What is a chemical pregnancy?

After Tanya Courtorielle lost her first baby at 19 weeks, she became what she calls a “pee-on-a-stick addict.” So after more than a year of trying, when she finally got a faint positive result three days before her period was supposed to start, she was thrilled. But at the doctor’s office five days later, she took another pregnancy test, and it was negative.

Courtorielle had experienced what’s known as a chemical pregnancy—a very early miscarriage that shows up on a pregnancy test. “I was disappointed,” she says. “It took 15 months to get that positive, so I was super excited to see it. When the doctor told me it wasn’t a viable pregnancy, I cried.” Her doctor explained that a chemical pregnancy occurs when an egg is fertilized and implants in the uterus, but you miscarry soon after.

Pregnancy tests detect a hormone called human chorionic gonadotropin (hCG) in the urine. hCG rises rapidly during the beginning of pregnancy, doubling about every two days, but in the case of a miscarriage, it drops off over the course of a few weeks. A chemical pregnancy usually shows up in one of two ways: You might see a positive line on a pregnancy test, which will then disappear or become fainter on a subsequent test a few days later. Or you might only ever see a faint line—which is the test picking up the leftover hCG in your body even though you are no longer pregnant.

In women who don’t take a pregnancy test, the only sign of a chemical pregnancy might be a late period. At Courtorielle’s appointment, her doctor told her she could expect bleeding that would be similar to a heavy period.

Chemical pregnancies are very common, accounting for about 20 percent of pregnancies, though it’s not unusual for women to never realize they had one. These early miscarriages are thought to be the result of random DNA abnormalities in the embryo. “The earlier the loss is, the more likely it’s related to the genetics of the egg,” explains Jeff Roberts, a reproductive endocrinologist, infertility specialist and co-director of the Pacific Centre for Reproductive Medicine in Burnaby, BC.

If you think you’ve had a chemical pregnancy, you should visit your doctor to confirm what happened and make sure everything’s OK, especially if you’re having other issues like heavy bleeding. And if you’ve had three or more chemical pregnancies, it might be a sign of fertility issues, so your doctor might order tests to investigate possible problems.

While it can be heartbreaking to lose a pregnancy, try not to panic. “It’s a miscarriage; for most women it’s upsetting,” says Beth Taylor, a fertility doctor and co-founder of the Olive Fertility Centre in Vancouver. “But usually I say, ‘Look, it’s a good sign for a couple of reasons: It means the sperm are good enough to fertilize an egg, at least one of your fallopian tubes is open—it gives us a lot of reassurance about your fertility.’”

And you can start trying again right away. “There’s no reason to wait—in fact, fertility is a little bit higher for the three months following any miscarriage,” says Taylor. It’s not clear exactly why this is, but some think that it might be because your body is primed to support a fetus, through changes like increased blood flow to the uterus. And no matter when you conceive again, for most people, the next pregnancy after a chemical one sticks, and leads to a healthy, full-term baby.

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