Prognosis for live birth in women with recurrent miscarriage: what is the best measure of success?

OBJECTIVE To establish a method of estimating the proportion of women with a subsequent live birth after a well-defined time period in an open cohort of women referred to a tertiary recurrent miscarriage clinic. METHODS We performed a descriptive cohort study with register-based follow-up at a tertiary center for investigation and treatment of recurrent miscarriage in Denmark. All women with primary or secondary recurrent miscarriage referred to the clinic from 1986 to 2008 were included in the study (n=987). Main outcome measures were age-specific and miscarriage-specific proportions of women with a live birth after the first consultation and similar hazard ratios compared with the prognosis in women aged 30-34 years with three miscarriages before the first consultation. RESULTS Five years after the first consultation, 66.7% (95% confidence interval [CI] 63.7-69.7) had achieved a live birth, increasing to 71.1% (95% CI 68.0-74.2) 15 years after the first consultation. There was a significantly decreased chance of at least one subsequent live birth with increasing maternal age (log-rank P<.01) and increasing number of miscarriages (log-rank P<.01) at first consultation. CONCLUSION Approximately two thirds of women with recurrent miscarriage referred to a tertiary center succeed in having at least one live birth within 5 years after their first consultation. Our study allows for a descriptive overview of the course of live birth outcome in women with recurrent miscarriage, but not for evaluation of the effect of treatment.