Read: The high-tech future of the uterus
In most women, this fusion occurs without a hitch. But in somewhere between 0.5 and 4 percent of the population, the walls of the müllerian ducts never really melt away into the surrounding tissue. A failed or incomplete fusion results in one of a few different anomalies. Some can be so minor that they’re never diagnosed: Plenty of women give birth from a uterus that has a small barrier protruding in from the top or a uterus that forks into two. But one of the less common müllerian abnormalities comes up again and again as a viral medical oddity. Women with a condition known as uterine didelphys don’t just have a misshapen uterus: They have two completely separate uteruses, cervixes, and sometimes even two parallel vaginas, with one ovary on each side.
Some cases of didelphys can cause issues such as menstrual blockage during adolescence, but the condition often remains a secret until a woman’s first pregnancy. Sultana reportedly wasn’t told about her didelphys until her second delivery. The doctor who delivered the young mother’s twins told the BBC that she was shocked to see the babies on Sultana’s ultrasound, and chose to deliver them via C-section for safety. In the United States, ob-gyns rely heavily on tools such as ultrasound technology to monitor pregnancies, keeping an eye out for risk factors such as didelphys so that they can plan ahead for any unique challenges expected during pregnancy and delivery. In Bangladesh, rural areas often lack access to diagnostic technologies, and the neonatal mortality rate is more than four times that of the United States. Pregnancy complications that are easily manageable elsewhere can be much more serious there.
Sultana’s story is remarkable because she faced the hazards of her rare condition without serious complication. For one, there’s the risk of miscarriage, says Beth Rackow, an assistant professor of obstetrics and gynecology at Columbia University’s Irving Medical Center. “Each uterus is more like half a uterus, not full-size. So we worry about space constraints, we worry about blood supply, and we worry about the placentas working as well.” Even if a pregnant woman with didelphys is carrying only one child, the resources her body provides to that smaller uterus can fall short of what a growing fetus needs.
Carrying more than one child at a time comes with its own set of risks. Deborah Levine, a radiology professor at Harvard Medical School, says that Sultana is “incredibly lucky” to have given birth to three healthy triplets, with only one preterm birth. Twin pregnancies in didelphic uteruses aren’t unheard of—journals seem to publish one or two case studies a year similar to Sultana’s, often from less developed countries. But safely carrying triplets in two uteruses is that much more unlikely. “Usually, twins deliver early and triplets deliver even earlier,” Levine says, which poses a risk to the infants that hospitals like to be prepared for ahead of time. “Somebody once said that if ultrasounds did nothing besides diagnose twins, it would be worth it, because of the extra care they need.”