September 22, 2010

Recurrent Pregnancy Loss Part I: Definition, Incidence, and Recurrence

The treatise to follow represents a compellation of my experience gleaned over almost 30 years since becoming a physician devoted to women’s reproductive health care; the first 20 years of which was spent in academic medicine performing both basic and clinically applied research in the areas of infertility and specifically, recurrent pregnancy loss (RPL). My comments and opinions are based on both my individual experience as a clinician, a clinical scientist, and as a student of the literature and work of many others in the field of reproduction.

When a baby is desired, success is expected immediately. However, the natural chance of becoming successfully pregnant per month of attempting pregnancy called fecundity, is only 1 in 5 or 20%. Pregnancy loss occurring before 20 weeks of gestation is called a miscarriage or by its medical term, spontaneous abortion and is the single most common complication of pregnancy, occurring in 8% of pregnancies in women under age 30 and over 26% of pregnancies in women over age 40. The chance of a miscarriage for women between the ages of 30 and 40 is approximately 15%. If a miscarriage has occurred the chance of a subsequent miscarriage in another pregnancy is not increased unless this was the second or more loss.

Recurrent Pregnancy Loss or RPL is defined as two or more pregnancy losses prior to 20 weeks of gestation. RPL occurs in approximately 1% of pregnancies which happens approximately 30,000 times annually in the United States alone. Studies from large populations of pregnant women indicate that if a woman has had two miscarriages then the chance of having her third loss is approximately 20%, if there have been three prior losses then the chance of a fourth is only 30%, and even if there have been four prior losses, the chance of a fifth spontaneous loss is 40%. So even with four prior losses the chance of having a successful pregnancy is as high as 60%.

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Joseph A. Hill, III, M.D.

Joseph A. Hill, III, M.D. Board-Certified in Reproductive Endocrinology and Infertility