Woman conceives second baby while already pregnant

Kathleen Nicole Ramos Santos, 24, conceived her second child one week after her first, leading to both a natural birth and a C-section on the same night to save her babies.

Nicole, a resident of Nova Iguaçu, Rio de Janeiro state, went viral on social media after sharing her unique journey of carrying twins conceived at different times. While the events transpired in 2021, a video detailing this rare medical phenomenon was posted by Nicole on Instagram in late 2025, attracting nearly 700,000 views.

Kathleen Nicole Ramos Santos shared her pregnancy and birth story on Instagram in late 2025. Photo: Instagram

Brazilian media reported that in early 2021, ultrasound scans confirmed Santos was carrying twins. Doctors, however, noted a significant difference in the size and gestational age of the two fetuses. This rare phenomenon, known as superfetation, occurs when a woman ovulates and successfully conceives while already pregnant. For Santos, her second baby was conceived approximately one week after the first.

Santos's pregnancy was categorized as high-risk, necessitating absolute rest. Her two baby girls, Maju and Maya, were born prematurely at 33 weeks gestation during a dramatic delivery.

Santos delivered the first baby naturally and without complications. However, the second baby unexpectedly experienced acute fetal distress, prompting doctors to perform immediate emergency surgery to save the child's life.

"I experienced extreme horror having to deliver my children by two different methods in a single night," the 24-year-old mother recalled, recounting the shock of that year.

The two newborns remained in the intensive care unit for three weeks before their discharge. The postpartum period proved to be a significant challenge for Santos, as she simultaneously cared for her premature twins and her older daughter. After navigating this demanding phase, she decided to share her story, hoping to encourage other mothers facing similar circumstances.

Medical experts state that superfetation is an extremely rare human phenomenon, with fewer than 10 cases documented in global medical literature. Typically, a pregnant woman's body releases hormones that inhibit subsequent ovulation, making additional conception nearly impossible.

Obstetrician-gynecologist Sergio Podgaec affirmed he had never encountered or heard colleagues describe a similar case during his career. Diagnosis primarily relies on ultrasound imaging, which reveals a developmental disparity between the two embryos.

"Although it sounds unbelievable, this is biologically entirely true, and the two twins could even have different fathers," Podgaec explained.