Prolonged gonadotropin stimulation for assisted reproductive technology cycles is associated with decreased pregnancy rates for all women except for women with polycystic ovary syndrome.

PurposeTo determine if etiology of infertility modifies the relationship between the duration of ovarian stimulation and success during assisted reproductive technology (ART) cycles.MethodsA prospectively collected database was analyzed in an academic infertility practice. Eight hundred and twelve infertile women undergoing their initial fresh embryo, non-donor in vitro fertilization (IVF) or Intracytoplasmic Sperm Injection ICSI) cycle between January 1999 and December 2010 were evaluated. Clinical pregnancy was the main outcome measured.ResultsOut of 663 cycles resulting in oocyte retrieval, 299 produced a clinical pregnancy (45.1%). Women who achieved a clinical pregnancy had a significantly shorter stimulation length (11.9 vs. 12.1 days, p = 0.047). Polycystic ovary syndrome (PCOS) was the only etiology of infertility that was significantly associated with a higher chance for clinical pregnancy and was a significant confounder for the association of duration and success of treatment. Women with 13 days or longer of stimulation had a 34 % lower chance of clinical pregnancy as compared to those who had a shorter cycle (OR 0.66, 95% CI:0.46-0.95) after adjustment for age, ovarian reserve, number of oocytes retrieved, embryos transferred and PCOS diagnosis.ConclusionProlonged duration of stimulation is associated with decreased ART success for all couples, except for women with PCOS.