Role of passive tobacco smoking in the development of IUGR baby

Abstract Objective: To see the role of passive tobacco smoking in the development of IUGR baby. Study design: A case control study was carried out during the period of 1st July 2007 to 30th June 2009 in the Department of Paediatrics and Department of Obstetrics and Gynaecology, MAG Osmani Medical College Hospital, Sylhet. Methodology: A total of 75 newborn IUGR infants age <24 hrs of both non smoker mothers and those who do not intake smokeless tobacco during intrauterine period were taken as cases by systematic random sampling after meeting inclusion and exclusion criteria and by using formula of: Sample size (N)=Z-pq/d². A 75 Non-IUGR term infants of less than 24 hour’s age having history of mild parinatal asphyxia (APGAR scrore >8) were selected as control. Immediately after admission detailed history of the newborn baby and mother were taken. Each baby was weighted in gram using NNC bar scale and thorough physical examination was done. IUGR infants were diagnosed by plotting the birth weight on the intrauterine Growth Chart. Gestational age of the baby was determined from the 1st day of last regular menstruation and also by New Ballard Scoring system. All the STORCH infected, chromosomally abnormal (syndrome baby), preterm babies, were excluded from the study. Mothers who were suffering from HTN. CRF, DM and those with Hb <10 gm, BMI <17 were excluded from study. Results: Baseline characteristics of cases and controls were comparable. Exposure to passive tobacco smoking during pregnancy is significantly (P<.001) associated with IUGR baby and carries a risk of having IUGR baby about 5.5 times more than non-smoking (exposed) mothers (Odd ratio is 5.5). Exposure rate in study case is 74.7% and in control is 34.7%. Passive smoking exposure in antenatal period reducing birth weight of baby on average is 82 grams. Duration of exposed smoking in pregnancy on average of 1.8 hours and has significant association (P<.001) in the development of IUGR baby. Smoking in bedroom has significant association (P<.001) in the development of IUGR baby. Conclusion: It can be concluded that mothers who were exposed to passive tobacco smoking of an average of 1.8 hours per day have 5.5 times increase risk of having IUGR baby than non-exposed mothers.