Recurrent miscarriage, also known as recurrent pregnancy loss (RPL), is defined as three consecutive spontaneous miscarriages before the 20th week of pregnancy. The key factor is that the losses must be back-to-back, meaning that if a woman experiences a miscarriage, then has a successful pregnancy, followed by two more miscarriages, this would not meet the strict definition of recurrent miscarriage.  

Additionally, for a miscarriage to be counted in this diagnosis, the pregnancy must have been confirmed by ultrasound. Biochemical pregnancies, where only a positive β-hCG test is detected without a visible embryo on ultrasound, are not included in this classification.  

Recurrent miscarriage affects about 1% of women and can have multiple underlying causes, including genetic, anatomical, immunological, or hormonal factors. If a woman experiences repeated pregnancy losses, seeking medical evaluation can help identify potential causes and guide personalized treatment strategies.