Miscarriage is the involuntary termination of pregnancy before the 20th gestational week. One in every 4-5 women experiences a miscarriage. However, recurrent miscarriage, defined as 2 or more pregnancy losses, is observed in only 1-2% of women.
In other words, a miscarriage is generally not a recurring condition. However, maternal age is an important determinant. The risk of miscarriage increases as age advances, reaching 50% in women over the age of 40.
It can be difficult to determine the cause of miscarriages that occur within the first 12 weeks. Polycystic ovary syndrome, congenital or later-acquired uterine abnormalities (uterine septum, adhesions, polyps, or myomas), genetic problems in the expectant parents, the mother’s coagulation system disease, uncontrolled diabetes and thyroid disease, or infections can be causes of miscarriage.
More than half of pregnancy losses in the first 12 weeks occur due to genetic problems. In miscarriages occurring between the 12th and 20th weeks of pregnancy, cervical insufficiency and the mother’s health problems frequently play a role.
Furthermore, when vaginal infections during pregnancy are left untreated due to the anxiety that “treatment might harm the baby,” they may cause preterm premature rupture of membranes in the following weeks. When a woman who has had a miscarriage consults her gynecologist before becoming pregnant again, vaginal, uterine, tubal, and ovarian pathologies are investigated during routine examination and ultrasonography.
Existing infections must be treated. If there is a suspicious tubal or uterine image on ultrasound, a uterine film (hysterosalpingography) should be requested. Additionally, if myomas seen in the uterus are located towards the internal cavity of the uterus, they must be removed with a procedure performed using an endoscopic light device called hysteroscopy.
What is the Effect of Myomas on Miscarriages? How are They Treated?
Large myomas, those over 5-7 cm, should be removed laparoscopically using endoscopic methods. If the endometrial thickness is below 6-7 mm in the middle of the menstrual cycle during ultrasound examination, intrauterine adhesions may be present; this should be investigated with a uterine film or preferably hysteroscopy.
If there is a polycystic ovary appearance in the ovaries, the presence of insulin resistance should be investigated. Medication containing metformin and, if accompanied by obesity, weight loss under the supervision of a dietitian should be recommended; pregnancy should be postponed until the metabolic state improves.
Does Smoking Cause Miscarriages?
If there is heavy smoking—more than 10 cigarettes a day—it should be reduced and eventually abandoned. Folic acid supplementation should be started. Blood tests such as thyroid hormones, prolactin, hemogram, and AMH levels can be investigated. Low ovarian reserve may also play a role in miscarriages.
What are Recurrent Miscarriages? What Should Be Considered?
In a woman who has had two miscarriages, certain tests must be performed to investigate the cause. On the other hand, these tests can only reveal the cause in half of the cases. For young women who have had two or more miscarriages but have no problems detected in tests, the probability of becoming pregnant again is around 60-70%. Therefore, if no cause is identified, the probability of getting pregnant and having a healthy birth after recurrent pregnancy losses is as high as at least 60%. For this reason, it is important to keep morale high and maintain a positive approach.
When a woman who has had a previous miscarriage miscarries again, a genetic examination of the products of conception should be performed. Chromosomal anomalies can be detected in half of the miscarriages occurring in the first 12 weeks. When a genetic defect is identified, the probability of the subsequent pregnancy progressing well increases.
In couples who have had two previous miscarriages, chromosome tests (peripheral karyotype analysis) of both expectant parents must be performed. A uterine film should be reviewed. Coagulation tests for the woman should be requested.
In a woman who has experienced a miscarriage only once, no treatment or special follow-up is required. A woman with two or more miscarriages should be reassured that the probability of pregnancy and healthy birth is at least 60% and should be closely monitored when she becomes pregnant.
Couples with recurrent pregnancy losses should not switch directly to IVF treatments; first, an investigation into the cause should be conducted. IVF treatment may not be successful for every couple; in fact, IVF treatments themselves can further increase the risk of miscarriage. However, in women over the age of 39 with advanced maternal age, IVF treatments in which genetic examination of the embryo (PGT) is also performed should be applied.
