1. Pregnancy
  2. Pregnancy health
  3. Miscarriage

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6 Common causes and 11 Risk factors of Miscarriage: What can You do to Prevent Pregnancy Loss?

Miscarriage refers to the spontaneous ending of a pregnancy before the 20th week of gestation. According to estimates by the American Pregnancy Association (APA) miscarriages happen in 10 to 25 percent of all pregnancies.

But the real number of miscarriages is likely greater as many of them happen quite early during pregnancy and by that time many women don’t get to know they were pregnant. Miscarriage is quite common, but it is undoubtedly a difficult experience. You can take a step forward and heal emotionally by understanding what could cause a miscarriage. The article discusses the various causes of miscarriage, risk factors of miscarriage and what you can do to prevent a miscarriage. 

Your body provides nutrients to the developing fetus during pregnancy to help with its normal development. One of the main causes of miscarriage during the first trimester is the abnormal development of a fetus. This may occur due to different factors.

Half of the miscarriages may occur because of chromosome issues. The errors occur randomly during the division of fetal cells.

They may also occur as a result of a damaged sperm or egg cell. 

Some examples of causes of miscarriage due to chromosomal abnormalities are:

  • The intrauterine demise of the fetus: There is a formation of the embryo but it stops developing before there is a development of any symptoms of miscarriage.
  • Blighted ovum: In this condition, there is no formation of an embryo. This is one of the reasons for early miscarriage. 
  • Molar pregnancy: in this condition, the father provides both sets of chromosomes, but there is no development of a fetus. Instead, there is an abnormal growth of the placenta. 
  • Partial molar pregnancy: In this condition, the chromosomes from the mother remain; but the father also provides two sets of chromosomes. It is associated with placental abnormalities and growth of an abnormal fetus.

Long-term health conditions of the mother may be one of the causes of miscarriage at 20 weeks of pregnancy.

Some of these health conditions include:

  • uncontrolled diabetes
  • thyroid disease
  • heart disease
  • hypertension
  • antiphospholipid syndrome
  • lupus and other types of immune system disorders
  • kidney disease.

Many infections in the mother may result in a miscarriage. These infections include:

  • chlamydia
  • gonorrhea
  • syphilis
  • malaria
  • German measles
  • AIDS

One of the causes of miscarriage during the second trimester of pregnancy is a weakened cervix also known as the incompetent cervix or cervical incompetence. In this condition, the cervical muscles are weaker and are not able to hold the fetus. It may occur as a result of a previous injury to the cervix such as after a surgery. Due to the weakness of muscles, the cervix may open too early often during the second trimester of pregnancy resulting in miscarriage.

Polycystic ovary syndrome (PCOS) is a disease in which multiple cysts are present in the ovaries making them larger in comparison to normal ovaries. It occurs due to hormonal changes in a female. It causes infertility in females as it reduces the production of eggs.

There's some evidence to suggest it may also be linked to an increased risk of miscarriages in fertile women.


Women 35 years of age or older may have an increased risk of miscarriage in comparison to younger women. The risk of having a miscarriage is about 20 percent when you are 35 years old, the risk increases to 40 percent at age 40 and to 80 percent when you are 45 years old.

Being overweight or obese may increase your risk of having a miscarriage.

If you smoke during your pregnancy, then your risk of having a miscarriage may get increased in comparison to nonsmoker women.

Drinking alcohol heavily during pregnancy may also increase the risk of having a miscarriage.

Use of illicit drugs during pregnancy may increase the risk of having a miscarriage.

Having an excessive amount of caffeine during pregnancy (more than 200 mg per day) may also increase the risk of miscarriage.

Food poisoning that occurs due to consuming contaminated foods may also increase your risk of having a miscarriage. For instance:

  • Listeriosis: It is most commonly present in unpasteurized dairy products; for instance, blue cheese.
  • Salmonella: It occurs due to eating partly cooked or raw eggs. 
  • Toxoplasmosis: You may get this infection by eating undercooked or raw infected meat.

Physical trauma may also increase your risk of having a miscarriage.

Taking certain medicines during pregnancy may also increase the likelihood of having a miscarriage. Some of these medicines are:

  • Misoprostol: It is given for the treatment of conditions such as rheumatoid arthritis.
  • Retinoids: It is given for skin conditions such as acne and eczema. 
  • Methotrexate: It is also given to treat autoimmune diseases such as rheumatoid arthritis. 
  • Non-Steroidal Anti-Inflammatory Drugs (NSAIDs): These drugs such as ibuprofen are given to relieve inflammation and pain. 

