Find out if you need to worry about pregnancy after your procedure, too

The wife of NFL player Antonio Cromartie announced on her Instagram page that she’s pregnant with their sixth child—and his 14th overall, according to TMZ.

The surprising part? This is the second time his wife has gotten pregnant after his vasectomy.

A vasectomy is a surgical procedure where your vas deferens, or the duct that carries sperm from your testicles to your urethra, is cut or severed to seal it off. It’s considered a permanent form of birth control. So how the heck can you get a woman pregnant not once, but twice after undergoing it?

CAN YOU GET HER PREGNANT AFTER A VASECTOMY?
While it is rare, pregnancy after a vasectomy is actually not unheard of, says Men’s Health urology advisor Larry Lipshultz, M.D., who didn’t treat Cromartie so can’t speak specifically about his case. In fact, the risk of pregnancy after vasectomy is roughly 1 in 2,000 for men whose vasectomies showed no sperm or only rare non-motile sperm (RNMS) afterwards, according to the American Urological Association.

That analysis is a vital part of post-vasectomy care to show that it worked. Usually, men return to the clinic for a follow-up about three months after their vasectomy, so their doctors can examine a semen sample to make sure it’s clear of baby-makers, says Dr. Lipshultz. In fact, you’re told to use a backup form of contraception until an analysis can confirm that your vasectomy was successful.

In some offices, doctors use a single drop of semen and examine it under a microscope to see if there are any swimmers. (Dr. Lipshultz uses a more comprehensive procedure that concentrates a sample.) But there are no required standards when it comes to that test.

CAN YOUR FERTILITY COME BACK AFTER A SUCCESSFUL VASECTOMY?
But even if you’ve received a clean report of zero sperm, that doesn’t mean that your fertility can’t pop back up down the line. Some weird stuff can occur afterwards that can lead to pregnancy, Dr. Lipshultz says.

Take something called “spontaneous recanalisation.” That’s when your vas deferens manages to “grow back,” once again giving your sperm access to the tube that carries it outside your body. This can make the you fertile again, even if it’s only for a brief time.

There’s also chance of a “sperm granuloma,” in which sperm form a lump at the site where your vas deferens is tied off. Dr. Lipshultz says that this can cause a momentary re-establishment of fertility, before the sperm count goes back to zero.

Both of these conditions are considered very rare, though.

WHAT IF YOU DON’T FOLLOW UP WITH YOUR DOCTOR AFTER A VASECTOMY?
Of course, it’s also possible that Cromartie didn’t have a post-vasectomy semen analysis at all. And he wouldn’t be alone in skipping it. One study found that only 25 percent of men returned for their three-month check. That’s a problem, since if you don’t know for sure whether you’re sperm-free, you may be having unprotected sex thinking you’re in the clear—which raises your risk of unplanned pregnancy if you still have some sperm hanging around.

The biggest question for Dr. Lipshultz is why Cromartie didn’t get a semen analysis after his wife got pregnant the first time post-vasectomy. (According to TMZ, his wife gave birth to twins in May of 2016 after his vasectomy.)

“The takeaway here is to make sure to get a semen analysis after your vasectomy,” says Dr. Lipshultz. “Don’t just assume that because you had the procedure that your sperm aren’t still active. Get it checked.”

Originally published on menshealth.com