Effect of first birth interval length on preterm birth in Korean women

Abstract

The study aimed at examining risks on having preterm delivery depending on the length of interval between marriage and first birth by using raw data of reported singleton birth in Korea. Data for analysis were drawn from the 2010 Korean birth certification (235,333 singleton first births). Odds ratio and 95% confidence intervals were calculated from multinomial logistic regression analyses to describe the associations between length of first birth interval and risk of preterm birth. The mean length of first birth interval (LFBI) from marriage to first birth was 21.05 months. A prolonged LFBI was associated with increased risk of preterm birth. ‘J-shaped’ distribution of preterm birth incidence was observed in terms of LFBI, with that of 1 year birth interval being the lowest (3.5% in women aged under 34 years and 5.4% in women aged 35 and over). The odds ratio of preterm was 1.17 in women who had a LFBI of ＜1 year, 1.07 in women who had a LFBI of 2 years, and 1.57 women who had a LFBI of ≥ 6 years compared with women with a LFBI of one year. There were association between the risk of preterm birth and prolonged LFBI. © Rushing Water Publishers Ltd. 2018.