A recurring miscarriage is considered infertility

Repeated miscarriages - what can be done about it?

Repeated miscarriages - what can be done about it?

Three miscarriages in a row - the causes should be investigated. Often it works the next time.

Losing a pregnancy is quite common, especially in the first twelve weeks. It is estimated that up to 40% of all pregnancies that have started develop only for a short time and that further development is then stopped by the body because something very fundamental about the early cell division and implantation in the uterus was not right. Of the pregnancies that survive the first quarter, only about 5 percent end in a miscarriage before the 24th week. And even fewer women experience a miscarriage two or three times in a row.

The WHO and the guideline valid in Germany speak of a "repeated spontaneous abortion" after three or more miscarriages, and the European Society for Fertility Medicine and Embryology [1] after just two miscarriages. One thing is clear: the younger a woman is, the more rare are miscarriages. At the congress of the German Society for Gynecology and Obstetrics in October 2020 in Munich, Prof. Dr. med. Nina Rogenhofer from Munich, what causes repeated miscarriages can have, what methods can help to recognize these causes, and what possibilities there are to ultimately achieve a stable pregnancy and a healthy child.

Even if it gets boring, this blog post again comes first: Smoking, a lot of coffee, stress, overweight and underweight are the main suspects for recurrent miscarriages. Women who have already lost one or two pregnancies should definitely detoxify before the onset of the next pregnancy, correct their body weight and eliminate at least some of the sources of stress.

Another important problem is an age over 35 years. Over a million pregnancies and births from the Danish population register were evaluated a few years ago and the age of women who had already had one, two, three or more miscarriages was examined. It turned out that women up to the age of 34 who had already experienced an abortion would have a second abortion with a probability of 15-18%. If the women were over 40, this probability rose to 40%. In women who had already experienced three consecutive miscarriages at this age, there was a 60-65% probability that the next pregnancy would also end in an abortion.

The main cause of early miscarriages at an advanced age are disorders in the chromosomes of egg and sperm cells and in the early cell division of the developing embryo, but also the fact that the mucous membrane of the uterus at this age can often no longer produce optimal conditions quickly enough to allow it the fertilized egg can implant successfully. In the case of miscarriages in the later months of pregnancy, there are other underlying mechanisms - see above.

Smoking as a cause of miscarriage is generally underestimated. A recent study in California found that the risk of miscarriage increased by 1 percent with every cigarette smoked daily. If the normal risk of miscarriage for a woman at the age of 25 is around 2%, smoking 10 cigarettes a day increases it to 12%, that is to say sixfold [2].

If smoking, old age, stress, overweight and underweight are excluded as causes of the miscarriage, there are a number of other possibilities:

  1. A disorder of the hormonal system
  2. A disorder of the thyroid function
  3. A disruption and activation of blood clotting
  4. A disorder in the immune system,
  5. A lack of trace elements, especially iodine and fluoride,
  6. Frequent infections of the vagina and uterus,
  7. Malformations of the uterus.

Disruption of the hormonal system

Women with repeated miscarriages should be examined for cysts in the ovaries, a glucose metabolism disorder, or too many male hormones. These changes, which speak in favor of PCOS [3], can usually be treated successfully medically. However, there is no detour around correcting the excess weight.

Thyroid dysfunction

The thyroid hormones and antibodies against the thyroid gland should definitely be determined. Both underactive or overactive as well as an autoimmune disease that affects the functioning of the thyroid gland can lead to miscarriages. Conversely, medical treatment can eliminate the causes of the miscarriage and significantly increase the chance of a successful pregnancy.

Disruption and activation of blood clotting

Sometimes blood clotting increases during pregnancy. Such a change can be proven by measuring laboratory values. Low-dose ASA from the beginning and throughout pregnancy helps greatly in reducing the risk of miscarriages caused by this disorder.

Disorder in the immune system

How often an excessive reaction of the immune system is the cause of repeated miscarriages has not been scientifically established. In any case, it has been proven that there can be an autoimmune reaction in the placenta and thus impaired formation of blood vessels in the placenta. Such an autoimmune reaction can be detected by measuring laboratory values. In these cases it is important to use ASA to ensure blood flow in the placenta and to inhibit excessive blood clotting. Medicines that intervene in the autoimmune reaction or change the immune system should only be used within scientific studies.

A lack of trace elements, especially iodine and folic acid

Iodine deficiency is common in Germany. And the supply of folic acid through diet is often not optimal either. Both trace elements are vital for the development of the embryo, and both are available as supplements in the pharmacy or as an additive in kitchen salt. If everything was not done before the first pregnancy to prevent a deficiency, this should be checked after the first miscarriage at the latest.


Vaginal infections are a common cause of miscarriage and premature birth. That is why there are routinely multiple searches for bladder infections in each pregnancy, and the acidity in the vagina is measured, which shows whether there are enough "healthy" bacteria in the vagina that can combat possible pathogenic germs. After repeated miscarriages it is imperative to search intensively whether there may be germs in the uterus, whether the cervix really closes tightly enough, and the search for pathogens during pregnancy should be carried out particularly carefully. This does not only apply to the genital area. Untreated periodontal disease can also increase the risk of miscarriage.

Changes in the uterus

In very rare cases there is an anatomical change in the uterus that cannot be detected by normal ultrasound. After repeated miscarriages, a 3D ultrasound examination of the uterus is therefore often carried out in order to discover such changes.

Author: Dr. med. Susanna Kramarz

Image copyright © Jenny Sturm / shutterstock


[1] ESHRE = European Society of Human Reproduction and Embryology

[2] Am J Epidemiol. 2014 Apr 1; 179 (7): 807-823.

Published online 2014 Feb 10. doi: 10.1093 / aje / kwt334

Systematic Review and Meta-Analysis of Miscarriage and Maternal Exposure to Tobacco Smoke During Pregnancy

Beth L. Pineles, Edward Park, and Jonathan M. Samet *

[3] PCOS = poly-cystic ovary syndrome