title: [Effects of maternal age on pregnancy: a retrospective cohort study].
abstract: OBJECTIVE
  To determine the pregnancy outcomes related with maternal age in China.
  
  
  METHODS
  A total of 110 450 cases were selected and divided into 6 age groups at intervals of 5 years. The clinical data were collected from 39 hospitals in mainland China. All deliveries were after 28 weeks of completed gestation in 2011. The unadjusted binary-logistic regression was employed for statistics.
  
  
  RESULTS
  The mean age of all pregnant women was 28 ± 5 at the time of delivery. The advanced age groups (35-39 yr and ≥ 40 yr) had higher risks than the 25-29 age group for pregestational diabetes [odds ratio (OR), 2.2 and 3.8], chronic hypertension (OR, 4.6 and 6.5), leiomyoma (OR, 4.2 and 5.8), gestational diabetes (OR, 2.6 and 3.5), preeclampsia (OR, 2.5 and 3.6), postpartum hemorrhage (OR, 1.5 and 1.7), premature delivery (OR, 1.8 and 2.4), placenta previa (OR, 2.7 and 4.0), placental abruption (OR, 1.4 and 2.5), cesarean delivery (OR, 2.1 and 2.5), macrosomia (OR, 1.2 and 1.2), low birth weight neonates (OR, 1.6 and 2.3) and perinatal mortality (OR, 1.6 and 3.7). The adolescent group had higher risks than the 25-29 age group for anemia (OR, 1.4), preeclampsia (OR, 1.6), preterm birth (OR, 2.1), low birth weight neonates (OR, 2.3) and perinatal mortality (OR, 3.6).
  
  
  CONCLUSIONS
  Maternal and neonatal risks are higher during both the adolescent and advanced maternal ages. And the age group of 20-30 years has the lowest risk for pregnancy and delivery.
authors.affiliation: Beijing Obstetrics & Gynecology Hospital, Capital Medical University, Beijing 100026, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Liu
authors.affiliation: Beijing Obstetrics & Gynecology Hospital, Capital Medical University, Beijing 100026, China.
authors.forename: Liying
authors.initials: L
authors.lastname: Zou
authors.affiliation: Beijing Obstetrics & Gynecology Hospital, Capital Medical University, Beijing 100026, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Beijing Obstetrics & Gynecology Hospital, Capital Medical University, Beijing 100026, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Ruan
authors.affiliation: Beijing Obstetrics & Gynecology Hospital, Capital Medical University, Beijing 100026, China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Beijing Obstetrics & Gynecology Hospital, Capital Medical University, Beijing 100026, China. Email: zhangwy9921@hotmail.com.
authors.forename: Weiyuan
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D001724:Birth Weight; D002585:Cesarean Section; D002681:China; D015331:Cohort Studies; D016640:Diabetes, Gestational; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D016015:Logistic Models; D008423:Maternal Age; D016017:Odds Ratio; D010923:Placenta Previa; D011225:Pre-Eclampsia; D011247:Pregnancy; D011248:Pregnancy Complications; D011256:Pregnancy Outcome; D047928:Premature Birth; D012189:Retrospective Studies