Superfetation is a rare and quite curious phenomenon, and it happened to a Californian woman, who against all odds and unexpectedly became pregnant while already pregnant.
31-year-old Jessica Allen ended up giving birth to two children of different parents and different genetic and physical characteristics. She was supposed to be carrying only another couple’s baby, for whom she was a surrogate.
Allen told her story to The New York Post in October 2017. It all started when she agreed to ‘rent’ her womb for a Chinese couple.
Allen was already the mother of two children when she accepted the subrogation treatment. The unusual thing was what happened once she was pregnant following the IVF procedure.
The woman became pregnant again, this time from her now husband Wardell Jasper. Read more on our Twitter account @amomama_usa
The pregnancy went smoothly until at six weeks, during a routine ultrasound, Allen's doctors noticed that he actually carried two fetuses.
The doctor told Allen, he said that the possibility of an embryo division is very small, but sometimes it happens.
At that time, everyone assumed that the two babies were identical twins as a result of the splitting of the Chinese couple's embryo. No one considered a much less likely explanation, the so-called superfetation.
While this phenomenon is common in other species, it is certainly strange in humans.
It means that pregnant woman continues to ovulate after conceiving, and therefore is able to conceive a second child, which is developed simultaneously with the first fetus.
The result is usually the conception of twins of different gestational age, and in extremely rare cases, even of different parents.
In the case of Allen and his partner, despite allegedly having used condoms during the pregnancy, they unconsciously managed to conceive a second child.
Allen went on to give birth to what she thought were identical twins through a C-section, and although she never got to hold the children or meet them in the hospital, a photo that she was sent told her that something was happening.
‘I did notice that one was much lighter than the other. You know, obviously, they were not identical twins,’ she told ABC.
Weeks later, while Allen was still recovering from caesarean section, a DNA test confirmed that one of the babies had genetic compatibility with the Chinese couple, but the other child had the genes of Allen and Jasper.
After a legal battle with the agency that organized the subrogation, since it demanded fees to deliver the baby to their genetic parents, Allen and Jasper finally reunited with their son, named Malachi, who was then almost three months old by then.