What Is a Chemical Pregnancy?
Medically reviewed by Breanna Herring, Certified Nurse Midwife (CNM).
One of the most common types of pregnancy loss is a chemical pregnancy, or biochemical pregnancy. This results in a positive pregnancy test, but a failure of the pregnancy to continue progressing through the early part of the first trimester.
As common as chemical pregnancies may be, the causes remain only partially known. However, there is medical research available that can help us understand the phenomenon.
How Does a Chemical Pregnancy Occur?
According to the American Pregnancy Association, “a chemical pregnancy is an early miscarriage that usually happens before the pregnancy reaches five weeks.” This type of miscarriage is called a chemical pregnancy because the hormone human chorionic gonadotropin (HCG), which detects pregnancy, is detectable in the urine or blood, but evidence of a pregnancy is not visible on ultrasound.
This complication occurs when there is a fertilized egg, and the body has formed an embryo and started the process of implantation, but no further development of the embryo occurs. This fertilization and implantation signal your body to produce the HCG that is detectable as a positive result on a home pregnancy test.
With the advancement of home pregnancy tests, even low levels of HCG can generate a positive test result. The difference between a healthy pregnancy and a chemical pregnancy is that chemical pregnancies typically do not make it past the full implantation stage, making it impossible for the embryo to continue developing.
A chemical pregnancy may be diagnosed after a positive result followed by bleeding which occurred a few days or weeks afterward. It may also be diagnosed by a health care provider if the pregnancy hormone levels do not increase as expected over time. In other cases, a chemical pregnancy is not diagnosed until an ultrasound reveals that there is no evidence of a gestational sac inside the uterus.
What Are the Signs and Symptoms of a Chemical Pregnancy?
Because this type of early pregnancy loss occurs so soon after an egg is fertilized, many people who experience a chemical pregnancy do not yet realize that they are pregnant. This can occur so early that they have not yet had a positive result on a home pregnancy test.
If a pregnancy is suspected or confirmed with a home pregnancy test, a visit to a healthcare professional can help determine if you’re experiencing a normal or chemical pregnancy through routine blood tests, pelvic exams, and prenatal ultrasounds.
Signs and symptoms of a chemical pregnancy may include
- Late periods
- Heavier bleeding than is typical for a period
- Menstrual-like cramps
- Low HCG levels in the blood, or HCG levels that do not increase as expected over time
- Few or no clinical pregnancy symptoms, such as morning sickness or breast tenderness
Causes and Risks Associated with Chemical Pregnancy
The most common cause of a chemical pregnancy is a chromosomal abnormality. We can think of it as our body’s way of knowing if there’s something amiss with the chromosomes needed to grow a healthy baby. Other risk factors for chemical pregnancy include
- In vitro fertilization (IVF)
- Sperm DNA abnormalities
- Thin uterine lining that is not sufficient for proper implantation of the embryo
- Pregnancy conceived with an IUD in place
- Polycystic ovary syndrome (PCOS)
- High blood pressure, diabetes, blood clotting disorders or thyroid disorders
- Advanced maternal age (beyond 35 years)
As mentioned earlier, most chemical pregnancies miscarry spontaneously and completely through bleeding that can be light enough to mimic a period, or sometimes through heavy vaginal bleeding. Often this bleeding is coupled with cramping and clotting.
While most of these pregnancies pass on their own, there are times when medical intervention is needed, particularly when risk factors are present. If heavy bleeding occurs, this can result in a hemorrhage that can lead to anemia.
Seeking the advice of a healthcare professional is always the safest route to reduce the risk of complications that can have serious medical consequences or negatively affect the chances of later healthy pregnancies.
What Happens After a Chemical Pregnancy Has Occured?
If you have experienced a chemical pregnancy, there is nothing you have done wrong and you should not blame yourself for what has happened. Experiencing a chemical pregnancy can be a very distressing and overwhelming experience for many – make sure to lean on trusted family and friends during this time.
Most people who experience a chemical pregnancy recover without any physical complications and go on to have healthy pregnancies and babies later on.
While you cannot cause a chemical pregnancy, and there is no individual action that can prevent a chemical pregnancy, managing any health conditions or existing risk factors before future pregnancies may reduce the risk of recurrence.
Some healthcare providers may suggest waiting a minimum of three months before attempting to get pregnant after an early pregnancy loss, but recent medical studies have shown that this recommendation is not necessary for most people and does not seem to increase the chance of future pregnancy success.
The Emotional Effects After Pregnancy Loss
As with any pregnancy loss, the emotional aspects of a very early miscarriage due to a chemical pregnancy can be just as difficult to deal with, or even harder, than the physical effects.
People who have experienced pregnancy loss often experience sadness, depression, nightmares, anxiety, and an aversion or fear of getting pregnant again. And in many countries, including the US, people may be blamed or made to feel responsible for the loss of their pregnancies.
One of the reasons for these feelings lies within the stigma of pregnancy loss itself. That’s one of the reasons why the World Health Organization encourages open discussion on the topic of pregnancy loss and often shares stories to help people who have lost a pregnancy see that they are not alone and that grieving is a natural part of the process.
Being surrounded by compassionate family and friends, as well as seeking the support of therapists or support groups aimed at supporting people after the loss of a pregnancy can ease the pain and help people move forward in a healthy manner.
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