Association of low birth weight with environmental tobacco smoke (ETS) exposure among pregnant women.

Abstract

Objectives: To determine the association between low birth weight babies and environmental tobacco smoke (ETS) exposure during pregnancy and the factors related to it. Study Design: Case Control study Setting: Obstetrical and Gynecological Units of a Sir Ganga Ram Hospital, Lahore. Period: March 2016 to August 2017. Material & Methods: Babies born to mothers’ aged between 20 to 35 years in all four Obstetrical and Gynecological units of a Sir Ganga Ram hospital, Lahore, were included. 150 low birth weight babies (LBW) born at term, fulfilling the exclusion and inclusion criteria were taken as cases and 150 normal weight babies born on same day were taken as controls. Mothers were interviewed on a semi structured and pretested questionnaire covering all variables using non- probability purposive sampling technique and the data was analyzed on SPSS Version 20.0. The difference of means was tested using independent t-test whereas difference of proportions was analyzed by using Pearson Chi -Square test. Odds Ratio of >2 was taken as significant. P value <0.05 was considered statistically significant. In order to adjust the effect of confounder data was stratified. Results: 110/150(73.3%) cases and 48/150(32%) controls were exposed to ETS with odds of low birth weight being 5.84 times higher among exposed mothers. Odds of having low birth weight was 3.55 times for ETS exposure at home than those not having home exposure. Ninety Six cases (64%) and 70(46.7%) controls had no knowledge about passive smoking. Only one third of all respondents had knowledge about Second Hand Smoke(SHS) while 110 exposed to ETS, only 09 had adequate knowledge about passive smoking with a significant difference in the knowledge among mothers of the cases and controls (p value 0.004, T score -2889). Conclusion: Mothers exposed to ETS had 5.84 odds of having LBW babies than unexposed, endorsing the association between the two particular when at home. Illiteracy, illiterate smoker husband and poor knowledge of mother about SHS and its hazards further escalated the situation. More researches are, therefore, required to evaluate the effects of passive smoking exposure in a low income country like Pakistan and steps should be taken to avoid it especially during pregnancy.