Superfetation: when the mother contains two fetuses of different ages

A husband and wife from Arkansas, United States, experienced what was initially thought impossible but turned out to also happen. The wife was carrying a two and a half week old fetus when doctors realized that in her womb there was another fetus that had just formed. Yes, this woman actually contains two fetuses of different ages!

This very rare phenomenon seems to have been recorded in history in 2015. A couple from Australia was carrying a ten-day-old fetus when doctors discovered another new fetus. Being pregnant with two fetuses of different ages is known as superfetation.

What is superfetation?

Superfetation is a rare occurrence in which a fetus forms in the uterus of a woman who is carrying another fetus from earlier conception. So, she will contain two fetuses of different ages.

However, the two fetuses were not twins. In the case of multiple pregnancies, the fertilized egg cell divides and becomes two separate fetuses. Or two different eggs will be fertilized by two sperm cells at the same time. The ages of the twins are definitely the same because they come from the same menstrual cycle.

Whereas in the case of superfetation, the two fetuses came from different eggs and fertilization. The ages of the two fetuses are of course different. Usually the age of the fetus is several days or several weeks apart.

Superfetation cases are quite common in other species such as rats, rabbits, horses and sheep. However, there are less than ten cases of superfetation that have been recorded and have been medically proven. Superfetation was first noticed in 1960.

How did superfetation come about?

Pregnancy with a fetus that is different in age was considered impossible. After fertilization occurs, the hormones in the body are supposed to stop the ovulation process. As a result, eggs will not be produced for the next nine months.

Meanwhile, superfetation occurs when a woman who is pregnant ovulates. When you ovulate, the egg is released by the ovaries. If during this time of release, the egg meets the sperm cell, the next fertilization will occur.

Until now, there has been no research or theory that has succeeded in answering how a woman can ovulate when she is pregnant. According to the obstetrician who was interviewed by the WebMD health site, dr. Jeffrey Kuller, this superfetation phenomenon will be very rare in humans. It is not certain that this incident can happen again. Scientists will continue to try to solve the mystery behind this rare phenomenon.

What will happen to the two fetuses with different ages?

Both fetuses will grow in the mother's womb like twins. However, because the ages are different, the development is certainly not the same. The birth date is also different, depending on the age of each fetus.

However, of all the cases that have been recorded, a fetus of different ages will eventually be born at the same time. This is not a problem because usually the baby's age difference is only a few weeks apart. So, the second baby can be born safely and healthily.