstrual cycles. In that case, follicles grow in waves, without being associated with true ovulation. Double or multiple ovulation will take place within a day, no more. The study made it possible to advance research in the field of fertility disorders.
In the case of natural contraception using techniques such as Billings’, Ogino’s or temperature measurement, the estimation of the ovulation period does not take into account the risk of expulsion of two or more oocytes within 24 hours. The risk of pregnancy is therefore high and the method remains unreliable.