The Rare Case Of ‘Superfetation’: Californian Woman Became Pregnant While Already Pregnant

Jessica Allen, 31, a resident of California, became pregnant while she was already pregnant. She actually gave birth to “twins” with two distinct set of parents due to surrogacy.

Surrogacy is legal in California unlike in other states in which it is not permitted. Allen met a Chinese couple in a surrogacy agency and agreed to be their gestational surrogate. The doctors conducted a vitro fertilization to create an embryo for the Chinese couple, then implanted it in the uterus of Allen in April 2016, according to LiveScience.

Soon, Allen became pregnant with the Chinese couple’s baby. On the other hand, after six weeks of pregnancy, her doctors have observed that she was carrying two fetuses and not just one. This means that she was carrying two babies.

She was very surprised and thought that the Chinese couple’s embryo split into two resulting in identical twins. On the other hand, her assumption was wrong.

After she had given birth to two babies, the DNA test confirmed that one baby was the Chinese couple’s child and the other baby was Allen’s biological child. And they are not identical rather they look different. What happened to Allen is an extremely rare medical phenomenon called “superfetation.”

Science Alert reports that “superfetation” is an unusual incident in humans in which a pregnant woman continues to ovulate after becoming pregnant resulting into conceiving a second child. This has been reported only 10 or so times in the medical literature. This has become a rarer case of superfetation because the twins have different sets of parents due to surrogacy.


On the other hand, it is more common in the animal kingdom. This phenomenon has been observed in horse, rabbits, kangaroos, sheep, and rodents.

Allen delivered the twin boys through the cesarean section or known as C-section. The first time she saw them, she noticed that one baby was much lighter than the other. She concluded then that they are not identical twins.

After knowing that one child is the Chinese couple’s baby and the other child is hers, she became emotional and started hugging and kissing her son when she was reunited with him. Allen named him Malachi. She said that they weren’t planning to expand their family soon, yet they treasure Malachi with all their hearts.

[Featured Image by GOLFX/Thinkstock]