Superfetation: You Can Get Pregnant While Pregnant

In a shocking twist that contradicts everything we learned in sex education, a recent New York Times Q&A proved that a woman can get pregnant… while she’s already pregnant.

As unlikely as that may appear, the research actually supports it. Under very unusual conditions, a woman can continue to ovulate while pregnant and have another child, a phenomenon known as’superfetation.’

That means a woman can have two foetuses developing inside her at the same time, each at a different stage. And we kind of wish we could erase that knowledge from our minds right now.

Before you get too worked up, this is extremely unlikely to happen to you or anybody you know. In fact, according to a research published in the European Journal of Obstetrics and Gynaecology in 2008, it has only happened ten times in the scientific literature… ever.

Many reports of twin pregnancies have been disproved over the years, but at least ten of them appear to be the real, evidence-backed deal, according to the experts.

There have been a few further examples documented since that publication was published.

In 2009, an Arkansas couple became pregnant after conceiving two and a half weeks earlier. Both kids were delivered safely by c-section on December 2, with one being a fortnight earlier than the other.

In 2015, an Australian couple gave birth to two girls who were born 10 days apart.

So, how does this happen? Superfetation is fairly prevalent in mammals other than humans, and has been observed in rodents, rabbits, horses, sheep, and kangaroos.

These mammals may have two uteri to permit a multiple pregnancy, or their menstrual cycle may simply continue during pregnancy. It’s even thought to be a useful reproductive strategy in some species.

However, superfetation appears to be a very rare accident in humans, because once a woman becomes pregnant, her body actively prevents a second pregnancy from occurring.

“Normally, once a woman is pregnant, the production of eggs ceases, and the hormonal and physical changes of pregnancy work together to prevent future conception,” C. Clairborne Ray noted in a New York Times science Q&A this week.

However, in superfetation, a pregnant woman still manages to ovulate. A male’s sperm then fertilizes that egg, somehow avoiding the mucus plug that closes a woman’s cervix once she’s conceived.

Finally, implantation must take place, which is an extremely delicate procedure even in normal pregnancies. When a woman is already pregnant, her hormones should make the uterus an unfavorable environment for another fertilized egg to implant (not to mention there wouldn’t be much room).

“Three seemingly inconceivable factors appear to need to happen in order for superfetation to occur in humans,” Khalil A. Cassimally reported for Scientific American in 2011.

“Ovulation must occur when a pregnancy is still active, semen must find its way through the blocked cervix to the oviduct, via the occupied uterus, and ultimately, the conceptus must successfully implant itself in an unwary already-occupied uterus.”

Unlike twins, which occur when a fertilized egg divides into two or when two eggs are fertilized by two sperm at the same time, superfetation occurs when a woman becomes pregnant with an additional foetus younger than the existing pregnancy.

So yet, no cases of a significant age difference have been observed.

According to a report published in the European Journal of Obstetrics and Gynaecology in 2008, whenever superfetation was established, the two foetuses had their own amniotic sac. And their sizes varied throughout the pregnancy and after birth.

Given the tiny sample size, scientists are unsure why superfetation happens and whether there are any risk factors that can increase the likelihood of the phenomena.

However, Casimally points out that superfetation reports are more likely among women who have had reproductive treatments, which could explain how one or two of those checkpoints be bypassed.

Despite how uncommon superfetation is, most kids produced as a result of the bizarre event survive.

The major risk is that the infants are still born at the same time, despite their age difference, which means that one of the babies faces the added problem of being born prematurely.

If your head can handle it, you can learn more about superfetation by clicking here and here. The more you learn…