Doctors call it a chemical pregnancy because levels of the hormone human chorionic gonadotropin (hCG) are initially elevated enough to produce a positive result on a pregnancy test but dip again before a doctor can see the gestational sac on an ultrasound.
Many women may not even know that they have experienced a chemical pregnancy if they are not regularly taking pregnancy tests.
In this article, learn more about chemical pregnancies, including the signs and symptoms, causes, and outlook.
Signs and symptoms
A negative pregnancy test after a positive one may be a sign of a chemical pregnancy.
The clearest indication of a chemical pregnancy is a positive pregnancy test result that is followed by a negative one.
These tests can take place either at the doctor's office or at home.
A chemical pregnancy does not always cause symptoms.
If it does, they may include:
- mild spotting a week before an expected period
- abdominal cramping, which is usually mild
- vaginal bleeding that occurs close to the time of an expected period or shortly afterward
Advances in pregnancy tests mean that women can now identify pregnancies as early as the first day of embryo implantation.
However, research shows that up to 25 percent of pregnancies result in miscarriage before a woman has any pregnancy symptoms or misses a period.
The symptoms listed above can also occur with a healthy, ongoing pregnancy. If a woman believes that there are any issues with her early pregnancy, she should talk to a doctor.
A chemical pregnancy does not usually require medical intervention or treatment.
Causes and risk factors
It is not always possible to determine the exact cause of a chemical pregnancy. However, potential causes or contributing factors may include:
- Chromosomal abnormalities: Irregularities in chromosomal arrangements may prevent the fetus from developing. Chromosomal abnormalities are the leading cause of early pregnancy loss.
- Advanced maternal age: Women aged 35 or older may find it more difficult to get and stay pregnant.
- Insufficient hormone levels: The body needs higher levels of certain hormones, such as progesterone, to support the growth of the fetus.
- Low body mass index (BMI): Women who are underweight according to their BMI are more likely to have an early miscarriage.
- Uterine abnormalities: The presence of uterine fibroids or irregularities in the uterine lining can prevent the embryo from implanting in the uterus.
How soon can a woman get pregnant again?
Pregnancy is possible almost immediately after an early pregnancy loss.
Most women can attempt to get pregnant again almost immediately after an early pregnancy loss unless a doctor advises otherwise.
According to the American College of Obstetricians and Gynecologists, it is possible to ovulate and become pregnant again as soon as 2 weeks after an early pregnancy loss.
If a woman has experienced a chemical pregnancy in the past, this does not mean that she will have difficulty conceiving in the future.
In fact, a chemical pregnancy means that an embryo reached the preimplantation phase of development. This is a positive sign that a woman could get pregnant in the future.
According to older research, women who had a chemical pregnancy in their first IVF cycle were more likely to have a successful pregnancy in a subsequent IVF cycle than women who did not become pregnant during the first cycle.
Help after a chemical pregnancy
It is crucial to remember that nobody is to blame for a chemical pregnancy. A person with a history of pregnancy loss can still go on to have a healthy pregnancy and birth.
Chemical pregnancies are those that typically end in the first few weeks after an initially positive pregnancy test. A woman's hCG levels rise enough to produce a positive test initially, but the pregnancy does not continue, and the levels fall soon after.
While a chemical pregnancy can be disappointing, it does indicate that a woman is likely to be able to conceive in subsequent pregnancy attempts.
If a woman has several chemical pregnancies, she should talk to a doctor about potential underlying causes.