title: Association of assisted reproductive technology with adverse pregnancy outcomes.
abstract: BACKGROUND
  More and more infertile patients have accepted the assisted reproductive technique (ART) therapy. Concerns have been raised over an increased risk of adverse maternal outcomes in ART populations as compared with natural conception (NC).
  
  
  OBJECTIVE
  The aim was to improve the ART in clinicial work and to reduce the incidence of pregnancy complications in ART group according to analyzing the reasons of high incidence of pregnancy complications in ART group, comparing the incidence of pregnancy complications in different controlled ovarian hyperstimulation (COH) programs and evaluating the effects of ART which attribute to adverse pregnancy outcomes.
  
  
  METHODS
  In this prospective population-based cohort study,3216 pregnant women with gestational age ≤12 weeks, regular antenatal examination,and ultrasound identification of intrauterine pregnancy were enrolled from January 2010 to June 2013. According to having ART history, the participantswere divided into two groups: ART group (contains fresh embryo transfer group or frozen-thawed embryo transfer group) and NC group. We compared the incidence of pregnancy complications between different groups and evaluated the factors which could affect the occurrence of these complications.
  
  
  RESULTS
  When compared to NC group, significantly increased rates of gestational diabetes mellitus (GDM) (p<0.01), preeclampsia (PE) (p<0.01) and intrahepatic cholestasis of pregnancy (ICP) (p˂0.01) were observed in ART group. There was no significant difference in the incidence of birth defect between the two groups (p=0.07). Multiple pregnancies and Gonadotropin (Gn) were risk factors in GDM, PE, and ICP. The exogenous progesterone treatment had no effect on GDM, PE or ICP.
  
  
  CONCLUSIONS
  ART increases the risk of adverse maternal complications such as GDM, PE and ICP. The dosages of Gn should be reduced to an extent and the number of embryo implantation should be controlled. Exogenous progesterone treatment is safe.
authors.affiliation: Department of Obstetrics and Gynecology , T he Second Xiangya Hospital, Central South University, Changsha, Hunan Province, People ' s Republic of China.
authors.forename: Zhang
authors.initials: Z
authors.lastname: Jie
authors.affiliation: Department of Obstetrics and Gynecology , T he Second Xiangya Hospital, Central South University, Changsha, Hunan Province, People ' s Republic of China.
authors.forename: Ding
authors.initials: D
authors.lastname: Yiling
authors.affiliation: Department of Obstetrics and Gynecology , T he Second Xiangya Hospital, Central South University, Changsha, Hunan Province, People ' s Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Ling
keywords: Assisted reproductive technique; Infertility; Pregnancy complications