Why Do Miscarriages Happen?

2021-05-18T11:36:27-06:00May 18th, 2021|

Experiencing a miscarriage can be a devastating. You might be left wondering why it happened and what you can do to prevent another one. It’s important to understand they’re very common, about one in four pregnancies end in a miscarriage, and many times they occur very early in pregnancy without you even knowing. The further along you get into your pregnancy, the less likely a miscarriage will occur.

How does a miscarriage happen?

Most of the time a miscarriage occurs because of a chromosomal abnormality in the embryo. Most cells in the body have 23 pairs of chromosomes, but sometimes there might be an extra or missing chromosome from these pairs. These chromosome abnormalities are the cause of approximately 70% of miscarriages.

It can be a sensitive subject, but often these chromosome issues are related to age, or more specifically, the age of your eggs, especially in your mid-thirties and up. Females are born with all the eggs they’re ever going to have, and as she ages, both the quantity and quality of her eggs start to decline and the likelihood of a chromosomal abnormalities occurring increases. An embryo with an incorrect number of chromosomes it less likely to implant the uterus and is more likely to result in miscarriage.

The second most common reason for miscarriage is something called balanced translocation. This happens when parts of the chromosomes switch places. If one partner has this condition, it can cause recurrent miscarriages in 2 to 5 percent of couples.

A miscarriage is not something you caused. But there are a few non-genetic factors that can put you at a higher risk of miscarriage including infection, obesity, hormone imbalances, lifestyle factors, such as smoking, as well as uncontrolled diabetes.

Can you prevent a miscarriage?

Miscarriages can happen no matter how healthy you are and many times it’s due to a chromosomal abnormality that you can’t control. However, there are certain things you can do to lessen your risk of miscarriage. Avoid smoking and drinking alcohol, minimize your exposure to environmental toxins, and be at a healthy weight. If you have a medical condition that can affect pregnancy, such as thyroid conditions or diabetes, work with your health care team to make sure these are being managed. Focus on things you can control such as daily exercise, eating healthy, and drinking enough water. Most people who have had a miscarriage will still go on to have a successful pregnancy.

What to do if you’ve had multiple miscarriages?

Recurrent miscarriages, or recurrent pregnancy loss, means you’ve had three or more consecutive miscarriages. Your provider may want you to have some tests done to figure out if there’s a genetic reason for your miscarriages. Karyotyping is a blood test that helps your doctor uncover any issues with the size, shape, or number of chromosomes in you and your partner. You may also be able to test the embryo or miscarried tissue for any genetic abnormalities.

Comprehensive chromosomal screening (CCS), also known as preimplantation genetic testing for aneuploidy, is an effective treatment for individuals who have experienced multiple miscarriages. CCS can be done on embryos as a part of an in vitro fertilization (IVF) cycle. After the eggs are fertilized in the lab, several cells of the embryos are biopsied, and the chromosomes in the cells are counted. Only the embryos that have the correct number of chromosomes will be transferred to the uterus. IVF with CCS is an effective treatment for recurrent miscarriage. CCRM Fertility is proud to have some of the highest IVF with CCS success rates in the U.S.

While no one wants to have a miscarriage, it can help to know that most of the time, they’re out of our control. If you have had multiple miscarriages, we recommend making an appointment with a CCRM Fertility specialist to help you find out any potential causes and work with you on a personalized treatment plan.

Written by: Dr. Sara Barton, a board certified reproductive endocrinologist at CCRM Colorado

About CCRM

CCRM is one of the industry's leading pioneers in fertility science, research and advancement, offering access to a national network of award-winning physicians, a full suite of fertility services, innovative technology and cutting-edge labs.