Effect of maternal lifestyle on low birth weight: a case-control study

Objective To investigate the association between maternal lifestyle and preterm low birth weight (PLBW) and term low birth weight (TLBW).Methods Using cluster sampling,14 hospitals in Jiangmen city were selected and 1964 pregnant women giving live birth to their singletons in these hospitals from August 2015 to May 2016 were surveyed with self-designed questionnaires.Two level logistic regression analysis was used in data analysis.Results The number of participants in the group of PLBW (giving the birth of a singleton with the birth weight of <2 500 grams at <37 gestational weeks),TLBW (with full-term singleton with birth weight of<2 500 grams) and controls (hospital- and birth time-matched and with live singleton of ≥2 500 grams birth weight) were 294,289 and 1 381,respectively.Among the pregnant women of the three groups,the prevalence of passive smoking were 36.39%,38.41%,and 33.09% and the prevalence of alcohol drinking were 2.72%,3.11%,and 1.59%,respectively.After adjusting for other confounders,doing physical exercise 1-3 times/week(adjusted odds ratioAOR=0.58,95% confidence intervalCI=0.40-0.86) and more than 4 times/week (AOR=0.54,95%CI=0.37-0.78) during pregnancy were protective factors of PLBW compared with not doing exercise during pregnancy;using electronic equipment like mobile phone,computer,or television 1-2 hours/day (AOR=0.61,95%CI=0.40-0.93),3-4 hours/day (AOR=0.55,95%CI=0.35-0.86),and more than 4 hours/day (AOR=0.57,95%CI=0.37-0.89) showed protective effect on TLBW when compared with using the equipments less than 1 hour/day.Passive smoking during pregnancy increased the risk of TLBW (AOR=1.36,95%CI=1.02-1.81).Conclusion Maternal lifestyle during pregnancy may play a role in the occurrence of infant low birth weight and the role is different for PLBW and TLBW.The results suggest targeted interventions are needed to decrease the prevalence of infant low birth weight.