The cases are extreme rare, ten at most identified in the world. The phenomenon of superficiality is a subject still difficult to tackle because of its complexity. This natural phenomenon translates into fertilization as the implantation of a new pregnancy into a uterus that already contains a developing pregnancy.
Normally, when a woman is pregnant, the ovaries stop sending eggs to the uterus after the hormonal system has informed her of the preparation for the pregnancy. But in the context of a superfetation, the body can release another egg.
Indeed, superficiality is a phenomenon resulting in the conception of a new embryo only a few days after a first conception, even if the release of eggs should normally stop once the pregnant woman. This phenomenon is actually much more common in mammals other than humans such as rodents, rabbits, horses, sheep or kangaroos. Sometimes these animals have two uterines to facilitate double pregnancy or their continuous menstrual cycle simply during pregnancy. But in humans, superficiality seems to be more of a very rare accident.
In which case do we deal with a superfluity?
Philippe Deruelle, gynecologist-obstetrician and secretary general of the National College of Gynecologists and Obstetricians French, argues that the phenomenon of superfluity involves the conjunction of a number of factors. It takes two fertilizing relationships and one oocyte (ovum) that lasts, because the life of an oocyte is 3 to 5 days and highlights two hypotheses. Either, the two ovulations are shifted in time, which is on the hormonal level, complicated, or both reports have generated two fertilizations.
It also states that this phenomenon has no impact on the health of the fetus and that both pregnancies will have normal surveillance, as for twins. "There would be no negative effect for babies, other than the usual risks associated with the birth of twins," he said.
The Independent, Dr. Suvir Venkataraman of the Harley Street Fertility Clinic.
Around 10 cases worldwide
One of the ten cases in the world is Kate Hill, an Australian woman who has twice been pregnant with two girls born on the same day. In 2006, the young woman learned that she was suffering from
Stein-Leventhal, more commonly known as "polycystic ovaries", a disorder causing hormonal imbalance and disrupting ovulation. After undergoing treatment, she became pregnant the first time and ten days later she learned that she was expecting a second child, miraculously.
Dr. Brad Armstrong, an obstetrician at the Brisbane Hospital, Australia, told Today Tonight magazine that there are so few tangible sources of information about the superficial phenomenon in the scientific literature that it has been forced to use the Google search engine to collect information on this extremely rare phenomenon. A publication on the Daily Mail also explained the rarity of this syndrome.
Not being conceived at the same time, the two little girls of Kate Hill, still in the belly of their mother, had a different date of term and to avoid any risk of complication, it had been programmed delivery by caesarean for the Australia. Charlotte and Olivia are finally born before the date of the term, in good health. According to medical reports, each had a different weight, size, blood group, and gestational development.
Why such cases occur?
For such a phenomenon to occur in humans, it would appear that biologically impossible factors must occur, according to Khalil A. Cassimally. He tells Scientific American that for ovulation to be possible during an ongoing pregnancy, the sperm must somehow find its way through the blocked neck to the oviduct (the conduit through which the egg leaves the ovary) and finally implant successfully in an already occupied uterus.
Given the small number of reported and scientifically verified cases, it is unclear to date why superfluity occurs and whether there are factors that can increase the likelihood that the phenomenon will occur.
