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Chemical Pregnancy: Symptoms, Causes, and Prevention of Miscarriage

What is a chemical pregnancy? It’s a term for quite a common early pregnancy loss happening soon after implantation. Learn all about this condition – chemical pregnancy with our article!
A wooden figure of a woman with a void from which a red child fell.

What is a chemical pregnancy?

A chemical pregnancy is also known as biochemical pregnancy is a medical definition given to an early and spontaneous abortion or very early miscarriage that happens before the 5th week of the gestation. It is a normal pregnancy in which conception takes place after ovulation, the embryo implants and a pregnancy test is done to confirm pregnancy. However, a miscarriage happens before anything can be seen in the womb. The only evidence of confirming pregnancy is the chemical reaction that results in the test to turn positive. It typically happens about one week after your monthly period is due.

Chemical pregnancies may account for 50 to 75 percent of all miscarriages. Some women who ever experienced chemical pregnancy never actually find out they have conceived since the only real sign or symptom is a late monthly period. A chemical pregnancy is confirmed when an early pregnancy test reveals a positive result but later returns to be negative in a week or two. While a chemical pregnancy does not cause any physical harm to a woman’s body, it can still trigger feelings of sorrow, grief, and deep sadness.

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How common are chemical pregnancies?

For women in their childbearing years, the possibilities of experiencing a miscarriage can range from 10 to 25 percent. Chemical pregnancies are actually very common, happening in 50 – 60% of first pregnancies. Chemical pregnancies may account for 50-75% of all miscarriages. 

  • Advanced maternal age (over 35) affects the possibilities of miscarriage.
  • Women under the age of 35 have about a 15% chance of miscarriage.
  • Women who are 35 – 45 years of age have a 20 – 35 percent chance of miscarriage.
  • Women over the age of 45 can have up to a 50 percent chance of miscarriage.
  • A woman who has already experienced a miscarriage has a 25-percent possibility of having another.

Chemical pregnancy symptoms

Symptoms of chemical pregnancy vary between women. Some will not experience any symptoms at all. Others may experience the signs of chemical pregnancy mentioned below:

  • Bleeding with or without cramps (20-30% of all pregnancies undergo some bleeding in early pregnancy, with about fifty percent of those not ending with a miscarriage).
  • Passing clots from the vagina.
Young woman patient with a senior gynecologist during the consultation

Causes of chemical pregnancies

Chemical pregnancies happen when an egg becomes fertilized but the implantation isn’t completed. Such pregnancies are not uncommon and occur in 50-60% of first-time pregnancies. Scientists believe that most of the chemical pregnancies are caused by some form of chromosomal abnormality. Abnormal chromosomes result due to several factors like abnormalities in genes passed down by the father or the mother, poor quality of the egg or the sperm, or an abnormal cell division of the fetus. 

Additional potential causes of chemical pregnancies include:
  • Infections such as chlamydia or syphilis.
  • Luteal phase defect.
  • Uterine abnormalities (acquired and congenital).
  • Systemic ailment such as untreated thyroid disease.
  • Abnormality in hormone levels.
  • Inadequate uterine lining.
  • Low body mass index (BMI) .

Chemical pregnancy or implantation bleeding: What’s the difference?

Bleeding from a miscarriage (chemical pregnancy)

In general, bleeding associated with a chemical pregnancy which is a nonviable pregnancy or an impending miscarriage may start as a light spotting and then turn to excessive bleeding with visible clotting (dark red color clots), similar to a heavy period. Cramping and heavier bleeding are other signs of a chemical miscarriage. In many cases, the woman might pass the fetal tissue from the vagina in a chemical pregnancy.

Bleeding from implantation bleeding

In contrast, implantation bleeding appears as a light brown colored discharge with a lighter flow that will last only a few hours to a few days. In implantation bleeding, vaginal bleeding happens in a very small amount almost around ten days after conception. The bleeding is an indication of the fact that the fertilized egg has got attached or implanted itself to the uterine wall of the pregnant woman successfully.

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How long does chemical pregnancy bleeding last?

A woman early in her pregnancy may have a miscarriage and only experience bleeding and cramping for a few hours. But another woman may have miscarriage bleeding for up to a week.

