Cara Winhold is a 30-year-old woman from Texas, United States, who after suffering two miscarriages, gave birth to twins with a peculiarity: they were conceived a week apart. That is, she became pregnant while already pregnant, which is known as superfetation.
Cara and her husband Blake are parents of Wyatt, a boy who was born in 2018. But when they decided to expand the family, they lost a pregnancy in 2019 and another in 2020. After the last one, she was very weak, and needed to receive blood transfusions in the hospital.
They had almost given up hope when they found out in March 2021 that she was pregnant again.
When going to the first appointment with the doctor and they performed an ultrasound to confirm the pregnancy, a gestational sac with a baby could be seen.
“When I came back at two weeks – because of my history the doctor wanted to check on me frequently – there was a very small sac in one corner that had another baby . You could see that the first one was more developed and the other one was just a little point,” the mother tells the Daily Mail.
Twins Colson and Cayden entered the world in October 2021, six minutes apart, and a gestational age of 35 weeks. One of them, having been conceived a week later, was born with a development of 34 weeks.
The difference has not been significant in this case, but we have known some cases in which the woman became pregnant when she was three weeks pregnant and the babies were born with a significant size inequality.
Superfetation: getting pregnant while pregnant
Normally, when an egg is fertilized by a sperm and conception occurs, a woman’s reproductive system stops producing eggs.
But very rarely, it can happen that the menstrual cycle repeats itself and a new egg is released while an embryo already exists. Even rarer is that this egg is also fertilized: then superfetation occurs, when two embryos of different gestational ages come together .
These are non-identical or dizygotic twins (known as fraternal twins), since they result from the fertilization of two separate eggs, each with a different sperm, and they develop in the uterus at the same time. They can be of the same or different sexes and are no more alike than any brother or sister, despite being born together.
Superfetation should not be confused with superfertilization, in which two (or more) eggs are fertilized at the same time, which is much more common.
There are very few documented cases of superfetation in the world, around 15, but it is believed that it is a more common phenomenon that is not known.
In this case, Cara became pregnant again during pregnancy and gave birth to siblings born at the same time, what we know as fraternal twins, but having been conceived a week apart .
