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.

What are the signs and symptoms of a chemical pregnancy?

Dr. Janet Choi, MD, a board-certified reproductive endocrinologist and chief medical officer for Progyn, explains that a chemical pregnancy often occurs without any warning signs or symptoms. However, some women may experience a delayed onset period, nausea, cramping, bloating, breast fullness or tenderness, and/or spotting.

On the other hand, Dr. Caitlin Dunne, MD, FRCSC, a reproductive endocrinology and infertility specialist at the Pacific Centre for Reproductive Medicine in Vancouver, emphasizes the need for a pregnancy test to confirm a chemical pregnancy. She points out that these symptoms can also occur during a normal period in a non-pregnant person, highlighting the importance of medical confirmation.

How do you test for a chemical pregnancy?

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.

How common is a chemical pregnancy?

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.

Should you see a doctor if you think you’ve had a chemical pregnancy?

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. 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.

Can a chemical pregnancy affect my chances of trying to get pregnant later on?

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 is 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.

Can a chemical pregnancy be prevented?

According to Dr. Dunne, chemical pregnancies are a natural and unavoidable occurrence due to genetic mistakes that are beyond our control. “Most biochemical pregnancy losses (biochemical miscarriages) are due to genetic mistakes in the embryo,” explains Dr. Dunne. “These occur naturally when the egg and the sperm meet and start growing a pregnancy.”

Although there may not be specific measures to prevent chemical pregnancies, Dr. Jenna Turocy, MD, a fertility expert at Columbia University Fertility Center, suggests that there are actions you can take to ensure a healthy pregnancy. “Maintaining overall reproductive health through a healthy lifestyle, managing chronic medical conditions, and avoiding harmful substances can promote a healthy pregnancy.”

What are the treatment options for a chemical pregnancy?

Chemical pregnancies, according to Dr. Turocy, are a natural and unavoidable event that usually requires no specific medical intervention. However, if recurrent chemical pregnancies occur, she explains that a healthcare provider may need to conduct tests to identify potential underlying causes, such as hormonal imbalances, genetic factors, or blood-clotting disorders.

“Once identified, underlying issues such as hormonal imbalances or blood-clotting problems may be addressed through medication or lifestyle changes,” adds Dr. Turocy.

What are the risk factors for experiencing a chemical pregnancy?

Most instances of pregnancy loss are attributed to spontaneous genetic errors in the embryo, with maternal and paternal age being prominent risk factors, as noted by Dr. Choi. She also adds that other risk factors for experiencing a chemical pregnancy include diabetes, polycystic ovary syndrome (PCOS), thyroid disorder, hyperprolactinemia, adenomyosis/endometriosis, as well as antiphospholipid syndrome.

Can hormonal imbalances and blood-clotting problems cause a chemical pregnancy?

Dr. Turocy states that hormonal imbalances and blood-clotting issues can potentially lead to pregnancy complications, including early miscarriages. “Medical conditions like thyroid disorders and PCOS can cause hormonal imbalances that make it harder to get pregnant and increase the risk of miscarriage,” she explains.

“Likewise, antiphospholipid syndrome, a condition that influences blood clotting, can interrupt blood flow to the placenta and potentially increase the likelihood of miscarriage, including chemical pregnancies.”

If you suspect a hormonal imbalance or blood clotting issue may be contributing to recurrent pregnancy loss, it's important to consult with a fertility specialist. “Testing and evaluation can help identify underlying issues, and appropriate management or treatment can be discussed,” adds Dr. Turocy.

Experts:

• Dr. Janet Choi, MD, a board-certified reproductive endocrinologist and chief medical officer for Progyn
• Dr. Caitlin Dunne, MD, FRCSC, a reproductive endocrinology and infertility specialist at the Pacific Centre for Reproductive Medicine in Vancouver
• Dr. Jenna Turocy, MD, a fertility expert at Columbia University Fertility Center
• Beth Taylor, a fertility doctor and co-founder of the Olive Fertility Centre in Vancouver