This is not what you’d expect when you’re expecting.

One month after delivering her baby boy, a Bangladeshi woman was rushed to the hospital to deliver two more babies: Doctors discovered that she had two wombs, and was simultaneously pregnant in both — the first with her son, then with twins.

Arifa Sultana, 20, gave birth to her first baby in February. Then, 26 days later, she was back in the ER with pain in her stomach. Her doctor told the BBC they were “shocked and surprised” when they did an ultrasound and spotted the twins.

“I have never observed something like this before,” said Dr. Sheila Poddar, the doctor who performed the C-section.

Though rare, Sultana isn’t alone. In 2006, a woman in the UK gave birth to triplets — one baby in one womb and twins in her other womb. The condition of having two wombs, known as uterus didelphys, has resulted in at least 20 pregnancies like Sultana’s, according to a 2017 report on the condition.

Sultana had no idea she was carrying the twins. She told doctors that she and her husband couldn’t afford an ultrasound at the first hospital, which would have revealed the double womb.

Luckily, the twins, a boy and a girl, were healthy and joined their “older” brother four days after the delivery.

“It was a miracle from Allah that all my children are healthy,” the father told the AFP news agency. “I will try my best to keep them happy.”