A chemical pregnancy is a miscarriage that happens before five weeks, immediately after the embryo implants (1). It is a pregnancy that home pregnancy tests or blood tests may confirm but not seen on an ultrasound. It is also called a biochemical pregnancy (2).
Most women do not know they are pregnant when they have an early miscarriage.About 50-75% of all miscarriages are chemical pregnancies(3). Read this post to learn more about the causes, chemical pregnancy signs and symptoms, risk factors, and diagnosis of chemical pregnancies.
Symptoms Of Chemical Pregnancy
Chemical pregnancy symptoms may vary from one woman to another. While some women do not experience any symptoms, others may notice the following miscarriage symptoms (2).
- A positive pregnancy test that soon turns negative.
- Spotting for a week before the period is due
- Mildabdominal cramping
- Vaginal bleeding after a positive result
- Low HCG levels in a blood test
Causes Of A Chemical Pregnancy
While the exact cause is not always identifiable, it may happen due to one or more of the following reasons (3) (4).
- Chromosomal abnormalities in the embryo
- Inadequate hormonal levels
- Improper implantation
- Problems with the uterine lining (due to anatomical, immunological, or other reasons)
- Low maternal weight
- A problem with the DNA of the sperm
- Low progesterone levels
- Unsuccessful IVF
Chemical Pregnancy And Clinical Pregnancy
The main difference between a chemical and a clinical pregnancy is ultrasound can confirm a clinical pregnancy.A gestational sac and fetal heartbeat are seen in clinical pregnancy, whereas not detected in a chemical pregnancy.
Risk Factors For Early Pregnancy Losses
The following factors may increase one’s risk of experiencing a miscarriage early in pregnancy (5).
- Advanced maternal age
- Alcohol consumption
- Excessive caffeine consumption
- Cigarette smoking
- Cocaine abuse
- Blood clotting disorders
- Thyroid problems
- Certain maternal diseases—chlamydiaiXA bacterial infection spread through oral, anal, or vaginal intercourse,listeriaiXA type of bacteria that contaminates the food and causes listeriosis infection,syphilisiXA sexually transmitted bacterial disease, typically causing sores in the genital and oral regions, linked to fetal complications,toxoplasmosisiXAn infection caused by the Toxoplasma gondii parasite, typically found in undercooked meat, animal feces, and contaminated soil,vaginal mycoplasmaiXThe most common microorganisms to cause genital infections,ureaplasmaiXBacteria found in urinary or reproductive tracts and is primarily transmitted through sexual contact, etc
- Certain medications—venlafaxine, retinoids, paroxetine, NSAIDs, methotrexate, itraconazole, etc
- Obesity
- Previoushistory of miscarriages
- Abnormalities in the reproductive tract, such as uterine anomalies, short cervix, and uterine adhesions
- Exposure to toxins—pesticides, radiation, some gases, etc
Diagnosis Of A Chemical Pregnancy
Women who test positive in home pregnancy tests or blood tests and then test negative in the next few days might be asked to go for additional blood tests.If the pregnancy hormones show a declining pattern, it might indicate a chemical pregnancy (1). However, these blood tests are not suggested for all women.
Treatment For A Chemical Pregnancy
As many women are not aware of their pregnancy until five weeks of gestation, miscarriage from a chemical pregnancy may be misunderstood for a usual or a late period. While some women may experience a little heavier blood flow with clots, others may have a blood flow similar to their usual period.
For women with Rh-negative blood group, the healthcare provider may administer a shot of Rh immunoglobulin after experiencing a pregnancy loss.An Rh-negative mother with an Rh-positive fetus might face some complications that may be avoided by the shot(6).
These miscarriages occur early in the pregnancy, and for most women, they resolve naturally, and no treatment is needed. However, the recovery is quick, and the doctor may ask you to try again after one menstrual cycle (1) (2).
Prevention Of A Chemical Pregnancy
While it is not always possible to prevent a chemical pregnancy, addressing some risk factors or intervening for treatable health conditions can help prevent a chemical pregnancy (5)
Chemical Pregnancies And IVF
According to fertility experts, a chemical pregnancyafter an IUIor IVF cycle is a good sign. This is because assisted reproductive technologies aid in getting pregnant. However, whether or not implantation and pregnancy will happen depends upon the body’s and embryo’s natural processes. Therefore, some IVF specialists consider a chemical pregnancy as good news as it confirms a woman’s ability to get pregnant and is a sign of hope that they will get pregnant in the future.
常见问题s
1. How long do I bleed after a chemical pregnancy?
The duration of bleeding varies from woman to woman. In some, bleeding and cramping may last only a few hours, whereas, in others, it may last for a few days.
2. Can stress cause chemical pregnancy?
Chronic stress can adversely affect the health of the mother and her unborn baby. However, no direct link was found between stress and a chemical pregnancy.
3. Will I pass tissue with a chemical pregnancy?
The amount of blood a woman loses during chemical pregnancy varies. However, most women pass tissues from the uterus usually at the same time they have their period (8).
Experiencing a chemical pregnancy does not mean you will have more of them. It is common and normal to feel anxious after experiencing a chemical pregnancy. However, consult your doctor if you experience one or multiple chemical pregnancies.
Infographic: Causes Of A Chemical Pregnancy
Chemical pregnancy can be emotionally challenging. You learn you are pregnant and, after a few days, experience pregnancy loss suddenly. The infographic below explains the reasons why a chemical pregnancy may occur. Exploring the reasons behind a chemical pregnancy can provide insight and support for those affected by this early pregnancy loss.
Key Pointers
- A chemical pregnancy, also known as a biochemical pregnancy, is a type of miscarriage that happens when the embryo implants but is lost before five weeks of pregnancy.
- Chemical pregnancies account for over 50% of all spontaneous abortions.
- Symptoms of chemical pregnancy include abdominal cramps, spotting before the next period, and a positive pregnancy test that eventually turns negative.
- Possible causes of chemical pregnancy are improper implantation, chromosomal abnormality, low maternal body weight, and insufficient hormone levels.
- An ultrasound is used to confirm a clinical pregnancy.
References:
- Chemical pregnancy
https://www.tommys.org/baby-loss-support/miscarriage-information-and-support/types-of-miscarriage/chemical-pregnancy-information-and-support - Chemical pregnancy
https://www.miscarriageassociation.org.uk/information/miscarriage/chemical-pregnancy/ - Chemical Pregnancy: Here Are the Facts
https://rmccares.org/2019/10/08/chemical-pregnancy-here-are-the-facts/ - John Jude Kweku Annan et al; (2013); Biochemical Pregnancy During Assisted Conception: A Little Bit Pregnant
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3712881/ - Office Management of Early Pregnancy Loss
https://www.aafp.org/afp/2011/0701/p75.html - Early Pregnancy Loss
https://www.acog.org/womens-health/faqs/early-pregnancy-loss - Trying to conceive soon after a pregnancy loss may increase chances of live birth
https://www.nih.gov/news-events/news-releases/trying-conceive-soon-after-pregnancy-loss-may-increase-chances-live-birth - Early Pregnancy Loss.
https://familydoctor.org/condition/early-pregnancy-loss/