Naho Morisaki1, Kohei Ogawa1,2,3, Kevin Y Urayama1,4, Haruhiko Sago2,3, Shoji Sato5, Shigeru Saito6. 1. Department of Social Medicine. 2. Center of Maternal-Fetal, Neonatal and Reproductive Medicine, National Center for Child Health and Development, Tokyo, Japan. 3. Collaborative Departments of Advanced Pediatric Medicine, Tohoku University, Miyagi, Japan. 4. Graduate School of Public Health, St Luke's International University, Tokyo, Japan. 5. Perinatal Center, Oita Prefectural Hospital, Oita, Japan. 6. Department of Obstetrics and Gynecology, University of Toyama School of Medicine, Toyama, Japan.
Abstract
Background: Maternal short stature has been observed to increase the risk of preterm birth; however, the aetiology behind this phenomenon is unknown. We investigated whether preeclampsia, an obstetric complication that often leads to preterm delivery and is reported to have an inverse association with women's height, mediates this association. Methods: We studied 218 412 women with no underlying diseases before pregnancy, who delivered singletons from 2005 to 2011 and were included in the Japan Society of Obstetrics and Gynecology perinatal database, which is a national multi-centre-based delivery database among tertiary hospitals. We assessed the risk of preterm delivery in relation to height using multivariate analysis, and how the association was mediated by risk of preeclampsia using mediation analysis. Results: Each 5-cm decrement in height was associated with significantly higher risk of preterm delivery [relative risk 1.20; 95% confidence interval (CI): 1.13, 1.27] and shorter gestational age (-0.30; 95% CI: -0.44, -0.16 weeks). Mediation analysis showed that the effect of shorter height on increased risk of preterm delivery, due to an indirect effect mediated through increased risk of preeclampsia, was substantial for shorter gestational age (48%), as well as risk of preterm delivery (28%). When examining the three subtypes of preterm delivery separately, mediated effect was largest for provider-initiated preterm delivery without premature rupture of membranes (PROM) (34%), compared with spontaneous preterm delivery without PROM (17%) or preterm delivery with PROM (0%). Conclusions: Preeclampsia partially mediates the association between maternal short stature and preterm delivery.
Background: Maternal short stature has been observed to increase the risk of preterm birth; however, the aetiology behind this phenomenon is unknown. We investigated whether preeclampsia, an obstetric complication that often leads to preterm delivery and is reported to have an inverse association with women's height, mediates this association. Methods: We studied 218 412 women with no underlying diseases before pregnancy, who delivered singletons from 2005 to 2011 and were included in the Japan Society of Obstetrics and Gynecology perinatal database, which is a national multi-centre-based delivery database among tertiary hospitals. We assessed the risk of preterm delivery in relation to height using multivariate analysis, and how the association was mediated by risk of preeclampsia using mediation analysis. Results: Each 5-cm decrement in height was associated with significantly higher risk of preterm delivery [relative risk 1.20; 95% confidence interval (CI): 1.13, 1.27] and shorter gestational age (-0.30; 95% CI: -0.44, -0.16 weeks). Mediation analysis showed that the effect of shorter height on increased risk of preterm delivery, due to an indirect effect mediated through increased risk of preeclampsia, was substantial for shorter gestational age (48%), as well as risk of preterm delivery (28%). When examining the three subtypes of preterm delivery separately, mediated effect was largest for provider-initiated preterm delivery without premature rupture of membranes (PROM) (34%), compared with spontaneous preterm delivery without PROM (17%) or preterm delivery with PROM (0%). Conclusions: Preeclampsia partially mediates the association between maternal short stature and preterm delivery.
Authors: Chang Chen; Jin Wen Zhang; Hong Wei Xia; Hui Xin Zhang; Ana Pilar Betran; Lin Zhang; Xiao Lin Hua; Li Ping Feng; Dan Chen; Kang Sun; Chun Ming Guo; Hong Bo Qi; Tao Duan; Jun Zhang Journal: Am J Public Health Date: 2019-09-19 Impact factor: 9.308