Epidemiological factors influencing IVF outcome: Evidence from the Yale IVF program

Age, BMI, lifestyle, menstrual status and obstetric history can modulate the endocrine system and, therefore, have been hypothesised to play a role in in-vitro fertilisation (IVF) outcome. We designed a retrospective study, set in a medical school hospital. We evaluated the medical files of 297 infertile women who underwent laparoscopy and consecutive IVF-ET treatment in the Yale IVF unit between 1996 and 2002. The study group consisted of 151 women who conceived after IVF-ET and the control group of 146 women who underwent 288 IVF-ET cycles without pregnancy. The main outcome measure was the impact of epidemiological factors on the IVF outcome. There was no association between IVF outcome and race, BMI, age at menarche, length of cycle, duration and amount of flow, menstrual symptoms, other medical problems, medical history of allergies, and family history of endometriosis and cancer. We found that the degree of smoking and alcohol use was not a factor when comparing women with and without pregnancy after IVF (34.5% vs 29.5%, and 33.7% vs 27%, respectively). The rate of duration of infertility tended to be lower in pregnant women (35.9+/-23.4 months) vs (42.3+/-30.2) non-pregnant women. As expected, we also confirmed the inverse association between the age of women and IVF outcome. Overall, body attributes, lifestyle, family history, menstrual and reproductive factors were not related to IVF-ET outcome.