Preterm birth and its associated factors in coastal areas of eastern China: a multicenter retrospective study

Aim Preterm birth (PTB) is considered to be an important cause of neonatal mortality. However, most parts of China lack data or studies with large sample sizes to quantify the true burden of PTB. The current study aimed to determine the incidence of and factors associated with PTB in coastal areas of eastern China. Subject and methods This retrospective study included all eligible pregnant women who delivered in Lianyungang, Jiangsu Province, eastern China, between 1 July 2021 and 30 June 2022. Binary logistic regression was used to analyze the associated factors of PTB. Results A total of 29,807 pregnant women were included, and the incidence of PTB was found to be 5.1%. Multivariate regression analysis showed that pregnant women aged 18 years or younger (OR: 1.706, 95% CI: 1.207–2.409), who were 35 years or older (OR: 1.519, 95% CI: 1.312–1.760), or who had had a cesarean section delivery (OR: 1.542, 95% CI: 1.360–1.748), two or more perinatal births (OR: 14.557, 95% CI: 11.507–18.415), or four or more deliveries (OR: 1.614, 95% CI: 1.192–2.186) had a higher risk of PTB. Pregnant women with five or more prenatal visits (OR: 0.299, 95% CI: 0.241–0.372) had a lower risk of preterm delivery. In addition, pregnant women with hypertension (OR: 2.184, 95% CI: 1.666–2.863), preeclampsia (OR: 4.948, 95% CI: 3.014–8.124), gestational diabetes mellitus (OR: 1.610, 95% CI: 1.328–1.952), placenta previa (OR: 2.543, 95% CI: 1.836–3.523), or a history of PTB (OR: 9.028, 95% CI: 5.667–14.383) were more likely to have PTB. Conclusion The incidence of PTB was high and was affected by many factors. Early identification and management can reduce the incidence of PTB.