From the Guidelines
Miscarriages in women are primarily caused by genetic, structural, endocrine, immune, thrombophilic, or unexplained factors, with fetal chromosomal defects accounting for up to 60% of cases. According to a recent study published in the British Journal of Sports Medicine in 2020 1, recurrent miscarriage, defined as the loss of three or more consecutive pregnancies before 24 weeks, affects 1% of women and may be attributed to various causes. The study highlights that fetal chromosomal defects and maternal congenital uterine abnormalities are non-modifiable and account for a significant proportion of miscarriages.
Some of the key factors that contribute to miscarriages include:
- Genetic issues, such as chromosomal abnormalities, which occur randomly during embryo development
- Maternal health conditions, such as uncontrolled diabetes, thyroid disorders, hormonal imbalances, and autoimmune diseases
- Structural problems with the uterus, such as fibroids, septum, or cervical insufficiency
- Advanced maternal age, with women over 40 having a significantly increased risk
- Lifestyle factors, such as smoking, excessive alcohol consumption, and drug use
- Certain infections, like listeria or toxoplasmosis
It is essential to note that miscarriages are rarely preventable and are not caused by normal activities, stress, or minor falls. The study 1 also suggests that prenatal exercise may benefit factors that increase the risk of miscarriage, such as insulin resistance and obesity, and improve general maternal health. Therefore, women with recurrent pregnancy loss should be encouraged to meet physical activity guidelines, as regular physical activity within guidelines is unlikely to increase the risk of a loss in this population.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Causes of Miscarriages
- Miscarriages can be caused by various factors, including abnormal chromosomes, endocrinological disorders, and uterine abnormalities 2
- Fetal chromosome abnormalities account for about 50% of first-trimester pregnancy losses, with most being numerical abnormalities (86%) and a low percentage caused by structural abnormalities (6%) or other genetic mechanisms 3
- Aneuploidy in the conceptus or fetus occurs in 5-10% of all pregnancies and is a common reproductive problem in humans, often resulting in early pregnancy loss 4
- Chromosomal aberrations in parents are a major pre-disposing factor and causative of abortion if carried over to the embryo, with a transmission rate in the embryo speculated to be about 50% 4
Genetic Factors
- Genetic factors play a significant role in miscarriages, with chromosomal abnormalities underlying the majority of cases 5
- Microsatellite genotyping and arrayCGH can detect submicroscopic chromosomal anomalies and gene dosage alterations, providing a comprehensive approach to analyzing chromosomal profiles of miscarriages 5
- A combination of cytogenetic karyotyping, microsatellite genotyping, and arrayCGH can identify chromosomal anomalies in approximately 61% of first-trimester miscarriages 5
- Genetic polymorphisms have also been found to be associated with recurrent miscarriages, highlighting the importance of genetic factors in miscarriage 4
Evaluation and Diagnosis
- Chromosomal analysis of the miscarriage offers an explanation in at least 50% of cases, making it a crucial step in evaluating the cause of miscarriage 6
- Conventional cytogenetic evaluation can only be done on fresh tissue, emphasizing the need for genetic testing at the time of miscarriage 6
- A multidisciplinary approach to miscarriage evaluation, including ultrasound, pathological examination, and genetic testing, is essential to understanding the cause and risk of recurrence 6