Two ovaries, each connected to the uterus by a fallopian tube. That’s the standard arrangement we were taught in health class. Of course, no one’s body completely matches the textbooks. For various medical reasons, a woman may have an ovary surgically removed.

For a woman with a single ovary, it’s natural to worry about the impact on fertility. Fortunately, in many cases, there is little change in the rate of pregnancy for those who have had an ovary removed. Let’s look at some of the reasons for removing an ovary as well as the key factors affecting fertility with a single ovary.

Reasons for Removing an Ovary

Removing a single ovary is called unilateral oophorectomy, and removing both is called bilateral oophorectomy. Often but not always, the fallopian tube is removed at the same time, and both procedures are most often done alongside a hysterectomy.

Certain health conditions that affect the ovaries or other nearby organs may call for oophorectomy as part of treatment or prevention. In some cases, removing a single ovary is enough, leaving a single functional ovary behind. Conditions that might call for this surgery include:

Some women are born with mutations in the BRCA1 or BRCA2 genes, which normally suppress tumors. Mutations in these genes increase the likelihood of developing breast and ovarian cancers during the woman’s lifetime. To help prevent these cancers, some women elect to have their ovaries removed at or after age 40. This procedure typically calls for removing both ovaries, eliminating the possibility of getting pregnant.

Effects on Fertility

All other things being equal, women with one ovary don’t have a lower chance of getting pregnant compared to women with two ovaries. However, it all depends on why the ovary was removed. An underlying condition like ovarian cysts or endometriosis will affect fertility in its own way.

The most important factor in fertility with a single ovary is whether the ovary is still adjacent to a healthy fallopian tube. Fallopian tubes are not actually attached to the ovaries, but rather hang near them, ready to catch the egg when it is released. If the egg can travel from the ovary, through a tube, and to the uterus, there should be no measurable change in fertility.

While the body normally alternates which ovary releases an egg at ovulation, with one ovary, an egg is still released every month. Even if the ovary is not adjacent to its original fallopian tube, as long as there is a healthy tube on the other side, it is possible for the egg to reach it and then travel to the uterus. However, the chances of a healthy pregnancy drop and the odds of ectopic pregnancy — where a fertilized egg implants outside the uterus — increase.

If you have a single ovary, ask your doctor if your condition may reduce your chances of getting pregnant or put you at risk for complications. If you want more information about improving fertility or tips for conceiving, follow us on Facebook and Twitter, or sign up for our newsletter below.