title: Factors affecting pregnancy outcome resulting from assisted reproductive technology (ART).
abstract: OBJECTIVE
  A retrospective, observational study of pregnancy outcome was performed on variables maintained in an ART database to determine factors that might affect miscarriage rate in pregnancies resulting from assisted reproduction technologies (ART).
  
  
  METHODS
  Previously infertile couples, where conception was achieved after ART, were included. Seven hundred and ninety-four consecutive clinical pregnancies, diagnosed by ultrasound documentation of the gestation sac in the first trimester were divided into 2 groups: 'miscarriage' and 'term birth'. Differences between the groups were analysed using crosstable regression analyses or t-test in second yearly cohorts.
  
  
  RESULTS
  A statistically significant positive relationship was seen between age and spontaneous abortion rate (p = 0.008) with a major increase after the age of 38 years. There was no significant difference in the mean number of oocytes retrieved between groups (p = 0.17). While there was a significant negative correlation between maternal age and the total number of oocytes collected (p < 0.001), there was no statistical difference between those women who miscarried or delivered a live infant. No relationships were found with any other variables analysed.
  
  
  CONCLUSIONS
  Maternal age is probably the most important factor in pregnancy outcome in ART. This survey could not determine any other variables as being major prognostic determinant for miscarriage once pregnancy was attained.
authors.affiliation: Department of Obstetrics and Gynecology, First Affiliated Hospital of Sun Yat-sen University of Medical Science, China.
authors.forename: C
authors.initials: C
authors.lastname: Zhou
authors.forename: D C
authors.initials: DC
authors.lastname: Knight
authors.forename: J P
authors.initials: JP
authors.lastname: Tyler
authors.forename: G L
authors.initials: GL
authors.lastname: Driscoll
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D008423:Maternal Age; D008875:Middle Aged; D011247:Pregnancy; D011256:Pregnancy Outcome; D012099:Reproductive Techniques; D012189:Retrospective Studies; D012307:Risk Factors