January 21, 2026
Top Causes of Miscarriage & Risk Factors Explained
One in four pregnancies ends in miscarriage, often due to chromosomal abnormalities, hormonal imbalances, or anatomical issues. Hormonal conditions like PCOS increase miscarriage risk by 2-3 times, while a detected fetal heartbeat reduces second-trimester loss risk to 7%. Most single miscarriages are random but recurrent losses may require fertility evaluations.
Key Takeaways
Chromosomal Abnormalities: Leading Cause of Early Miscarriage
Approximately 50-60% of first-trimester miscarriages stem from chromosomal abnormalities in the embryo, often random and unrelated to parental genetics. Genetic screening like preimplantation genetic testing (PGT) can identify viable embryos during IVF.
PCOS and Increased Miscarriage Risk: Management Strategies
Polycystic ovary syndrome (PCOS) raises miscarriage rates by 2-3 times due to insulin resistance and hormonal dysregulation. Fertility specialists recommend metformin or Myo-inositol supplements to regulate ovulation and reduce miscarriage risk by 40-50%.
Single Miscarriage Doesn’t Guarantee Recurrence: Key Factors
Having one miscarriage doesn’t increase future risk unless anatomical issues (e.g., uterine fibroids) or immunologic disorders (e.g., antiphospholipid syndrome) are present. Most women with one miscarriage have a 70-80% chance of successful pregnancy in subsequent attempts.
Miscarriage Risk Drops to 7% After Heartbeat Detection
Once a fetal heartbeat is confirmed via ultrasound (typically 6-8 weeks gestation), the risk of second-trimester miscarriage declines to 7%. This drops further to 1% if an embryo is seen with a gestational sac and yolk sac at 5 weeks.
Post-Miscarriage Fertility Workup for Recurrent Pregnancy Loss
After two or more consecutive miscarriages, fertility specialists recommend a comprehensive workup including hysterosalpingogram (HSG) for anatomical issues, thyroid function tests, and karyotyping for chromosomal abnormalities in both partners. 60% of women with two miscarriages conceive successfully after treatment.
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