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

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.

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.

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 %).

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.