To make sure that a particular medicine is safe to take during pregnancy, always check with the pharmacist or physician before taking it. 

There are various types of infections that may increase the risk of miscarriage if you get them during pregnancy:

Several chronic diseases may increase the risk of miscarriage in the second trimester of pregnancy, particularly if they are poorly controlled or not treated and uncontrolled diabetes is one of them.

There are several misconceptions related to the miscarriage reasons in early pregnancy and the risk factors of miscarriage.

  • The emotional state of women during pregnancy: the emotional state of women during pregnancy including being depressed or stressed is not linked to the increased risk of having a miscarriage.
  • Having a fright or shock during pregnancy: if you suffer from a fright or shock during pregnancy, it may also not increase your risk of having a miscarriage. 
  • Exercising during pregnancy: exercising during pregnancy does not increase your risk of miscarriage. This includes doing high-intensity exercises such as cycling and jogging. But you should definitely discuss the kind and amount of exercise you may do during pregnancy with your physician or obstetrician. 
  • Straining or lifting during pregnancy: lifting and straining do not really increase your risk of miscarriage.
  • Working during your pregnancy: you don’t have to stop working, even if your work involves standing or sitting for a long time as working during pregnancy is not connected to the likelihood of having a miscarriage. However, you should make sure that you have no exposure to harmful radiation or chemicals at work. Discuss with your physician if you have concerns about any risks related to work.
  • Having sexual intercourse during pregnancy: having sex is not among the reasons for miscarriage. So, you may enjoy sex with your partner during pregnancy for as long as you feel comfortable. 
  • Air travel during pregnancy: air travel is not harmful to pregnancy and is considered safe; therefore, pregnant women are allowed to travel by air until the 36th week of pregnancy by most commercial airlines. 
  • Eating hot and spicy food: eating hot and spicy food may neither cause a miscarriage nor increases your risk of having it.

In many cases, causes of miscarriage aren’t known; hence, you can’t prevent them. But you may reduce your risk of having a miscarriage. Here are the ways to reduce the risk of miscarriage by controlling the possible causes:

  • Not smoking tobacco during pregnancy
  • Not drinking alcoholic beverages during pregnancy
  • Not using illicit drugs while pregnant
  • Eating a well-balanced and healthy diet 
  • Making sure to avoid getting infections such as rubella while pregnant
  • Avoiding contaminated foods while pregnant as these may cause food poisoning and increase the risk of miscarriage 
  • Attaining your healthy or optimum weight before conceiving
  • Treating the identifiable causes such as antiphospholipid syndrome or weakened cervix may also prevent miscarriage

A miscarriage may have a great emotional impact on the woman and her partner, family, and friends. You may ask for support and advice during this hard time. You may feel the emotional impact of the miscarriage immediately or after several weeks. You may feel fatigued, and have reduced appetite, and difficulty in sleeping after having a miscarriage. You may develop feelings of sadness, shock, guilt, and anger. Different women grieve after a miscarriage in different ways. Some may feel better by talking about what they feel while others may find it too painful to talk about the subject. 

Find out what you can do with our Health Assistant

If you and your partner are finding it difficult to cope with the loss of a miscarriage, you may go to a counselor for counseling sessions. 

Miscarriage refers to the spontaneous ending of a pregnancy before the 20th week of gestation. There are many common reasons for miscarriage including genetic or chromosomal issues, placental problems, and long-term health conditions of the mother, infections, weakened cervix, and PCOS. There are several factors that may increase the risk of miscarriage in women. These include increasing age, excessive weight, smoking during pregnancy, drinking excessive alcohol and using illicit drugs during pregnancy, having excessive amounts of caffeine during pregnancy, food poisoning, physical trauma, taking certain medicines, infections, and having uncontrolled diabetes. There are several misconceptions related to the causes of miscarriage and its risk factors. You may reduce the risk of miscarriage by controlling some causes of miscarriage such as not smoking, not drinking alcohol, not using illicit drugs, eating a healthy diet, getting to a healthy weight during pregnancy etc. Recovery from miscarriage may be quite painful. You may feel fatigued and tired and develop feelings of shock, sadness, and anger. Get help from a counselor if you find it difficult to cope with a miscarriage.