Repeat abortions

Miscarriage is defined as the loss of a pregnancy naturally in the first 20 weeks gestation.

The miscarriage rate is estimated to be approximately 15% in the general population. Very early pregnancy losses are frequently not diagnosed as they occur before menstrual delay and go unnoticed. After assisted reproduction techniques, very early abortions are detected more by the early determination of the pregnancy hormone in the blood.

Abortions according to age groups have different rate of appearance: in those under 30 years old it is between 10-15%, between 30 and 34 years old between 10-21%, between 35 and 39 years old between 15-28% and in those over 40 years old between 30-50%.

Causes of repeat abortions

First of all, and as always in reproduction, a detailed should be done in addition to the gynecological history, possible exposures to toxins, family history, history of thrombosis, and request the necessary tests for the study. The first test to ask for is a general analysis, which also includes specific values ​​to rule out some of the possible causes of repeat abortions already stated.

Genetic motives

Genetic causes of repeat abortions can be due to alterations of one or more genes or by alterations in the chromosomes. Eggs and sperm have 23 chromosomes each. When fertilization occurs, the new embryo will have 46 chromosomes in each cell, resulting from the sum of the 23 chromosomes of each of the two sex cells.

Chromosomal diseases are the alterations in the number or structure of chromosomes. To study the chromosomes of the couple, a blood karyotype study is requested. In 5% of couples there is some alteration of the chromosomes, which cannot be corrected in adults, but genetic counseling can be requested and a preimplantation diagnosis may be chosen, or by healthy donor eggs or sperm.

Endocrine factors

Endocrine factors are those in which hormonal changes occur and they are found in 15-20% of patients. diabetes and are one of the causes of pregnancy loss, so good control of these diseases should be achieved before a new pregnancy.

In addition, the syndrome polycystic ovary and luteal phase deficiency, which can be detected with hormonal tests in different phases of the cycle or with endometrial biopsies, can be the cause of recurrent pregnancy losses. Treatment of these causes is usually ovulation induction and progesterone treatment in the second phase of the cycle.

Infections

Infections can be a cause of miscarriage, but more rarely repeat abortions. In any case, in the study of this pathology, serologies are requested to rule out certain infectious diseases such as hepatitis, syphilis…. Cultures of the vagina, the cervix, and in some cases the uterine cavity are also requested.

Other alterations

10% of cases present antibodies3 against substances found in the membrane of the body's own cells, causing alterations in coagulation. These antibodies produce the so-called antiphospholipid syndrome, and for its study the lupus anticoagulant, anticardiolipin and anti beta2 glycoprotein antibodies are requested. If they are positive, the pregnancy should be treated with low-dose aspirin, adding in some cases heparin.

Thrombophilias are alterations in blood clotting and can be congenital, that is, at birth, or acquired, which appear throughout life. These alterations can be studied by specific analytics. Are studied protein C and S and antithrombin III whose function is to prevent the production of blood clots. If they are below the normal value, they can cause abortions due to thrombosis in the vessels of the placenta or the fetus.

Several genes regulate that the production of is not excessive and when they are altered, repeat abortions can occur.

These genes are studied in blood tests and are factor V of Leyden, factor II of prothrombin and MTHFR (methyltetrahydrofolate reductase), the latter related to the metabolism of homocysteine. As in antiphospholipid syndrome, if these alterations are found, treatment with aspirin and / or heparin is recommended during future pregnancies.

Anatomical factors are studied with various imaging techniques such as ultrasound, hysterosalpingography, 4 magnetic resonance imaging, or hysteroscopy. Malformations of the uterus can be found, such as the bicornuate uterus, the didelphys, the septum uterus. The appearance of processes that deform the uterine cavity such as polyps, fibroids or uterine adhesions can also be detected and in some cases treated with surgery.

Of interest: finally, male factors should be studied, so a basic study of semen should be requested and in some cases more complex studies such as the study of meiosis in testicular biopsy already described in the chapter on infertility due to male factors.