What is a Chemical Pregnancy & Why Does It Happen?
Medically reviewed by Rachel Liberto, RN on August 26, 2019
- A chemical pregnancy is a miscarriage that occurs before the fifth week of gestation
- Most chemical pregnancies are a result of chromosomal abnormalities
A chemical pregnancy is a miscarriage that happens that occurs before the fifth week of gestation, or within about one week of when you would have expected your period.
Is a chemical pregnancy a miscarriage?
A chemical pregnancy is definitely still a miscarriage—it’s just the name used to describe a very early miscarriage.
Why do chemical pregnancies happen?
Miscarriages, even when they happen very early, can feel like monumental losses. It’s normal to get attached to a vision of the future as soon as you see that positive pregnancy test. But in the case of chemical pregnancies, the embryo was likely predestined to miscarry even before the first cell division.
Typically we think of pregnancy as beginning from the moment of conception—when the sperm enters the egg and fertilizes it. But recent research suggests that conception is not actually a rare event, and that when sperm are present at the time when ovulation occurs, most eggs will be fertilized. However, only about one third of these fertilized eggs will be fit enough to complete implantation.
If the embryo does not manage to successfully implant, you would never know that conception had occurred. Chemical pregnancies are, in many ways, a cruel trick of nature, because they are strong enough to make it to implantation and turn a pregnancy test positive, but not strong enough to progress beyond that point.
Will my period be heavier after a chemical pregnancy?
With most chemical pregnancies, your period should be approximately normal because there is about the same amount of uterine tissue built up to shed as with a normal period.
How do you know if you had a chemical pregnancy?
The only way to know if you had a chemical pregnancy is if you get a positive pregnancy test. Since chemical pregnancies do not usually affect the heaviness or consistency of menstruation, having an unusual period cannot be considered a sign of a chemical pregnancy in absence of a positive pregnancy test.
Due to the advent of highly sensitive home pregnancy tests, more chemical pregnancies are detected today than they were in the past.
Is it implantation bleeding or a chemical pregnancy?
Implantation bleeding isn’t a medical term, and studies have not found any evidence that the process of implantation causes bleeding.
Bleeding is common in early pregnancy, however (though it usually does not occur on the day of implantation). About 20 percent of women experience spotting during the first trimester, and the majority of them go on to have full-term pregnancies. Spotting or bleeding following a positive pregnancy test does not necessarily mean that you are having a miscarriage.
Do you need to see a doctor after a chemical pregnancy?
Very early pregnancy losses do not usually require medical intervention, but if you experience sharp or stabbing pain, unusual vaginal bleeding, weakness, dizziness, or fainting, you should see your medical provider to rule out ectopic pregnancy.
Usually, having one or two chemical pregnancies is not a sign of any underlying problem. If you have three chemical pregnancies in a row, your healthcare provider may want to do testing to rule out medical problems that may be causing them. If a health condition is contributing to your early pregnancy losses, treatment should help you conceive a healthy baby.
What causes chemical pregnancies?
While it’s usually not possible to determine the reason for an individual chemical pregnancy, most miscarriages—including chemical pregnancies—are a result of chromosomal abnormalities.
After egg and sperm combine chromosomes, the resulting zygote grows through rapid cell division. This is the time when chromosomal abnormalities have the potential to occur. These abnormalities are random and can happen to anyone. In most cases, nothing you did caused—or could have prevented—the miscarriage.
If you had a chemical pregnancy, chances are very high that you will be able to conceive a healthy pregnancy in the future. But several factors do increase the risk for chemical pregnancies, including advanced maternal age (over 35), clotting disorders, and thyroid conditions.
What will I experience if I have a chemical pregnancy?
The typical chemical pregnancy experience goes something like this: you get a faint positive pregnancy test around the time your period is due. If you take another test the next day, you may notice that the second line is lighter or no longer there. Within a week, your period starts.
What will my cycle be like after a chemical pregnancy?
Medically, a chemical pregnancy is considered more like a normal cycle in which pregnancy did not occur than a “true” miscarriage. Your next cycle will likely be just like any other cycle, with ovulation at your usual time.