Identifying Causes Of Recurrent Miscarriage

causes of recurrent miscarriage

Miscarriage, also called spontaneous abortion, is the spontaneous loss of the foetus before the 20 weeks of gestation, mostly happening in the first trimester of pregnancy. If pregnancy loss happens after 20 weeks, it’s called a stillbirth. And miscarriage is a natural event, unlike surgical or medical abortions. However, miscarriages are much more common than we realise. More than 10 percent of known pregnancies end in miscarriage in a year. The rate is much higher in unknown miscarriages that happen even before a person realises they are pregnant. This article explores a relatively uncommon type of miscarriage called recurrent miscarriage, its symptoms, causes, treatment, and risk factors.    

What is recurrent miscarriage?

Recurrent miscarriage occurs when a woman has two or more consecutive pregnancy losses. The American College of Obstetricians and Gynaecologists (ACOG) estimates that recurrent miscarriages are uncommon and it affects only one percent of women in the world. 

Symptoms of recurrent miscarriage

The symptoms of miscarriage can vary in individuals. And each miscarriage can show different symptoms to no symptoms. But the most common symptoms are heavy spotting, vaginal bleeding, mucus or tissue discharge from the vagina, severe abdominal cramps, and back pain. Nonetheless, it is feasible to show these signs without having a miscarriage. So, if you notice any of these symptoms repeating or escalating, it is wise to seek medical assistance to make sure that everything is alright. 

Risk factors of miscarriage

These are the traits or habits that can increase the chances of miscarriage. 

Age: Studies have shown a significant difference in the occurrence of recurrent miscarriage in women according to their age. The chances of miscarriage increase from 12 to 15% for women in their 20s to 25% for women in their late 30s. At the age of 40, the risk is about 40%, and this increases to 80% at the age of 45. That is, risk increases after the age of 30, becomes greater at 40 and is highest over 45. Most age-related miscarriages are due to genetics or uterine abnormalities.

Previous miscarriages: Women who had two or more miscarriages in a row are at higher risk of miscarriage.

Chronic health conditions: Women who have chronic health conditions like unmanaged diabetes, and issues with the uterus or cervix have a higher chance of miscarriage. 

Weight: Research has demonstrated that while a minor increase in body mass index does not increase the risk of miscarriage, underweight and overweight patients have a greater chance of miscarriage during pregnancy. 

Substance abuse: Individuals who smoke, or use heavy doses of drugs and alcohol also increase the risk. 

Causes of recurrent miscarriage

If you go through two or three miscarriages in a row, a medical examination is often found helpful. Doctors would then run a range of tests on both the mother and father to determine the cause. Chromosomal testing on the miscarried foetus and parents, auto-immune testing, blood clotting studies, sonography, testing for insulin resistance and diabetes, and testing of endocrine glands are the common tests done. Sometimes, even after testing, doctors fail to identify the cause. But always remember that more than two-thirds of women who have undergone two or three consecutive miscarriages will be able to successfully deliver a healthy baby without treatment. However, if the causes are found, we can prevent further occurrences of miscarriage and emotional stress.  

Genetic or chromosomal abnormalities

50-80% of recurrent miscarriages happening in the first trimester are mainly due to genetic or chromosomal abnormalities. Chromosomes are tiny structures made of protein and DNA that carry genetic information in our bodies. Genes determine almost all of the physical attributes of a person. So, during fertilisation, the embryo receives two sets of chromosomes, one from each parent. Chromosomal abnormalities occur when the foetus receives chromosomes that are fewer or larger in number than the normal count. Therefore, when the irregularities in the genes of either the mother or the father are passed on, it causes severe problems in the foetus or causes a miscarriage.

When miscarriages occur more than two times, it is recommended that both parents do a blood test (karyotype) to check chromosomal abnormalities. This enables the doctors to check the chances of a balanced translocation. Unfortunately, the chances of finding balanced translocation are limited to four per cent. And in some cases, doctors consider in vitro fertilisation with preimplantation genetic testing. In this case, there is a high chance of successful birth as the selection of a chromosomally normal embryo is possible.  

