Discrete survival model analysis of a couple’s smoking pattern and outcomes of assisted reproduction

Abstract

Background: Cigarette smoking has been associated with worse infertility treatment outcomes, yet some studies have found null or inconsistent results. Methods: We followed 225 couples who underwent 354 fresh non-donor assisted reproductive technology (ART) cycles between 2006 and 2014. Smoking history was self-reported at study entry. We evaluated the associations between smoking patterns and ART success using multivariable discrete time Cox proportional hazards models with six time periods: cycle initiation to egg retrieval, retrieval to fertilization, fertilization to embryo transfer (ET), ET to implantation, implantation to clinical pregnancy, and clinical pregnancy to live birth to estimate hazard ratios (HR) and 95% CIs. Time-dependent interactions between smoking intensity and ART time period were used to identify vulnerable periods.

Caffeine, alcohol, smoking, and reproductive outcomes among couples undergoing assisted reproductive technology treatments

“…For example, in a prospective cohort study of 225 couples undergoing ART treatment from 2006 to 2014 in Boston, Vanegas et al reported that smoking intensity among past and current female smokers was related to a higher risk of cycle failure before oocyte retrieval, even after accounting for duration of smoking and current smoking status. These results suggest that the effects of smoking on ovarian response to controlled ovarian stimulation may persist even after smoking cessation (64). This is similar to findings among women attempting to conceive without medical assistance which showed that higher cumulative exposure to active smoking was associated with reduced fecundability in both current and former regular smokers compared with never-smokers, and, among former smokers, time since quitting was not associated with fecundability (65).…”

“…To date, four studies (53,64,71,72) have evaluated male partner smoking and three (20,40,73,74) male partner intakes of alcohol and coffee in relation to infertility treatment outcomes with ART. Of the four studies evaluating male partner smoking, three (53,64,72) found no relation between male partner smoking status and ART outcomes, including one (72) where smoking status was determined with the use of urinary cotinine as an objective biomarker of exposure to cigarette smoke. Only the study by Klonoff-Cohen et al (71) found that male partner smoking status was related to lower probability of pregnancy and live birth.…”

“…Only the study by Klonoff-Cohen et al (71) found that male partner smoking status was related to lower probability of pregnancy and live birth. Nevertheless, one of these studies suggested a beneficial effect of smoking cessation of the male partner, whereby the risk of treatment failure decreased by 4% for each additional year before ART that the male partner had stopped smoking (64). The picture is murkier for studies evaluating the role of male partner intakes of alcohol and caffeine.…”

Lifestyle causes of male infertility

“…Moreover, male smoking could even influence the clinical pregnancy rate per intrauterine insemination (IUI) cycle [22] . Amongst former smokers, every additional year following the male partner’s smoking cessation reduced the risk of ART failure by 4%, particularly between clinical pregnancy and live birth [23] .…”

An update on the management of male infertility

“…37 Among former smokers, every additional year following smoking cessation of the male partner reduced the risk of treatment failure by 4%, particularly miscarriage. 38 Electronic cigarettes (e-cigarettes) typically contain propylene glycol (a tasteless, odourless, colourless alcohol used in antifreeze), vegetable glycerine, a variable amount of nicotine, food-grade flavouring and water to generate an aerosol/vapour. Their use is commonly termed 'vaping' and is generally viewed to be less harmful than conventional smoking.…”