What are the main causes or categories of recurrent pregnancy loss found in the meta-analysis?
Recurrent pregnancy loss (RPL) is defined as two or more consecutive pregnancy losses before 20 weeks. The meta-analysis of 105 studies involving 47,907 women aimed to determine how common RPL is and what proportion of cases fall into different etiological categories. The findings show that a large portion of RPL remains unexplained, but several known causes were identified.
What the research says
The meta-analysis pooled data from 105 studies and found that the most common category was idiopathic or unexplained RPL, accounting for 37% of cases (95% CI, 30–44%) 3. This means that in over a third of women with RPL, no clear cause is found after standard testing. The next most common category was acquired thrombophilia (blood clotting disorders), followed by uterine anomalies (structural problems of the uterus), endocrine disorders (hormonal issues), and other causes 3. The analysis also noted that only two studies provided population-based prevalence estimates, suggesting RPL affects about 1% of women, but this number is based on limited data 3. Other sources support these categories: uterine anatomic defects were found in 23.72% of women in one study 9, and endocrine disorders in 29.42% 9. Additionally, immune dysregulation, such as altered natural killer cell activity or Th1/Th2 imbalance, has been implicated in RPL 124. Chronic endometritis (inflammation of the uterine lining) is another recognized cause 8. Insulin resistance, measured by markers like TyG-BMI and METS-IR, has also been associated with increased odds of pregnancy loss in women with RPL 7.
What to ask your doctor
- What tests are available to identify the cause of my recurrent pregnancy loss?
- Could my RPL be related to a blood clotting disorder, and should I be tested for thrombophilia?
- Is there a role for immune system evaluation, such as natural killer cell testing or endometrial biopsy?
- Should I be screened for insulin resistance or other metabolic conditions?
- What are the treatment options if my RPL is classified as unexplained?
This question is drawn from common patient questions about OB/GYN & Women's Health and answered using cited medical research. We do not provide individualized advice.