Uterine anomalies

Miscarriage can sometimes happen due to abnormalities in the uterus. Out of this, about 15 percent is due to problems in uterine structure. These abnormalities can either be congenital like having a double or a separate uterus, due to the development of polyps or fibroids, or intrauterine scarring. Cervical incompetence is also a reason for miscarriages. Doctors recommend scanning to check the length of the cervix, and depending on results and medical history, you may undergo cervical cerclage (cervical stitching). And rare occurrences of poor blood supply can also lead to miscarriages. 

There are several methods for identifying uterine anomalies. Pelvic ultrasound, saline infusion sonohysterography, hysterosalpingogram, hysteroscopy, and MRI are some of the valuable tools used. Proper evaluation by a medical or healthcare professional can help you in identifying and understanding the complications. And most of these can be rectified before conception, increasing the chances of a healthy delivery.   

Endocrine issues

The second major factor that has the potential to cause recurrent miscarriages are endocrine issues. This may include diseases connected to the thyroid and pituitary glands, diabetes, or polycystic ovarian syndrome (PCOS).

Any fluctuation in thyroid glands can cause hormonal imbalance. This is detrimental to conception as it obstructs the development of the uterine lining, which is essential for the implantation and nourishment of the embryo. Thyroid tests can be easily performed along with blood tests. Following medication alone can balance the thyroid levels.

An increase in the production of prolactin, a reproductive hormone released by the pituitary gland, can inhibit the secretion of follicle-stimulating hormone (FSH). With very low or no FSH the development of uterine lining is impossible. Doctors prescribe medicines like cabergoline and bromocriptine to make the prolactin levels normal.  

Luteal phase defect develops when the ovaries don’t produce enough progesterone or the underdevelopment of the uterine lining. It is hard to remain pregnant with LPD. Ovulation induction medicines like clomiphene citrate are given to treat LSD. Progesterone therapy is also beneficial in treating similar endocrine hormonal issues.

High blood sugar levels increase the chances of miscarriage. Changing diets, workout routines, and medicines are required to control diabetes.   

Autoimmune diseases

Autoimmune diseases are rare disorders that develop when an individual’s immune system wrongly produces antibodies to fight certain substances that are essential for clotting blood. Blood clotting disorders like antiphospholipid syndrome and systemic lupus erythematosus cause recurrent miscarriages. When the antibodies from the mother clot the blood flowing to the placenta, it prevents the development of the foetus and reduces the supply of oxygen and nutrients to the embryo. It is highly unlikely for the embryo to attain maturity in these conditions, which often leads to repeated miscarriages. 

Therefore, women who have faced miscarriages multiple times should be screened for any such disorders. Treatment involving aspirin and heparin therapy has been observed to help in the thinning of the blood. It’s a complicated treatment, so it should only be followed under the doctor’s guidance.

Environmental factors

The likelihood of miscarriage is high in women who are exposed to drugs, alcohol, cigarettes, and X-rays. Most of these are lifestyle diseases, while some are work-related. The drinking and smoking habits of the father can also impact the pregnancy. Maintaining a healthy lifestyle and choosing good habits can lower the risk of recurrent miscarriages. However, stress, depression, and other work-related issues do not appear to be associated with miscarriage.

Unexplained factors

Over half of the women with recurrent miscarriages have unexplained causes. That is, even after testing for all possible risk factors, the result would be normal. As they don’t have any critical conditions, there is no universal treatment recommended for them. They are more likely to have a successful pregnancy the next time.

There are no treatments to prevent miscarriages. But focusing on healthy habits, keeping any medical condition you have under control, and taking regular prenatal care are some ways to take care of your baby and yourself.


It is estimated that 10 to 20% of all known pregnancies end in miscarriage, while only 1% of the population experience recurrent miscarriages. Though certain risk factors like endocrine issues, uterine anomalies, and genetic abnormalities have been linked to recurrent miscarriages, it is also common to have no identifiable cause for repeated miscarriages. Even after two or three failed pregnancies, the chances of a healthy birth are still high, and usually with no further complications. That being said, it would be wise to receive medical help to determine and treat the issue. Pregnancy loss can be emotionally and physically exhausting. Therefore, staying emotionally healthy is equally important. Therapy or counselling can help both partners deal with complicated emotions and grief. As recurrent pregnancy loss can increase the risk of having additional miscarriages, it is important to stay strong to achieve your dream of having a baby.

Leave a Reply

Your email address will not be published. Required fields are marked *