Prevalence Of Low Birth Weight And Its Determinants In Tianjin,China

Background Low birth weight(LBW)is defined as an infant born with a birth weight of less than 2500 g.LBW is an important risk factor that influences perinatal,neonatal and infants' health,which is considered to be a critical social-demographic problem.In 2012,WHO estimated that global LBW annual incidence ranged from 15% to 20%(about 20 million LBW infants each year).However,the prevalence of LBW and its determinants,and more importantly,how to prevent LBW neonates remain largely unknown.It is essential to accurately estimate the prevalence of LBW and its determinants to identify pregnant women at high risk,so that further intervention studies could be carried out to decrease the rate of LBW in Tianjin,China.Objective To investigate the prevalence of LBW neonates and its' determinants in Tianjin,China.Methods Data on neonatal information(from January 1 to December 31 in 2013)were retrieved from Tianjin Maternal and Child Health Care Management System.Descriptive statistics were performed to analyze the distribution of LBW and related factors.Univariable and multivariable binary logistic regression analyses were performed to explore risk factors for LBW.Results During the study period,there were a total of 110,131 live births registered in maternal and child care institutions in the 16 districts of Tianjin,which accounted for 99.5% of the total registered neonates.The mean neonatal birth weight in Tianjin was 3344 g(SD: 495 g),and the median birth weight was 3355 g(IQR: 3050-3650g).LBW accounted for 4.0%(95%CI:3.9%-4.1%)of the live births,among which 3.6% birth weight between 1500 g and 2500 g,0.4% between 1500 g and 1000 g,and 0.1% birth weight < 1000 g.The prevalence of LBW was significantly different by location(i.e.,districts,P <0.001)and many other key varibales.For instance,the LBW prevalence was higher in female neonates than in male neonates(4.3% vs.3.7%,P<0.001);higher in the town than in the rural areas(4.4% vs.3.5%,P<0.001);higher in the urban than in the inner or outer suburbs(5.1% vs.3.4% or 3.7%,all P<0.001);higher in preterm births(gestational age < 37 weeks)than in term births(37-41 gestational weeks)and post term births(?42 gestational weeks)(48.3% vs.1.4% or 0.8%,all P<0.001);higher in multiple pregnancies than in singleton pregnancies(43.8% in twins and 100% in triplets vs.3.0% in single births,P<0.001);higher in neonates in poor health condition than in moderate or good health condition(86.6% vs.8.0% or 3.5%,all P<0.001),higher in neonates whose mother's number of pregnancy =1 than multiple pregnancies(4.2% vs 3.8% in twice and 4.0% in number of pregnancy ?3,P=0.02),highest in neonates whose mother's delivery time ?3 then delivery time =1,and deliveries time=2 were 4.7%,4.2% and 3.5%,respectively(all P<0.001);higher in neonates whose mother's pregnancy weight gain <10 kg than weight gain?10kg(5.8% vs.2.8% in 10-19 kg weight gain or 2.7% in more than 20 kg,all P<0.001);higher in neonates born to mother with positive syphilis test results than with negative results(9.9% vs.4.0%,P<0.001),higher in neonates whose mother were at high risk shown by the prenatal screening than at low risk(6.6% vs.3.4%,P<0.001).After adjusting for other covariables,female gender of neonates(OR:1.51,95%CI:1.35-1.68),preterm birth(OR:39.34,95%CI: 35.13-44.05),maternal weight gain during pregnancy <10 kg(OR:1.55,95%CI: 1.35-1.79),multiplets(OR:11.32,95%CI: 9.51-13.48),moderate health condition(OR:1.97,95%CI:1.54-2.51)or poor health condiction of neonates(OR:97.64,95%CI: 64.24-148.41),positive syphilis test result(OR:3.06,95%CI: 1.42-6.57),and high risk pregnancy shown by the prenatal screening(OR:1.63,95%CI:1.33-2.00)were risk factors of LBW.In contrary,suburban residence of the mother(inner suburb OR: 0.73-0.82,95%CI: 0.62-0.99 and outer suburb OR: 0.82,95%CI: 0.69-0.99),number of pregnancy?2(OR:0.84,95%CI: 0.72-0.98)and number of delivery?2(OR:0.66,95%CI:0.54-0.79)were protective factors for LBW.Conclusion The prevalence of LBW was up to 4.0% in 2013 in Tianjin,China.Female,preterm birth,maternal weight gain during pregnancy <10 kg,multiplets,neonate in moderate or poor health condition,positive syphilis RPR test result,and high risk pregnancy as shown by prenatal screening were risk factors for LBW.On the other hand,suburban residence of mother and gravidity or parity ?2 were protective factors for LBW.Randomized controlled trials are needed to ascertain that balanced diet and maintenance of a reasonable weight gain can reduce the occurrence of LBW.