Superfetation, or getting pregnant while you're already pregnant

Recently, some news made the headlines about a surrogate mom who gave birth to twins, but they were actually half-brothers!

31-year-old Jessica Allen, from Perris, California, gave birth to twins around December of last year. Initially, she thought that the twins were the children of a couple in China who enlisted her services as a surrogate mother. However, when she saw that the kids had different skin tones, she realized that one of the kids was actually her and her husband's biological son.

What happened in Jessica's case was that while she was impregnated during the surrogacy process, her egg cell was also fertilized by her husband's sperm, in an extremely rare occurrence called a double pregnancy, or superfetation.

How does superfetation happen?

In humans, superfetation is extremely rare, and in Jessica's case it's very surprising that it happened given that she was already pregnant with a surrogate child.

That's because when a woman gets impregnated, her body stops ovulating, so another egg cell won't be released. But somehow, Jessica's body didn't stop ovulating when the egg was implanted, causing her to become pregnant for the second time.

In some cases, a double pregnancy can be very risky since the babies would grow at different rates. It's not uncommon for babies to be born on separate dates in cases of a double pregnancy. That's because it could happen that a woman is already a few weeks pregnant when another egg can get implanted, which can cause problems since one of the babies would be born prematurely if it isn't detected early on.

How can you tell if you're carrying twins or if you already have a double pregnancy?

The reality is that it's very difficult to distinguish whether or not a mother is carrying twins, or if she has a double pregnancy. Different growth rates aren't sufficient proof of a double pregnancy since it can be the case that twins have different growth rates inside the womb.

The usual way of finding out about a double pregnancy is when an early ultrasound reveals a single fetus, but subsequent ultrasounds suddenly show that the mother actually has 2 fetuses developing inside her. However, this isn't always the case as it can be possible that the second fetus might not be detected early on.

In Jessica's case, however, since the babies have different fathers, a DNA was used to find out if she had twins or a double pregnancy.

Due to the nature of her surrogacy contract, it was difficult for Jessica and her family to gain custody of her son. They had to prove that the child wasn't a twin, and they had to engage in a long and difficult custody battle. In the end, Jessica and her family finally gained custody of her child, and her baby is now living with them in California.

Source: health.com

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