Pregnancy

Low iron levels can flip the genetic switch on a mouse's sex during development, causing XY embryos to grow female features. But it's not clear whether the effect applies to humans.

Ovarian cysts are fluid-filled sacs that form on or inside the ovaries for a variety of reasons. Often, they disappear on their own, but sometimes, they can grow very large, burst or cause an ovary to twist.

People experience different amounts of pain during IUD insertion, but there are a number of pain-relief options available to patients getting the contraceptive.

The rete ovarii, a poorly understood structure connected to the ovaries, may be much more essential to ovarian function than scientists initially thought.

Performed remotely in Mexico by engineers and embryologists in New York, an automated fertility treatment resulted in conception and, more recently, a live birth.

A man in his early 20s received a transplant of his own sperm-producing stem cells, which had been frozen since his childhood, in an attempt to regain fertility. Doctors are waiting to see if the treatment works.

Oxytocin, a hormone linked to bonding behaviors, might also help mice modulate their pregnancies. Someday, this line of research could improve our understanding of human fertility.

Different versions of a gene called ACE2 affect how well the placenta grows during pregnancy, a laboratory study finds.

A teen girl with abdominal pain learned she was pregnant and had conceived under extremely unusual circumstances.