What is a chemical pregnancy?

What is a chemical pregnancy?

A chemical pregnancy is a very early pregnancy loss. It happens before the fifth week of pregnancy, usually about a week after a menstrual period is due. Most often a woman's body naturally ends the pregnancy because of a chromosomal abnormality in the developing embryo.

Chemical pregnancies are very common (between 8% and 33% of all pregnancies), though they often happen before a woman even realizes that she's pregnant.

When a chemical pregnancy happens, there's a fertilized egg, but it hasn't completely implanted . It "sticks" just enough for the body to produce the pregnancy hormone hCG .

That can lead to a faintly positive pregnancy test early on. Once the implantation is unsuccessful and the embryo stops developing, however, hCG levels fall and a pregnancy test would show a negative result .

A chemical pregnancy is sometimes called a biochemical pregnancy. These terms refer to the fact that the pregnancy is only detected by hCG (the "chemical") in the blood or urine, not an ultrasound .

Is a chemical pregnancy a miscarriage?

Many women think of a chemical pregnancy as a miscarriage . Medically, however, chemical pregnancy isn't considered a miscarriage because it hasn't yet progressed to the point of being a clinical pregnancy.

A clinical pregnancy means that the gestational sac can be seen on an ultrasound or that the fetal heartbeat can be heard. In a clinical pregnancy, a blood test would show rising hCG levels, while in a chemical pregnancy the hCG levels may be falling, or they may no longer be detectable.

"While it's not technically a miscarriage, a chemical pregnancy can feel as emotionally devastating as one if you've been hoping for a pregnancy," says Layan Alrahmani, M.D., a board-certified ob-gyn, maternal-fetal medicine specialist, and member of the BabyCenter Medical Advisory Board .

Signs and symptoms of a chemical pregnancy

There are usually no signs of a chemical pregnancy (it's too early to have pregnancy symptoms such as fatigue or nausea ), but you might suspect one based on:

• A late period
• A faint positive on an early pregnancy test, followed by a negative test in the following weeks
• Mild cramping or more cramping than usual when you get your period

Causes of a chemical pregnancy

The most common reason for a chemical pregnancy – as well as miscarriages – is a chromosomal abnormality. These abnormalities (which happen when the cells don't divide properly) usually occur randomly, and they don't mean you'll have trouble with a future pregnancy.

Other possible causes of chemical pregnancy include:

• Abnormal hormone levels
• A fetus that begins to implant outside the uterus (an ectopic pregnancy that self- aborts)
• A sexually transmitted infection (STI) such as chlamydia or syphilis
• Uterine abnormalities (difference in the shape or structure of the womb)

Risk factors for chemical pregnancies

Chemical pregnancies aren't predictable, and there usually isn't anything you can do to prevent one. Most women won't have any risk factors, but the following might increase the risk of a chemical pregnancy:

• An untreated blood-clotting disorder
• Uncontrolled diabetes
• Maternal age over 35 (because egg quality decreases with age)
• An untreated thyroid disorder

While statistics seem to indicate that chemical pregnancy rates are higher with IVF conception, that's misleading. Because IVF pregnancies are closely monitored, the chance of diagnosing chemical pregnancies is higher.

If you're having IVF, you can have preimplantation genetic testing to lower the risk of a chemical pregnancy. The testing will identify embryos that don't have chromosomal abnormalities.

Treatment for a chemical pregnancy

Usually no treatment is necessary for a chemical pregnancy. Your body will probably resume your menstrual cycle just as before. Your doctor may want to monitor your hCG levels to make sure you don't have an ectopic pregnancy (when the fertilized egg implants outside the uterus).

You can absolutely get pregnant after a chemical pregnancy, and chances are that your next pregnancy will proceed normally. In fact, it's a good sign that you're able to get pregnant. You won't need any extra tests or procedures because you've had a previous chemical pregnancy.

It's unlikely that you'll have a repeated chemical pregnancy, but if you think you've had more than one, be sure to talk with your doctor or midwife. If you have repeated chemical pregnancies (or miscarriages), your provider may look for underlying causes, such as a thyroid disorder. And they may refer you to a reproductive endocrinologist, who may recommend chromosome tests, hormone tests, blood tests, an ultrasound and/or X-ray of the uterus, and genetic testing. (Many of the tests are the same as those you'd receive to evaluate infertility .)

Coping with a chemical pregnancy

Coping with a chemical pregnancy can be very emotionally painful. While some women never know they were pregnant, others may be very disappointed or even devastated by the loss.

If you're struggling, know that your pregnancy loss is very real, and grief is perfectly normal. Reach out to others who can support you and help you cope. Your doctor or midwife can refer you to a pregnancy loss support group and/or a professional counselor. You might want to talk to others in BabyCenter's grief and loss Community groups. Or you can contact Share , an online community for women dealing with miscarriage.