A chemical pregnancy does not usually last long enough to trigger pregnancy-related signs and symptoms like vomiting, headache, fatigue and mood swings. This type of miscarriage is different from other miscarriages.

How to prevent chemical pregnancy

The most important treatment during or after a spontaneous miscarriage is to prevent infection and hemorrhaging. The earlier you are in pregnancy, the more likely your body will oust all the fetal cell by itself and will not need further medical treatments and procedures. If the body is unable to expel the entire fetal cell, the most common procedure performed to prevent infection and excessive bleeding is curettage and dilation. 

Since most of the miscarriages occur due to abnormalities in chromosomes, there is nothing specific that can be done to prevent them. However, one vital step to prevent it is a healthy lifestyle. Monitor and work on your health before conceiving to offer a healthy atmosphere for pregnancy to happen. Few steps one can take include:

  • Proper and regular exercise
  • Eating healthy food
  • Stress management
  • Monitoring weight and keeping it within healthy limits
  • Eating iron-rich food or take folic acid every day.
  • Avoid smoking and alcohol

Apart from these, some medical procedures can be adopted too in consultation with your doctor. These include:

  • Assisted reproductive technology (ART) or in vitro fertilization (IVF) and testing of embryos before implantation to confirm if the chromosomes are normal. This can be considered if you have experienced multiple miscarriages.
  • Women with the polycystic ovarian syndrome (PCOS) or irregular menstrual cycles may have inadequate female hormones to support the early stages of pregnancy and could benefit from hormone supplementation.

Once you realize that you have conceived, the goal is to follow a healthy lifestyle, to offer a healthy environment for your fetus to grow in. Here’s your basic checklist for early pregnancy:

  • Keep your lower abdomen safe.
  • No smoking and alcohol and avoid being in a smoke environment.
  • Consult your GP before consuming any over-the-counter medications.
  • Get your blood sugar under control (if you are diabetic).
  • Avoid exposure to environmental hazards like x-rays, radiation, and infectious diseases.
  • Eliminate or limit caffeine.
  • Avoid activities or contact sports which have a risk of injury.
Annan, J. J. K., Gudi, A., Bhide, P., Shah, A., & Homburg, R. (2013). Biochemical pregnancy during assisted conception: a little bit pregnant. Journal of clinical medicine research, 5(4), 269.

Arck, P. C., Rücke, M., Rose, M., Szekeres-Bartho, J., Douglas, A. J., Pritsch, M., ... & Nakamura, K. (2008). Early risk factors for miscarriage: a prospective cohort study in pregnant women. Reproductive biomedicine online, 17(1), 101-113.

Barlow, P., Lejeune, B., Puissant, F., Englert, Y., Van Rysselberge, M., Degueldre, M., ... & Leroy, F. (1988). Early pregnancy loss and obstetrical risk after in-vitro fertilization and embryo replacement. Human Reproduction, 3(5), 671-675.

Burton, G. J., & Jauniaux, E. (2004). Placental oxidative stress: from miscarriage to preeclampsia. Journal of the Society for Gynecologic Investigation, 11(6), 342-352.

Coulam, C. B., & Roussev, R. (2002). Chemical pregnancies: immunologic and ultrasonographic studies. American Journal of Reproductive Immunology, 48(5), 323-328.

Geva, E., Yaron, Y., Lessing, J. B., Yovel, I., Vardinon, N., Burke, M., & Amit, A. (1994). Circulating autoimmune antibodies may be responsible for implantation failure in in vitro fertilization. Fertility and sterility, 62(4), 802-806.

Larsen, E. C., Christiansen, O. B., Kolte, A. M., & Macklon, N. (2013). New insights into mechanisms behind miscarriage. BMC medicine, 11(1), 154.

Lee, H. M., Lee, H. J., Yang, K. M., & Cha, S. H. (2017). Etiological evaluation of repeated biochemical pregnancy in infertile couples who have undergone in vitro fertilization. Obstetrics & gynecology science, 60(6), 565-570.

Zeadna, A., Son, W. Y., Moon, J. H., & Dahan, M. H. (2015). A comparison of biochemical pregnancy rates between women who underwent IVF and fertile controls who conceived spontaneously. Human Reproduction, 30(4), 783-788.

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