Preterm delivery (PTD) may predict the risk of long-term maternal complications. Little is known about the association between preterm delivery and maternal risk of chronic kidney disease (CKD).This study aimed to explore whether a history of preterm delivery is associated with the risk of maternal CKD.
In this population-based cohort study within the framework of the Tehran Lipid and Glucose Study (TLGS), a total of 3035 women with at least one delivery met our eligibility criteria. A time-dependent Cox proportional-hazards regression model was used to measure the hazard ratios (HRs) and 95% confidence intervals (CIs) for evaluating the association between history of preterm delivery and risk of CKD, adjusted for smoking, parity, age at first delivery, body mass index, educational level, preeclampsia, and gestational diabetes mellitus.
A total of 212 women with a history of at least one preterm delivery and 2823 women with term delivery were included. The median (interquartile range) follow-up in the preterm and term delivery groups was 16 (13.0-17.0) and 16 (14.0-17.0) years, respectively. The results of multivariate Cox regression model, adjusted for confounders, showed that the risk of CKD significantly increased by 46% in women with a history of preterm delivery. Moreover, according to the time-dependent Cox regression analysis, the risk of CKD in women with a history of preterm delivery was 2.68 (95% CI 1.02, 7.05, P = 0.04) fold higher than among those with no history of  preterm delivery.
Pregnancy if complicated by preterm delivery, may increase the risk of future maternal morbidities. Our findings suggest that a history of preterm delivery was associated with an increased maternal risk of CKD in the long term. Further longitudinal studies are needed to confirm our findings.