Female and male lifestyle habits and IVF: what is known and unknown.

There is no greater tribute to the importance and efficacy of IVF than the fact that >1 x 10(6) babies have been born to infertile couples since its clinical introduction in 1978. Despite enormous advances regarding the technical aspects of the IVF procedure, the parents' contribution has virtually been ignored when considering aspects that influence success rates. This systematic review focuses on the effects of female and male lifestyle habits (specifically: smoking, alcohol and caffeine use, and psychological stress) on the reproductive endpoints of IVF (i.e. oocyte aspiration, fertilization, embryo transfer, achievement of a pregnancy, live birth delivery, and perinatal outcomes, e.g. low birthweight, multiple gestations). What is currently known in the field of lifestyle habits and IVF? There is compelling evidence that smoking has a negative influence on IVF outcomes, whereas for stress, the evidence is suggestive but insufficient due to the heterogeneity of studies. The evidence for the effects of alcohol and caffeine on IVF is inadequate, and therefore unknown, due to the scarcity of studies.