Abstract: Objective:To study the risk factors for low birth weight infants(LBWI) during pregnancy and pregnancy periods in Dalian.
Methods:A total of 402 cases of LBWI, born in Dalian from Apr. 2012 to Oct. 2019, were divided into 3 groups according to their birth weights:8 cases in ELBWI group (≤1 000 g), 70 cases in VLBWI group(1 001-1 500 g), and 324 cases in LBWI group (1 501-2 500 g). IMOCH infant high-risk factor scoring questionnaire was adopted to systematically collect the clinical data for retrospective study.
Results:The pregnancy risk factors in this study included: a history of bad pregnancy (18.40%) and age of pregnancy <18 or ≥35 (13.93%). The risk factors during pregnancy were as follows (in the turn of exposure)：premature rupture of membrane （30.60%），multiple gestation (≥2 fetuses)(29.35%), pregnancy-induced hypertension syndrome or epilepsy（23.88%）. With time going, the occurrence of such risk factors as history of bad pregnancy, maternal age of pregnancy<18 or ≥(35, and threatened abortion reduced, while the occurrence of multiple pregnancy(≥2 fetuses) increased. Regression analysis suggested that the occurrence of LBWI was related to history of bad pregnancy, age of pregnancy <18 or ≥35, premature rupture of membrane, pregnancyinduced hypertension syndrome or epilepsy, pregnancy induced diabetes and abnormal umbilical cord, and there was statistical difference among the groups (P<0.05).
Conclusion:The occurrence of low birth weight infants is affected by various factors before pregnancy and perinatal period, and various complications can occur. The incidence of LBWI can be reduced by controlling high-risk factors as early as possible and strengthening health care during perinatal period.

Key words: Low birth weight infant, Risk factor, Infant, newborn