What Does a Positive Pregnancy Test After a Miscarriage Mean?

If you've had a diagnosis of miscarriage, you may be confused if you take a pregnancy test and find that it's positive. However, it's common to get a positive pregnancy test after miscarriage for a week, two weeks, or even a month. This type of false positive result has a few different explanations.

Keep reading to learn how a pregnancy test works and how long it usually remains positive after a miscarriage.

How Pregnancy Tests Work

Pregnancy tests detect the presence of the hormone hCG (human chorionic gonadotropin) in the blood or urine. High levels of hCG typically indicate pregnancy, with levels of the hormone rapidly increasing during the first 10 weeks after the fertilized egg attaches to the wall of the uterus.

However, after an embryo or fetus stops growing and a miscarriage occurs, the hormone does not disappear from a person's body right away. The level of hCG gradually decreases, falling back down to zero over a period of days, or even weeks, depending on how far along the pregnancy was when the miscarriage happened.

Because today's pregnancy tests usually detect very low levels of hCG, taking one in the days or immediate weeks after your miscarriage can still show a positive result. You may also continue to feel pregnancy symptoms after a miscarriage, even when it's confirmed that you have miscarried.

When Will hCG to Return to Normal?

You'll get a positive pregnancy test after miscarriage until your hCG levels return to normal. It takes an average of 12 to 16 days for hCG to disappear from the body, but this can vary based on how high your hCG level was at the time of your miscarriage. 

It can take around a week to return to zero with a chemical pregnancy (a very early pregnancy loss) and up to a month, or even more, with a miscarriage that occurs later in pregnancy. After that, a pregnancy test won't be positive.

Reasons for a Persistent Positive Pregnancy Test

Experiencing a miscarriage can be an emotional rollercoaster and the confusion over a persistently positive pregnancy test can add to this already difficult situation. Be assured that it can take a variable amount of time (on average two weeks) for a person's hCG level to disappear after a miscarriage.

If it has been more than a couple of weeks since your miscarriage, you should call your doctor if you are still getting a positive pregnancy test. In this situation, your doctor may want to monitor your hCG level with blood tests (a quantitative hCG). However, if you continue to have a positive blood pregnancy test, there are a few possibilities to consider.

You're pregnant again

If you've been sexually active and have a positive pregnancy test soon after a miscarriage, you might be pregnant again. Your doctor will be able to tell you, though they may need to follow up with blood hCG tests to know for sure.

Although many people are not aware of this, it's possible to become pregnant during your first menstrual cycle after a miscarriage. If you're not trying to become pregnant after your loss, you should use contraception to prevent pregnancy until you're ready.

Incomplete miscarriage

With an incomplete miscarriage, there's still pregnancy tissue left over in your uterus. Unfortunately, it does not mean that your pregnancy is continuing or is viable.

You may need a simple surgical procedure called a D&C (dilation and curettage) to remove the retained products of conception, which are usually only small pieces of the placenta. These tissues will probably be reabsorbed (broken down) by your body in time, but surgery can help put a stop to heavy bleeding sooner, as bleeding is a common symptom of an incomplete miscarriage.

Molar pregnancy

Very rarely, a positive pregnancy test may occur with gestational trophoblastic disease—a term used to describe several conditions (like a molar pregnancy) in which there is an abnormal growth of placental tissue.

If you feel like something isn't right, or you're experiencing heavy or persistent bleeding, worsening pelvic pain, or a fever with your miscarriage, seek medical guidance.

When Can I Get Pregnant After a Miscarriage?

In the past, it was thought that getting pregnant within three to six months of a miscarriage raised the risk of problems, ranging from toxemia to stillbirth. However, according to the National Institutes of Health, research doesn't support waiting that long.

In fact, studies suggest that you have a greater chance of getting pregnant if you start trying within three months of having a miscarriage, and your risk of complications isn't increased.