A woman getting pregnant while already pregnant is an extremely rare phenomenon called superfetation.
It happens when a second egg is fertilized and implants in the uterus days or weeks after an initial pregnancy has already begun. Normally, pregnancy hormones prevent ovulation, but in superfetation, this suppression fails.
A recent documented case involved a woman who had two embryos of different gestational ages simultaneously—one early intrauterine pregnancy and one ectopic pregnancy in the fallopian tube. She underwent surgery to remove the ectopic pregnancy and later successfully delivered a healthy baby from the ongoing intrauterine pregnancy.
Superfetation can result in twins with different developmental stages or complications like heterotopic pregnancy, where one fetus is inside the uterus and one outside. Diagnosis is challenging because symptoms overlap with typical early pregnancy, but ultrasounds and hormone testing confirm it.
This condition, although exceptionally rare (only about 14 confirmed cases), is becoming more detected with the rise of assisted reproductive technologies. Management depends on the health of the pregnancies and may involve surgery if there is an ectopic pregnancy.
In summary, superfetation is when a woman conceives again during an existing pregnancy, leading to two embryos at different gestational ages. It poses unique diagnostic and management challenges but can result in successful live births.