What Is a Biochemical Pregnancy?

In a biochemical pregnancy, there's embryo implantation which increases beta-hCG. Spontaneous abortion occurs before the fifth week.
What Is a Biochemical Pregnancy?
Leidy Mora Molina

Written and verified by the nurse Leidy Mora Molina.

Last update: 02 October, 2022

A biochemical pregnancy, also known as a spontaneous abortion or a biochemical miscarriage, occurs when a miscarriage occurs before the fifth week of gestation. But why does it occur and how can we identify it? Learn more about this topic below.

In this type of pregnancy, the process of fertilization between the sperm and the egg the embryo is formed and implantation occurs in the uterus. This causes the beta-hCG (human chorionic gonadotropin) hormone to begin to be secreted. The elevation of this hormone causes pregnancy tests to be positive. However, the embryo stops growing early and this hormone stops increasing, resulting in biochemical miscarriage or expulsion of the embryo, which is often mistaken for menstrual flow.

This miscarriage occurs before the fifth week, therefore, the embryo isn’t observed by ultrasound. In this type of pregnancy, it’s common for the mother to not even discover her pregnancy status unless she is trying to conceive and undergoes early pregnancy tests. Miscarriages occur in 10 to 20% of all pregnancies. Of these, 50-75% are biochemical pregnancies. This condition can occur in natural gestations or in women who have undergone in vitro fertilization.

What causes a biochemical pregnancy to occur?

In a biochemical pregnancy, knowing the exact cause can be complicated. As the embryonic remains are eliminated with the menstrual flow, they’re not analyzed. Even so, these are the main reasons why spontaneous abortion commonly occurs:

  • Chromosomal abnormalities of the embryo
  • Anatomical problems in the uterus
  • Deficiency of the corpus luteum, which is responsible for secreting progesterone in the ovary
  • Low hormone levels, as in the case of progesterone deficiency
  • Vaginal infections such as chlamydia or syphilis
  • Clotting problems

Similarly, other causes related to the mother should be highlighted, such as age (over 35 years old) and if she suffers from chronic diseases such as thyroid diseases. In addition, an unhealthy lifestyle of the parents can also trigger a biochemical miscarriage. For example, a biochemical miscarriage can occur as a result of stress, alcohol, drug, and tobacco use.

A woman sitting on the couch with her hands over her abdomen, looking ill.
In general, there are no symptoms when a biochemical pregnancy occurs. However, they’re often mistaken for menstrual discomforts, such as abdominal pain, minor cramping, or vaginal bleeding.

Biochemical pregnancy symptoms

Women who experience a biochemical pregnancy usually don’t experience any pregnancy symptoms. In other words, they don’t experience nausea, drowsiness, or fatigue due to the pregnancy’s short duration. The symptoms are often confused with the discomforts of menstruation, among which we can highlight the following:

  • Abdominal pain similar to menstruation
  • Heavy and bright red vaginal bleeding that lasts several days
  • Passing of clots
  • Small cramps that radiate to the lower back

The treatment of biochemical pregnancy

A biochemical pregnancy doesn’t require specific treatment, the use of drugs, or the performance of uterine curettage. As the loss takes place very early, the body expels the fetal cells on its own. In these cases, menstruation usually takes place without altering the cycles.

Although this is usually a natural miscarriage resulting from chromosomal problems of the embryo, it’s important to know what may have caused it in order to avoid a recurrence in the future. For this reason, it’s important to be evaluated by a specialist.

Is pregnancy possible after a biochemical miscarriage?

Any woman who has had a biochemical pregnancy can become pregnant again, as this doesn’t reduce fertility cycles or the possibility of achieving a full-term pregnancy. This can be attempted after about two menstrual periods, but the important thing is for a specialist to approve this after evaluation.

Likewise, the woman should feel prepared to try a new pregnancy. In general, many parents are affected emotionally after a biochemical pregnancy, so a prudent time is required to heal emotionally.

Two women smoking.
Having a healthy lifestyle contributes to the prevention of suffering a biochemical pregnancy. Therefore, it is recommended not to smoke or consume drugs or alcohol.

Can a biochemical pregnancy be prevented?

As we’ve seen, 20% of pregnancies end in miscarriages without a specific cause, although they generally occur due to chromosomal problems of the embryo. For this reason, it’s important to have a healthy lifestyle, a balanced diet, and consume nutritional supplements.

In preconception consultations, the doctor assesses the anatomical conditions of the reproductive system, hormone levels, such as progesterone, and other conditions that need to be treated before seeking a pregnancy. If you know you’re expecting a baby, it’s important to take certain precautions to prevent a biochemical miscarriage:

  • Don’t use alcohol, drugs, or tobacco, and limit caffeine intake.
  • Avoid sexual intercourse if you suspect pregnancy until evaluation with the specialist.
  • Don’t exert yourself physically.
  • Rest if your body needs it.
  • Avoid taking drugs without medical authorization.
  • Take vitamins and folic acid for better cell multiplication and formation of the baby.

Visit a specialist to talk about your doubts

Regarding women who undergo in vitro fertilization and suffer biochemical pregnancy, some studies have shown that those who try again have a higher probability of pregnancy, which means that they can still conceive.

Ideally, you should discuss all the doubts you have regarding this issue with your specialist doctor. This will make you feel more at ease and you’ll be better prepared for pregnancy.

It might interest you...
5 Symptoms of Miscarriage
You are Mom
Read it in You are Mom
5 Symptoms of Miscarriage

It's important to recognize the symptoms of miscarriage in order to see a physician for diagnosis and appropriate treatment. Learn more.



  • Carp, H. (2020). Biochemical pregnancies: how should they be interpreted?. Gynecological and Reproductive Endocrinology and Metabolism 2020; 1(1):04-07
  • Jude, J. (2013). Biochemical Pregnancy During Assisted Conception: A Little Bit Pregnant. J Clin Med Res. Vol 5. Nº 4: 269-274.