Chemical Pregnancy

If you have ever felt the joy of a positive pregnancy test, only to be crushed by your period arriving a few days later, you may be among the many women who have experienced a chemical pregnancy. In fact, about 20% of all pregnancies end as chemical pregnancies.

What exactly is a chemical pregnancy?

Chemical pregnancies are miscarriages which occur very early in pregnancy, usually before the 5 week mark, prior to your doctor seeing the gestational sac on an ultrasound. The name “chemical” comes from how these miscarriages are diagnosed: by a “chemical” (e.g., a rise in hCG hormone) instead of an ultrasound.

When you have a chemical pregnancy, the fertilized egg produces enough hCG to cause a positive pregnancy test, but implantation in the uterus is never fully completed. Chemical pregnancies present themselves as an abnormally heavy period or slightly discolored period blood. Since chemical pregnancies are followed by a period, many women fail to recognize them for what they are or think their period was just “late” by a few days. However, with the growing use of early result in-home pregnancy tests, women are now able to detect pregnancies earlier.

The current miscarriage rate in the US is 25%. This means each pregnancy has a 25% chance of ending in miscarraige. However, this rate decreases as time passes and milestones are hit during the pregnancy. For example, once the heartbeat is seen on an ultrasound, risk of miscarraige drops to 5%. Therefore, the sooner a women can detect the pregnancy, the higher the chance of miscarriage.

What causes a chemical pregnancy?

There is still a lot of dispute in the medical world as to why chemical pregnancies happen. Some doctors blame chromosomal abnormalities, advanced maternal age (over 35 years old), clotting disorders, or thyroid issues. But it all boils down to, that either the embryo was not genetically normal or the uterus was not in the ideal condition to support implantation.

A study published in Human Reproduction found that women undergoing IVF had fewer chemical pregnancies than women with unassisted pregnancies. It suggested the ability to choose healthier embryos was linked to fewer chemical pregnancies. However, IVF did not prevent all miscarriages highlighting the importance of the uterine environment in supporting a healthy pregnancy.

But, what makes the uterus ready for conception?

It is the hormone progesterone that is released after ovulation that acts to prepare the uterus to receive the embryo. Medical professionals and various studies have cited that progesterone deficiency or sub-optimal timing of progesterone as one of the most common causes of chemical pregnancies and failed implantation. Therefore, having the right amount of progesterone at the right time will act to most effectively prepare the uterus for implantation.

Several studies in women with recurrent chemical pregnancies, a progesterone supplement given 3 days after ovulation allowed them to carry a pregnancy to full term.

What to do if you have had a chemical pregnancy

First, if you suspect your chemical pregnancy could have been caused by low progesterone, we recommend testing your progesterone levels at home after ovulation with Proov, the next time you ovulate. Proov can help you determine if you have a progesterone deficiency and it can provide you with information to bring to your doctor.

Second, there is no medical reason to stop you from trying to conceive after a chemical pregnancy. It is possible to ovulate and become pregnant as soon as two weeks after a chemical pregnancy. In fact, some studies show trying sooner rather than later may improve your odds at becoming pregnant again. 


Studies have shown that 69% of women who have had a chemical pregnancy and try to get pregnant within three months of their miscarriages were more likely to get pregnant again than those who waited longer--of which only 51% were able to get pregnant. That being said, if you have repeated chemical pregnancies, you should visit your doctor. 


While chemical pregnancies are heartbreaking, knowing more about your body may help you prevent more from occurring and also set you on the path to successfully conceiving.