title: Maternal tea consumption and the risk of preterm delivery in urban China: a birth cohort study.
abstract: Studies investigating the relationship between maternal tea drinking and risk of preterm birth have reached inconsistent results.
  
  
  
  The present study analyzed data from a birth cohort study including 10,179 women who delivered a singleton live birth were conducted in Lanzhou, China between 2010 and 2012.
  
  
  
  Drinking tea (OR = 1.36, 95 % CI: 1.09-1.69), and specifically green (OR = 1.42, 95 % CI: 1.08-1.85) or scented tea (OR = 1.61, 95 % CI: 1.04-2.50), was associated with an increased risk of preterm birth. Drinking tea was associated with both moderate preterm (OR = 1.41, 95 % CI: 1.12-1.79) and spontaneous preterm birth (OR = 1.41, 95 % CI: 1.09-1.83). Risk of preterm birth increased with decreasing age of starting tea drinking (<20 years, OR = 1.60, 95 % CI: 1.17-2.20) and increasing duration (p for trend < 0.01). The relationship between tea drinking and preterm birth is modified by both maternal age (p < 0.05) and gestational weight gain (p < 0.05).
  
  
  
  Despite conflicting findings in the previous literature, we saw a significant association with maternal tea drinking and risk of preterm birth in our cohort. More studies are needed both to confirm this finding and to elucidate the mechanism behind this association.
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.affiliation: Yale University, School of Public Health, 60 College Street LEPH 440, New haven, CT, 06520, USA.
authors.forename: Catherine
authors.initials: C
authors.lastname: Lerro
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Qiu
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Weitao
authors.initials: W
authors.lastname: Qiu
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Xiaochun
authors.initials: X
authors.lastname: He
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Cui
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Lv
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Ruifeng
authors.initials: R
authors.lastname: Xu
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China.
authors.forename: Xiaoying
authors.initials: X
authors.lastname: Xu
authors.affiliation: Yale University, School of Public Health, 60 College Street LEPH 440, New haven, CT, 06520, USA.
authors.forename: Huang
authors.initials: H
authors.lastname: Huang
authors.affiliation: Gansu Provincial Maternity and Child Care Hospital, 143 North Road Qilihe District, Lanzhou, Gansu Province, 730050, China. 2305470816@qq.com.
authors.forename: Qing
authors.initials: Q
authors.lastname: Liu
authors.affiliation: Yale University, School of Public Health, 60 College Street LEPH 440, New haven, CT, 06520, USA. yawei.zhang@yale.edu.
authors.forename: Yawei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D044466:Asian People; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D039382:Maternal Nutritional Physiological Phenomena; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology / Q000209:etiology*; D012307:Risk Factors; D012959:Socioeconomic Factors; D013662:Tea / Q000009:adverse effects*; D014505:Urban Population / Q000706:statistics & numerical data*; D015430:Weight Gain; D055815:Young Adult
chemical_list: D013662:Tea
keywords: Birth cohort; China; Preterm; Tea