Superfetation: Woman gives birth to twins conceived one week apart

When Cara Winhold walked in for an ultrasound at five weeks pregnant in April 2021, she felt a sense of doom.

“I hated that I felt that way,” Winhold, 31, told TODAY Parents. “I wanted to be optimistic.”

But after experiencing three devastating miscarriages, Winhold, a math teacher in Fort Worth, Texas, was beginning to wonder if having a second child just wasn’t in the cards.

"The losses really took a toll on us," she said.

At the same time, Winhold said she didn’t panic when the sonographer didn’t detect a heartbeat.

“It was still early,” Winhold explained. “I knew I couldn’t lose hope. It's not uncommon to not see a heartbeat at five weeks."

Winhold and her husband, Blake, were told to return in two weeks.

“I was petrified, my blood pressure must have been so high. I remember sitting in the doctor’s office shaking,” Winhold recalled.

Moments later, Winhold was shaking with excitement — and confusion. Not only did the baby have strong fetal heartbeat, but a second fetus had appeared seemingly out of nowhere.

"Everyone in the room was in shock," Winhold said.

It’s a phenomenon called superfetation, and it’s extremely rare. According to Dr. Lisa Thiel, a maternal fetal medicine specialist at Spectrum Health in Michigan, there are only a few confirmed cases.

“Superfetation is when a second pregnancy implants a few days or weeks after an initial pregnancy occurs. A new egg is fertilized by a new sperm,” Thiel told previously TODAY Parents. “The reason this is so rare is because hormones are released by the woman’s body to prevent further ovulation and a thick mucous is created at the cervix to prevent any further sperm from entering the uterus at that time."

Winhold’s OBGYN estimates that the babies were conceived roughly one week apart.

The Winholds welcomed sons Colson and Cayden on October 25, 2021. Colson, the “older” of the two, weighed 6 pounds, five ounces, while Cayden was 4 pounds, 9 ounces. The twins joined big brother, Wyatt, 3.

“It’s dramatic how much bigger Colson is, still. He’s 8 months old but wearing 24-month clothing,” Winhold said. “Cayden is wearing 6-to-9 month sizes.”

Winhold noted that while Colson started sitting up and crawling first, Cayden is more verbal.

But there's a good chance Cayden will catch up with his brother. His mom is 5-foot-11, and his dad is 6-foot-8!

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