A mother fell pregnant twice in the space of 18 days, both through IVF and natural conception, leaving doctors baffled.
Sandra and David Searle, 36 and 40, began their third cycle of IVF treatment in August 2022 without realizing she was already carrying a child.
This extremely rare phenomenon is known as ‘superfetation’ and Ms Searle is only the tenth recorded case in history: she gave birth to little Michael and Poppy in April.
Superfetation is an ultra-rare phenomenon in which two children are conceived at different times in the same uterus and then born as “twins.”
The Perth couple had undergone IVF twice before giving birth to their children Georgia, five, and Fred, three.
But on the third occasion, perplexed doctors discovered two embryos at different stages of development during the ultrasound.
Poppy and Michael (pictured) are the 10th confirmed case of superfetation in history, where two embryos are conceived separately in the same uterus.
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Health problems had previously ruled out natural insemination and after Ms Searle had what she thought was her period, they began their treatments at the clinic.
“Initially we didn’t understand how this could have happened, especially when you’re going through IVF and it’s all very scientific and fact-based,” Ms Searle said to the West.
Blood tests did not detect Poppy until the insemination process began and when doctors discovered Ms Searle was already carrying twins.
Doctors at the clinic asked the couple if they had sex during the process, as they tried to understand how a double pregnancy could have occurred.
Ms Searle assured them that she and her husband had refrained from trying naturally during their treatment and that this must have happened before.
The natural pregnancy came as a shock to the couple, as Mr Searle had been diagnosed with testicular cancer in 2015.
Around the same time, Ms Searle had also been informed that she had a low egg count.
Under these conditions, doctors warned the couple that their chances of getting pregnant naturally were minimal.
Although the newborns are technically twins, they are born at different stages of development since they spent different lengths of time in the womb.
Poppy weighed three kilos and had developed her sucking reflex when she was born, but Michael only weighed two kilos and didn’t even know how to roll yet.
“He’s probably a month behind developmentally,” Ms. Searle said.
After some minor difficulties during the first week of his life, Ms Searle said Michael was doing very well after five months.
It was the couple’s third successful IVF cycle after Mr Searle was diagnosed with testicular cancer in 2015 and Mrs Searle discovered she had a low egg count.
Mr Searle chose to freeze his sperm before starting chemotherapy so they could still have children later.
“We were very lucky to have one pregnancy in the first place, let alone two, then three, and then to find out that we managed to get a two-for-one deal on the third pregnancy was exciting , but a little scary at the same time”, Mr. Searle said today.
Ms Searle spent a fortnight in hospital before giving birth in the 37th week of her pregnancy.
The couple’s obstetrician was aiming for a 39-week pregnancy, which would have extended Michael 36 and a half weeks in the uterus.
Although only 10 cases of superfetation have been recorded worldwide, it is believed that this phenomenon goes unreported due to its difficulty in detecting.
Dr Richard Murphy, the family’s fertility expert, only discovered the double pregnancy after noticing Ms Searle’s hormone levels were “exorbitantly high” during her first blood test.
A scan showed a fetus 18 days ahead of where it should have been.
“There will probably be other cases that go unreported and we just don’t know,” Dr. Murphy said. told ABC.
“It’s always interesting to document these phenomena because they are so rare that there are a few cases in the literature but not many. So it is interesting for other doctors to see that these rare phenomena can occur.”
WHAT IS SUPERFETATION? THE RARE DISEASE THAT CAUSES A PREGNANT WOMAN TO CONCEIVE TWICE
Superfetation is the rare phenomenon when a woman becomes pregnant with another child while she is already pregnant.
This happens when an egg is fertilized by a sperm and implants a second time in the uterus just days or weeks after the first time in the process.
It is extremely rare, with only a few cases reported in the medical literature – in the UK, Italy and Canada.
Hormonal changes during pregnancy typically block three key processes needed to get pregnant again:
- Ovulation: the body stops releasing eggs from the ovaries during the menstrual cycle
- Fertilization: the body creates a mucus barrier in the cervix that prevents sperm from fertilizing the extra eggs released
- Implantation: The hormones necessary for a fertilized egg to adhere to the uterus are usually not released when a woman is already pregnant.
The low risk of these three processes occurring in a single person means that almost all recorded cases of superfetation involve women undergoing in vitro fertilization (IVF).
During treatment, a fertilized egg is transferred to the woman’s womb. Superfetation may occur if a woman is already pregnant or if she becomes pregnant naturally in the days or weeks following this treatment.
It is difficult to diagnose, because the presence of two fetuses in the uterus is generally assumed to be twins. The main characteristic of superfetation is that the two fetuses grow at different rates.
But there are more common reasons why babies grow at different rates.
Superfetation may increase the younger baby’s risk of complications because they are at higher risk of being born prematurely.
Babies born by superfetation are often born on the same day, they are not officially twins.
Twins are either identical – when a single egg splits into two after being fertilized – or non-identical, when two separate eggs are released and fertilized by different sperm and implanted in the uterus.