This scenario is all too common: your period is a few days late. A positive pregnancy test confirms that you are pregnant, but a in a matter of days or weeks, your period starts, and you no longer see two pink lines on a pregnancy test. What you’ve experienced is known as a chemical pregnancy loss.
What is a Chemical Pregnancy?
A chemical pregnancy, also known as a biochemical pregnancy, is a very early pregnancy loss taking place within five weeks after implantation. Many women who have a chemical pregnancy (don’t even realize they’ve conceived, since often the only sign is a late period.
During a chemical pregnancy, the body produces enough of the reproductive hormone, hCG (human chorionic gonadotropin), to initially result in a positive pregnancy test. However, at this early stage, the pregnancy cannot be detected on an ultrasound scan, and ultimately implantation will fail and serum hCG levels will decline.
What Causes Chemical Pregnancy Loss?
In most circumstances, there is no determinable cause of chemical pregnancy loss. In reality, most chemical pregnancy losses are due to chromosomal abnormalities in the pregnancy. Normal embryos contain 46 chromosomes – 23 from the egg and 23 from the sperm. Sometimes the embryo will have too few or too many chromosomes (also known as aneuploidy), which could lead to miscarriage or failed implantation. Approximately 70-75% of miscarriages are caused by chromosomal abnormalities.
Additional causes of chemical pregnancy loss include:
- Implantation outside of the uterus
- Blood clotting disorders
- Inadequate lining of the uterus
- Uterine fibroids (benign uterine tumors)
- Hormonal imbalances
- Thyroid dysfunction
- Autoimmune disorders with serum antibodies to specific proteins related to lupus
- Abnormal shape of the uterus (present from the time of birth)
Chemical Pregnancy Signs & Symptoms
The only way to confirm a chemical pregnancy is with a positive pregnancy test. A chemical pregnancy usually does not have any symptoms other than late a period, but some women may experience more cramping than normal or a heavier menstrual flow. Many women who experience a chemical pregnancy may not have even known they were pregnant.
Since your pregnancy hormone levels are present but low, women typically don’t experience any of the other signs of pregnancy, such as fatigue or nausea.
Chemical Pregnancy Treatment
A chemical pregnancy does not usually require medical intervention or treatment. However, you may pass some small blood clots. If you are actively trying to get pregnant, there’s no medical or physiological reason to delay trying to conceive after experiencing a chemical pregnancy.
How Common Are Chemical Pregnancies?
About 50-75% of all miscarriages are believed to be chemical pregnancy losses. While chemical pregnancy losses are common, if you’ve experienced several chemical pregnancies, you should consult a CCRM fertility specialist to help determine the potential cause of the losses.
Fertility Treatment After Chemical Pregnancy Loss
Depending on your diagnosis and unique circumstances, your physician can guide you on a path to a successful pregnancy. For women that have experienced multiple miscarriages, in vitro fertilization (IVF) with comprehensive chromosome screening (also known as CCS or PGT-A) may be explored. With this technique, CCRM can screen the embryos and select, transfer the embryos with the correct number of chromosomes, and significantly decrease your chances of miscarriage. [You might also be interested in: Recurrent Miscarriage]