Background:
Exposure to tobacco during pregnancy is an important risk factor for the low birth weight of the newborns. Arua district has a high prevalence of low birth weight (10.6%). Also, the prevalence of tobacco use in the district is the highest in Uganda being 33.7% and 4.7% among men and women respectively. We aimed at establishing the relationship between low birth weight and exposure to tobacco during pregnancy in Arua district.

Methods:
A facility based un-matched case control study. Cases were mothers that delivered newborns with birth weight less than 2500g during the study period whereas controls were mothers that delivered newborns with birth weight equal to or greater than 2500g during the study period. Two controls were selected per case. A semi-structured questionnaire was used to collect information. Stratified analysis was performed and Odds ratios (OR) used as the measure of association.

Results:
Exposure to tobacco during pregnancy was significantly associated with low birth weight (AOR= 2.21, 95%CI=1.31-3.74). The OR for the association between active tobacco use during pregnancy and low birth weight was 8.2 (95%CI=3.46-21.45). After adjusting for age of the mother, alcohol use during pregnancy and mother's nutritional status, the Adjusted Odds Ratios(AOR) were 11.95(95%CI=4.89-29.16), 6.69(95%CI=2.92-15.37), and 5.16(95%CI=2.24-11.86) respectively. Tobacco farming and processing was also found to be significantly associated with low birth weight (AOR= 2.98, 95%CI=1.54-5.79). Exposure to Second Hand Smoke at home was significantly associated with low birth weight (AOR=1.85, 95%CI=1.15-3.00).

Conclusions:
Exposure to tobacco during pregnancy was associated with low birth weight in Arua district. We recommend intensive health education of mothers by the Ministry of Health against exposure to tobacco during pregnancy.