EVIDENCE THAT MALE SMOKING AFFECTS THE LIKELIHOOD OF A PREGNANCY FOLLOWING IVF TREATMENT - APPLICATION OF THE MODIFIED CUMULATIVE EMBRYO SCORE

Female cigarette smoking has been implicated as having a detrimental e ffect on in-vitro fertilization (IVF) outcomes mediated through: (i) a diminished ovarian reserve (DOR), and (ii) an elevated pregnancy loss . Research is sparse regarding the effect of male smoking. The objecti ve of this retrospective cohort study was to investigate the effect of male and female smoking on: (i) the collective quality of embryos sel ected for uterine transfer, and (ii) the likelihood of achieving an on going pregnancy at 12 Reeks. A total of 498 consecutive IVF treatment cycles were analysed. Female smokers were significantly younger (P < 0 .05) and achieved a better modified cumulative embryo score (mCES) (P < 0.05) than female non-smokers. Female age correlated inversely with the number of oocytes collected (r = -0.42, P < 0.01) and the number o f oocytes in turn was important in terms of predicting mCES. The decre asing number of oocytes aspirated with increasing age was of a signifi cantly stronger magnitude for female smokers than for female non-smoke rs (P < 0.05). Multiple logistic regression was used to determine whet her smoking affected the likelihood of achieving a 12-week pregnancy. The mCES, tubal infertility and male smoking were found to be signific ant. Male smoking interacted with male age (P = 0.0164), indicating fo r male smokers a decrease of 2.4% in the likelihood of achieving a 12- week pregnancy with every 1-year increase in age. This is the first st udy to show that male smoking has a deleterious effect on pregnancy ou tcome among IVF patients. Our study supports the increased risk of DOR but fails to support the elevated incidence of pregnancy loss among f emale smokers. A reduced pregnancy rate was associated with male smoki ng possibly through pre-zygotic genetic damage. The growing realizatio n of a paternal component of reproductive impairment suggests that stu dying the male is necessary.