So…you can get pregnant while you’re pregnant

John Hopton for redOrbit.com – @Johnfinitum
Can you really get pregnant while already pregnant? It could fall into the same category of crazy advice column questions like “can you get pregnant from a sneeze?” Except for the fact that it is an entirely real possibility.
(We wondered if this was like an Inception baby, where there’s a baby inside a baby inside a baby. Alas, it is not, but please read on.)
It is a rare possibility, of course. According to Time, as of 2009 there were only 10 recorded cases of the phenomenon, known as superfetation.
Gutenberg.org defines superfetation as: “the simultaneous occurrence of more than one stage of developing offspring in the same animal,” and gives the following examples:
In 1992, Evan and Taylor Barth, conceived 4 weeks apart, were born in Hawaii to Michelle and John Barth. Taylor, the one conceived later was born first. Evan, conceived first, was born twenty-two minutes later.
In 1960, John and Mary Tress of Baltimore MD had what the nurse called twins. She was wrong. Dr. Paul C Weinberg of Mt. Sinai hospital delivered the boys, Anthony John and Mark Francis, and realized that Anthony, born five minutes before his brother Mark, looked premature. Immediately Dr. Weinberg did x-rays of the boys’ thigh bones and noticed a disparity in bone age. Mark was a full-term baby born five minutes after his two months premature brother Anthony. Anthony was conceived a full two months after his brother Mark.
There have been much more recent cases, too.
In 2007 Ame and Lia Herrity, conceived 3 weeks apart, were born in the UK to Amelia Spence and George Herrity, and in the same year Harriet and Thomas Mullineux, also conceived 3 weeks apart, were born in the UK to Charlotte and Matt Mullineux.
Disproving “common knowledge”
The most recent and most widely publicized case is that of Julia Grovenburg, who became pregnant with two babies who were not twins and were conceived around two and a half weeks apart. International media reported on the case in 2009.
ABC News was one of the first to cover the story. They said at the time of the discovery via ultrasound that:
“Doctors successfully located Todd and Julia Grovenburg’s growing baby girl Jillian, but then discovered another smaller baby – what could be Jillian’s younger brother – growing beside her.”
“The Grovenburgs may have conceived their son Hudson a full two-and-a-half weeks after Jillian, according to statements given to KFSM-TV in Ft. Smith-Fayetteville, Ark. Different from identical twins or fraternal twins, the Grovenburg babies would have separate due dates and are considered to be a rare medical occurrence.”
Dr. Karen Boyle of the Greater Baltimore Medical Center, told ABC News: “When the woman had her ultrasound initially, they saw one sack, one baby developing, and that baby had a certain gestational age; then they noticed a second heartbeat in a child that was much, much younger developmentally.”
In 2011, Julia Grovenburg told the Daily Mail: “It’s common knowledge and written down in medical books that you can’t get pregnant while you’re already pregnant, but somehow after years of trying to conceive I was the exception to the rule. I got pregnant twice in two weeks.”
By then, she had been confirmed as the 11th recorded case in history to have experienced superfetation.
The 11^th case in human history, that is. Superfetation is more common among some animals, including rabbits, rodents, farm animals (horses and sheep), and kangaroos.
Superfetation can sometimes cause problems for one of the siblings, but happily Julia Grovenburg successfully gave birth to both babies – on the same day.
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