Outcomes of 1503 cycles of modified natural cycle in vitro fertilization: a single-institution experience

PURPOSE: A retrospective cohort study was conducted in a single academic center to determine if modified natural cycle in vitro fertilization (mnIVF) is an acceptable treatment for the infertile couple. METHODS: Cycles performed between July 2005 and December 2011 were included. In our center's mnIVF protocol, a GnRH antagonist, gonadotrophin, as well as Indocid are given on a daily basis from detection of a dominant follicle until ovulation induction. The primary outcomes were clinical pregnancy rates (CPR) per cycle started and per embryo transfer (ET). Outcomes were stratified by female patient age (≤35 years and ≥36 years). They were further stratified in each age group by ovarian response status according to the 2011 Bologna criteria. RESULTS: A total of 1503 cycles of mnIVF, performed in 782 patients, were analyzed. CPRs were 13.7 % per started cycle and 32.5 % per ET. Stratification by ovarian response status (normal or poor) in each age group showed similar CPRs in patients ≤35 years (p = 0.373), and divergent CPRs per ET in patients ≥36 years old (26.26 vs 6.25 %). CONCLUSION: MnIVF is an acceptable treatment option for patients considering IVF, particularly for women ≤35 years old and for women ≥36 years old with normal ovarian response.