MedWire News: Exposure to secondhand smoke (SHS) is associated with fecundity and fetal loss in a dose-dependent manner, a study suggests.

Luke Peppone, from the University of Rochester in Minnesota, USA, and co-authors conducted an epidemiologic analysis of 4,804 nonsmoking women exposed to SHS and who reported at least one pregnancy attempt during 1982-1998.

In their study, four out of five women reported exposure to SHS during their lifetime, with half growing up in a home with smoking parents and nearly two-thirds exposed to SHS at the time of the survey.

More than 40 percent of all women had infertility lasting over a year or suffered miscarriages.

Women exposed as children to SHS were 1.27 times more likely have trouble becoming pregnant than those not exposed to SHS. Furthermore, women exposed to SHS as adults were 1.30 times more likely to experience pregnancy difficulties or fetal loss than women unexposed to SHS.

The researchers also found that exposure of 6 or more hours a day to SHS as an adult was related to the occurrence of both multiple fetal loss and reduced fecundity (odds ratios = 1.30 and 1.36, respectively), compared with no exposure.

“However, due to the prevalent nature of these data, the results must be interpreted with caution, and causality cannot be concluded,” cautions the team.

Journal abstract