By Zaira Salvador BSc, MSc (embryologist) and Gorka Barrenetxea Ziarrusta MD, PhD (gynecologist).
Last Update: 09/19/2018

A chemical pregnancy, also known as biochemical pregnancy, is a very early miscarriage that usually goes unnoticed and is confused with the menstrual period.

For fertilization to take place, the sperm has to meet the egg in the Fallopian tube. If it happens, an embryo starts developing until it reaches day 6—at this point, it is time for the embryo to attach to the woman’s uterus. After implantation, the body starts releasing beta-hCG hormone, which is measured by pregnancy tests. As long as there’s a certain level of hCG in the body, tests will came out positive.

A chemical pregnancy can occur both in cases of natural conception and In Vitro Fertilization (IVF) pregnancies. In both cases, the symptoms are the same.

Chemical pregnancy after IVF

There is a common belief that a chemical pregnancy can only occur after undergoing an infertility treatment because it is often detected after taking a blood pregnancy test at a clinic.

Actually, the rate of chemical abortion after IVF is just as low as 8%.

For this reason, as one shall see, the chances for a chemical pregnancy to occur with IVF are as high as in natural pregnancies. The explanation behind this common misconception is simple: it happens so early that it goes unnoticed by the woman, who confuses it with her menstrual flow.

You can make a guess if you obtain a positive result after taking a pregnancy test but the levels of hCG don’t continue to rise exponentially after a few days.

hCG levels rising very slowly or not rising at all may indicate that a chemical pregnancy has taken place.

What are the causes?

This type of miscarriage or pregnancy loss occurs so early that the fetus cannot be seen by ultrasound scan. Finding out the causes that have led to early embryo arrest and miscarriage is complicated. The fact that the body passes the remaining tissue along with menstrual flow makes it impossible to be analyzed.

However, the following are some factors that may explain the mechanism of chemical pregnancies:

  • Embryonic gene alterations after fertilization
  • Genetic abnormalities in the egg and/or sperm
  • Unhealthy lifestyle habits of the parents: tobacco, alcohol, high levels of stress, etc.
  • Uterine malformations
  • Infections

We recommend that you try not to become obsessed with discovering the cause behind it, as it can be highly frustrating. The cause of some chemical pregnancies is just that, from time to time, certain embryos can’t continue developing for unexplained reasons, which does not mean that you are infertile.

Instead, you should be optimistic and see it as a good sign, given that fertilization and embryo implantation happened.

Signs & symptoms

Given that it occurs so early, there aren’t many symptoms associated with chemical pregnancies. However, the following are the most common ones:

  • Period-like abdominal pain
  • Bright red menstrual bleeding
  • Menstrual clots
  • Mild uterine contractions and back pain

There are no specific medications to take after a diagnosis of chemical pregnancy. Neither is a D&C (Dilation & Curettage) required. Your menstruation will show up as usual, and your ovulation periods will continue to be as always.

Ovulation after chemical pregnancy

The majority of women who have gone through a chemical pregnancy wonder whether it will affect their future fertility as well as how long should they wait before trying to conceive again.

A chemical pregnancy does not increase or diminish the chances of becoming pregnant again in the future. In the case of IVF patients, the success rates of your next cycle won’t be compromised either. In fact, given that the rates are cumulative, your chances will be higher.

Read: How Successful Is IVF with ICSI? – Pregnancy & Live Birth Rates.

Even though, in principle, you have a favorable prognosis after a chemical pregnancy, it is totally normal to feel devastated after going through such a complicated process. Keeping this in mind, we strongly recommend that you talk with your doctor to be aware of the real consequences of a chemical pregnancy and to learn what options you havr to fulfill your dream of starting a family.

If you need to undergo IVF to become a mother, we recommend that you use "The Calculator". In 3 simple steps, it will show you a list of clinics that fit your preferences and meet our strict quality criteria. Moreover, you will receive a report via email with useful tips to visit a fertility clinic for the first time.

Also, the report will inform you about the promotions or special prices that the clinics selected offer so you can benefit from them as well.

Interview to Gorka Barrenetxea, MD, PhD

Dr. Gorka Barrenetxea explains in the following video everything you need to know about this type of miscarriage, from the causes to the chances of pregnancy in these cases:

FAQs from users

When does ovulation occur after a chemical pregnancy?

By Zaira Salvador BSc, MSc (embryologist).

Typically, the menstrual cycle of a woman resumes within 1 or 2 weeks after a chemical pregnancy. However, this depends on whether hCG and progesterone are still present in your system. For the menstrual cycle to start again and ovulation to take place, your hormonal levels should drop to zero.

How long should we wait to try to conceive again after a chemical pregnancy?

By Zaira Salvador BSc, MSc (embryologist).

It varies on a case-by-case basis, and is highly dependent on how you feel emotionally and the causes of the chemical pregnancy. If your menstrual cycle resumes with normality, you can start trying to conceive again after two menstrual cycles. In any case, my advice is that you talk with your doctor previously.

Is it true that you are more fertile after a chemical pregnancy?

By Zaira Salvador BSc, MSc (embryologist).

No, it is not necessarily associated. However, in cases of IVF treatments, it is true that your chances of becoming pregnant, as long as the cause is not related to other problems, will increase because the success rates are cumulative.

Is a biochemical pregnancy considered a miscarriage?

By Zaira Salvador BSc, MSc (embryologist).

Yes, it is a type of miscarriage that occurs very early, even before anything can be seen in the uterus or on ultrasound. The only evidence is the presence of hCG in the body, which causes the test to be successful.

How can you tell if you have had a chemical pregnancy?

By Zaira Salvador BSc, MSc (embryologist).

Actually, distinguishing between miscarriage bleeding and menstrual flow is very complicated, as there is almost no difference between them to the naked eye. Common signs include a delay in your period or a menstrual flow that is more abundant than normal, but not so heavy as to be seen by the woman. Only those who got a positive pregnancy test are able to tell if they have had a chemical pregnancy.

Suggested for you

We have explained that a chemical pregnancy can only be detected through a blood pregnancy test in order for hCG levels to be quantified. Continue reading here: What Are Normal hCG Hormone Levels during Pregnancy?

A chemical pregnancy is actually a type of miscarriage or spontaneous abortion. What do you know about it? Get more information here: Why Does a Miscarriage Happen? – Causes, Symptoms & Treatment.

We have made several references to the two-week wait or 2WW after an IVF cycle, which is defined as the time period between the embryo transfer and the pregnancy test. To learn more about it, click here: What is the Two-Week Wait (2WW)? – Tips to Survive It.

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Authors and contributors

 Zaira Salvador
BSc, MSc
Embryologist
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia (UPV). Embryologist specializing in Assisted Procreation, with a Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia (UV) and the Valencian Infertility Institute (IVI). More information
License: 3185-CV
 Gorka Barrenetxea Ziarrusta
Bachelor's Degree in Medicine & Surgery from the Public University of Navarra, with specialty in Obstetrics and Gynecology from the University of the Basque Country. He has over 30 years of experience in the field and works as a Titular Professor of Obstetrics & Gynecology at the University of the Basque Country and the Master's Degree in Human Reproduction of the Complutense University of Madrid. Vice-president of the SEF. More information
License: 484806591