What Causes Recurrent Pregnancy Loss?

Most women do not like to talk about being pregnant until they have passed their first trimester. This is mainly because many pregnancies are lost in the first three months. There are certain factors that can cause a miscarriage. For some women, this is an issue that repeats itself every time they conceive. If a woman miscarries two or more times, it is termed as a recurrent pregnancy loss.

Causes of Recurrent Pregnancy Loss

Understanding the factors contributing towards repeat miscarriages can help prevent future miscarriages. There are many factors that can cause recurrent miscarriage. These include:

Genetic Factors

A healthy embryo or foetus typically has 46 chromosomes. These contain the genes necessary for the development of the foetus. However, in some cases, the foetus may have more or less than 46 chromosomes. For example, infants with Down Syndrome have 47 chromosomes. Some of these pregnancies can be carried till full term but in many cases, the pregnancy is naturally terminated in the first few weeks itself. Almost 60% of first-trimester miscarriages are caused by chromosomal abnormalities. The risk of having a miscarriage because of genetic factors is about 10-15% for women under the age of 35 years and about 50% for women over the age of 40 years.

Anatomic Abnormalities

If a woman's uterus is not shaped properly, the foetus may not get enough space to develop. This could lead to recurrent miscarriages. An abnormally shaped uterus could be the result of a genetic issue or a result of infections or prior surgeries. In other cases, anatomical abnormalities such as the presence of large fibroids or a band of tissue diving the uterus could also cause miscarriages. Many women are born with a septum diving the uterus into two parts.

Underlying Medical Issues

Untreated medical issues like polycystic ovarian syndrome, diabetes or thyroid dysfunction could also contribute to repeated miscarriages. Similarly, abnormal blood clotting systems or immune system abnormalities could also cause repeated miscarriages.

Lifestyle/Environmental Factors

Lifestyle factors that contribute to repeated miscarriages can be easily controlled and changed. For example, drinking too much caffeine or alcohol, smoking, and the use of recreational drugs like cocaine need to be avoided. These habits are causes of recurrent pregnancy loss. Similarly, being morbidly overweight or obese can also cause repeated miscarriages.

Along with the above, there are also many cases wherein the exact causes of recurrent pregnancy loss cannot be determined.