Cumulative pregnancy rates after minimal ovarian stimulation for in vitro fertilization

Abstract

In recent years there has been an increasing interest in minimal ovarian stimulation (MOS)protocols. Outcomes of in vitro fertilization (IVF) treatment often represent pregnancy rates per IVF cycle. But MOS cycles have a lower pregnancy rates per IVF cycle reported. Our aim of this study is to determine the viability of MOS protocols by looking at the cumulative pregnancy rates. Retrospective cohort study. We estimated cumulative pregnancy rates among infertile patients undergoing a clomiphene citrate based MOS or natural cycle IVF protocols between 2009 and 2012 in one private infertility centre. A total of 1700 patients who started their treatment in 2009 were enrolled in this study. Survival curves and Kaplan Meier methods to analyze clinical pregnancy rates (CPRs) stratified patients by their age(≤29,30-32,33-35,36-38,39-41,42-44,45≤) at the start of the treatment in a retrospective cohort with respect to the number of oocyte retrieval (OR) cycles. Among patients who were younger than 38 years of age, the corresponding pregnancy rates increase radically to 86.6% between cycle 1 and 5, increasing moderately to 96.4% between cycles 6 and 10. Among patients who were 39-41 years of age, the corresponding pregnancy rates increased moderately to 687% between cycles 1 and 10. Among patients who were over 42-44 years of age, the corresponding pregnancy rates also increased moderately to 45.1% between cycles 1 and 15. The cumulative pregnancy rates decreased with increasing age, and age stratified curves (≤38 vs. 39≤ years) were significantly different from one another (P<0.001). To our knowledge, this is the first report regarding cumulative pregnancy rates of only the MOS or natural cycle protocols. The results of our study demonstrate that it yields acceptable cumulative pregnancy rates in fertile patients up until their mid forties.