Low birth weight and prenatal exposure to indoor pollution from tobacco smoke and wood fuel smoke: a matched case-control study in Gaza Strip.

Maternal exposure to environmental tobacco smoke (ETS) is a major health hazard as it contains lower doses of the toxins that smokers' inhale. Prenatal exposure to wood fuel smoke has been linked to delivering low birth weight (LBW) infants. The study aims to assess the association between prenatal exposure to ETS and wood fuel smoke and LBW. A case-control study in ratio 1:1 was conducted in two hospitals with obstetric services in Gaza Strip. Subjects were selected during May-June and July-August 2007 from attenders of Mbarak Hospital and Shifa Medical Centre, respectively. 184 (41.2%), and 79 (17.7%) out of 446 participants were exposed to environmental tobacco smoke and wood fuel smoke, respectively. Adjusted maternal exposure to ETS (especially the number of cigarettes smoked, water pipe and wood fuel smoke) was associated with LBW infants. Cigarette smoke exhibits an independent dose-response risk of LBW after adjusting for confounders. Prenatal exposure to cigarette smoke indoors is related to a reduction in birth weight of infants of -237 g (95% CI: -415, -58) for pregnant women exposed to 1-20 cigarettes per day and -391 g (95% CI: -642, -140) for exposure to more than 20 cigarettes per day. Exposure to wood fuel smoke exhibits a reduction of infants' adjusted mean birth weight by -186 g (95% CI: -354, -19). Prenatal exposure to passive smoking and wood fuel smoke are independently associated with LBW. Both these factors are modifiable exposures that could possibly lead to a reduction of delivering LBW infants.