If we thought that (re) getting pregnant when a first pregnancy has already started was scientifically impossible, the phenomenon of superfetation, or superfoetation, completely overturns our received ideas. Around the world, 10 women have fallen pregnant a second time, even though they were already expecting a baby.
Did you think that getting pregnant when you are already pregnant was impossible and worthy of the greatest science fiction films? Well no, it is indeed scientifically possible. A person with a uterus can get pregnant a second time when they already are. An extremely rare phenomenon, it consolidates the idea that we do not yet know everything about the female reproductive system.
While the subject is more than astonishing and raises an infinite questioning, it is very little documented. On the internet, the information is not always very clear. We find a scientific studies on the internet on the subject. In addition, it is impossible to fully understand the superficiality alone in front of his screen. Some health professionals seem to doubt the very existence of superficiality, so this phenomenon is rare and seems absolutely incredible.
However, out of the question to leave you in the dark. We have pooled our knowledge and tried to simplify the data as much as possible to explain this superficial phenomenon to you.
What is superficiality?
Superfetation, or superfoetation, is an incredibly rare phenomenon, since there are only about ten medically documented cases in the world. Yes yes, ten in the world. And for good reason, superficiality is the implantation of a new pregnancy in an already fertilized uterus. In other words, it reveals the extraordinary. In fact, a uterus is not normally endowed with the capacity to receive a second implantation while a pregnancy is in progress. Normally, the decidualization of endometrial cells prevents further implantation. That is to say that once one becomes pregnant, the cells of the endometrium – the uterine lining – are transformed and then allow the exchange of blood and nutrients between the mother and the embryo. Usually, this transformation is only supposed to happen once. It’s scientific. Yet nature got the better of science this time around.
The problem with superficiality is that the two fertilizations are staggered. The two embryos do not have the same term, so one is older than the other.
However, and this is the whole mystery around superficiality, is that it is not essential to have two separate intercourse for another fertilization to occur. In November 2016, Daily Mail shed light on Kate Hill, a young Australian mother of two little girls. While she and her husband were unable to conceive, Kate underwent hormone therapy, and became pregnant. She conceived two babies, but 10 days apart. “I got pregnant and my body spontaneously released another egg, which gave the embryos different gestational ages”, Explains Kate. What is all the more amazing is that she and her husband have only had sex once, which means that the sperm survived for 10 days, when they are only supposed to stay fertile. than 24 to 72 hours after ejaculation.
While Kate was pregnant, her body released a second egg, which is not supposed to happen. Ovulation does not occur in a normal pregnancy. Her first daughter was born on December 20, 2015, and her second ten days later. The girls were not the same weight, height, and blood type. The superficiality, according to the different cases, would often occur after taking ovulation inducing drugs. It has already happened that a woman becomes pregnant naturally – that is to say, having sex – and becomes pregnant again a few days later thanks to medical techniques such as assisted reproduction, because she was unable to not to induce pregnancy.
Another case, this time in America, tells the story of a surrogate mother, who was pregnant with a child of the couple she wanted to help but also with her baby. It is Gentside who shares this incredible tale. It was in the sixth week of pregnancy that the surrogate mother discovered that she was not carrying one, but two fetuses that were not twins!
Are babies born of superficiality twins?
The superficiality is indeed a twin pregnancy, but with different gestational ages and differences in size and weight between the babies.. But are children born of superficiality twins for all that? The opinions are rather contradictory.
On the one hand, some health professionals say no, superficial children are not twins. For the simple reason that although babies are born at the same time, because it is completely impossible to deliver a woman in two stages, they are not at the same stage of development. One of the children is indeed older. In addition, identical twins have the same blood type. Here, this is not necessarily the case. We cannot speak of fraternal twins either, because again, the difference comes from the mismatch in development.
It is also possible that the low number of cases is due to the fact that cases of superficiality have passed for twin pregnancies. Doctor Victor Ddamulira, for Daily Monitor, Explain : “The rarity of this phenomenon can also come from the fact that some cases are not detected, therefore not reported and end up being confused with ordinary twin pregnancies.”. If the second baby was implanted only a few days after the first fertilization, the difference between the two will be minimal, and could then be confused.
On the other side, Doctor Olivier Pirrello, interviewed by Doctissimo, believes that they may be twins. “During in vitro fertilization (IVF), we can make transfers of embryos on D3 and D5, so we can also call it a superification. There can be an embryo like two embryos that implant around D7-D8, so there can be twins. But the term lag is never huge and the pregnancy term is never precise to the day, we will never change it within a week of difference. So this lag goes unnoticed”, He explains. As you can see, the phenomenon of superfoetation is extremely complex and an enigma of biology.
The difference between superfertilization and superficiality
Often confused with superficiality: superfertilization. Although the two phenomena, in their definition, appear to be similar, superfertilization is by no means synonymous with superficiality.
Superfertilization is the fertilization of two eggs by two sperm during the same cycle, but during separate sexual intercourse. What distinguishes it from superficiality is that the latter takes place in two different cycles. This is called a successive fertilization of two eggs during two separate menstrual cycles.
In 2015, Le Figaro reported the story of two American twins, born in 2013 to two different fathers. While the mother requests alimony from her ex-companion for her two daughters, the committee examining her request ask to establish the paternity of the man in order to force him to pay. In her testimony for the New York Times, the mother wanted to clarify having had two sexual relations with two different partners in the same week, during the conception of the little girls. So when the paternity test gives its verdict, it comes as a shock: the father who must pay the alimony is indeed the father, but of only one twin. He must therefore pay the mother money, but only for one of the two sisters, his daughter.
What are the factors that lead to superficiality?
Although the exact causes of superficiality are not really known and very little documented, scientists have speculated about certain risk factors:
- Taking drugs that induce ovulation could increase the risk of superficiality. Several cases, including that of Kate Hill, have occurred after medication.
- Uterine malformation could be at the origin of this phenomenon. This is because the uterus is supposed to accommodate a single fertilized egg within it, but some women seem to prove otherwise.
- During pregnancy, a pregnant woman releases hormones, especially HCGs (gonadotropic chorionic hormone). If the placental production of these HCGs is very high, it can lead to another ovulation.
Obviously, no study is very clear on the subject. The superfluous phenomenon is extremely esoteric and seems to want to remain secret.
Superficiality in animals
While superfoetation is poorly understood and rare in humans, it is much more common in animals, especially in hares and badgers. A female badger or a female hare may well have pregnant fetuses of different ages and different fathers. The interest of these animals is in fact to have as many young as possible per year. While in other mammals a second ovulation during a pregnancy already in place is impossible (at least normally), in badgers and hares, it is quite normal.
In badgers, it is possible that the females favor pregnancies with different dads, in order to avoid the infanticides caused by the males, unable to differentiate their children from others. In hares, the hase (female hare) can be fertilized a second time before having given birth to her young, 3 to 7 days before birth.
Between superfetation, superfoetation and superfecundation, we can get lost a bit. But now, you now know everything there is to know about this more than extraordinary phenomenon. Even though there is little chance that this will happen to you, it is still interesting to know!