An intrauterine device, or IUD, is one of the most popular and effective forms of birth control -- and it's rare to become pregnant while using one. "The IUD has a 99.7 percent efficacy rate," says Lanalee Araba Sam, M.D., an ob-gyn in Ft. Lauderdale. "Very, very few women with one will become pregnant. But I always tell my patients that someone on this planet is that one-in-a-million exception. There are instances where someone becomes pregnant with an IUD in place."
If you're concerned that that could be you, it's completely understandable, since about 25 percent of women stop having their period while on Mirena, a type of IUD that uses the hormone progesterone to prevent pregnancy, says Cristina Perez, M.D., an ob-gyn at the Women's Specialists of Houston at Texas Children's Pavilion for Women. The other type of IUD, ParaGard, uses copper to prevent pregnancy. "ParaGard has no hormones," Dr. Perez explains, so if you're using it, you should still be getting your period as long as you're not pregnant.
Symptoms of an IUD pregnancy
A pregnancy with an IUD in place typically has the same symptoms as any regular pregnancy -- including breast tenderness, nausea, and fatigue -- so if you're experiencing those symptoms and you have missed your period, call your doctor right away to find out if you're pregnant.
It's important to catch such a pregnancy early. An at-home pregnancy test might not indicate a pregnancy as early as a blood test in the office would, so you'll want to be tested by a medical professional.
IUD pregnancy risks
Unfortunately, there are additional risks involved with an IUD pregnancy. "You're 50 percent more likely to miscarry if the IUD is left in place, so the recommendation is to let the pregnancy continue and remove the IUD," says Dr. Sam. But even then, Dr. Sam adds, you're 25 percent more likely to miscarry even if the IUD is removed. So your doctor will want to monitor an IUD pregnancy closely.
There's also a higher risk of ectopic or tubal pregnancy, in which the fertilized egg stays in the fallopian tubes rather than in the uterus. Ectopic pregnancies almost always end in loss of the pregnancy, and need to be treated quickly to prevent permanent damage to the woman's reproductive system.
If you are, in fact, pregnant, your doctor will likely test your blood once, and then again 48 hours later, to make sure the pregnancy hormone, hCG, steadily rises, so he can confirm that your pregnancy is progressing. If it does, it's not an ectopic pregnancy.
Pregnancy after an IUD
Although becoming pregnant with an IUD in place is rare, getting pregnant after having an IUD removed isn't. (That's good news if you want to conceive, and fair warning if you don't!) If you have decided to try to conceive, give your ob-gyn a call to have your IUD removed, and get busy trying. Some doctors recommend waiting three months after removal before you start trying to conceive, to give your body time to get back to its usual menstrual cycle. This helps you to understand when you're ovulating and most fertile. But according to Dr. Perez, there's no medical need to wait: "You can ovulate and get pregnant the next month!"
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