Recurrent Miscarriage: Causes, Evaluation, and Treatment

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Medscape General Medicine. 1998;1(3) 

In This Article

Editorial Comment: What Really Causes Recurrent Miscarriage?

I do not subscribe to the authors' apparent belief that more than 50% of recurrent miscarriages are due to coagulation or immunological factors. Any miscarriage is a psychologically, and sometimes physically, devastating event. This is even more the case when miscarriages are recurrent, or when miscarriage follows infertility treatment, and when a woman believes she is near the end of her reproductive life. And unfortunately, the incidence of miscarriage increases with age, from 15% at ages under than 25 years to 35% after age 38. Women treated for infertility with clomiphene and human menopausal gonadotropin typically have a miscarriage rate of 25%, which although high is probably no higher than in spontaneously pregnant infertility patients of similar age.[1]

The consensus among physicians about when to begin evaluation of recurrent miscarriage has changed, in part due to the older age of their patients, from after the third or fourth miscarriage to after the second miscarriage, as the authors indicate. Actually, the largest increase in occurrence of miscarriage comes after 1 miscarriage, rising from 13% with no previous miscarriage to 23% after 1 miscarriage, to 29% after 2 miscarriages, and to 33% after 4 miscarriages.[2] For this reason, many physicians believe that chromosome analysis should be performed on the products of conception, obtained by dilatation and curettage, in the first pregnancy in which embryo or fetal demise occurs rather than on the parents after several miscarriages have already occurred.

However, the percentage of miscarriages in which a chromosome abnormality is detected decreases from 70%-80% for a first miscarriage to 40%-50% after 3 or more miscarriages. Therefore, 50% of recurrent miscarriages may be preventable.

The thesis of the review by Bick and colleagues is that 50% or more of recurrent miscarriages are the result of hematological or immunological causes. The authors describe a series of blood tests -- many of which are unavailable except in a research setting -- that can cost more than $1000.

Many physicians would disagree with this viewpoint. The consensus among most scientists is that only approximately 6% of recurrent miscarriages are due to antiphospholipids or other blood disorders. The importance of immunological causes is also debated by many. Other factors that may be important causes of recurrent miscarriage, such as infection and lifestyle, are not discussed in this article.

Recurrent miscarriage is frustrating to patients and physicians alike. There is an almost uncontrollable urge to find a cause and prescribe treatment. All manners of investigation are welcome, but treatment should be used cautiously when its effectiveness has not been established in randomized controlled studies.

Richard P. Dickey, MD, PhD
Chief, Reproductive Technology Section
Department of Obstetrics and Gynecology
Louisiana State University School of Medicine
New Orleans, La.


  1. Dickey RP, Taylor SN, Curole DN, et al: Incidence of spontaneous abortion in clomiphene pregnancies. Hum Reprod 11:2623-2628, 1996.

  2. Naylor AF, Warburton D: Sequential analysis of spontaneous abortion, II: Collaborative study data show that gravidity determines a very substantial rise in risk. Fertil Steril 31:282, 1979.