title: Conception, early pregnancy loss, and time to clinical pregnancy: a population-based prospective study.
abstract: OBJECTIVE
  To examine rates of conception and pregnancy loss and their relations with time to clinical pregnancy and reproductive outcomes.
  
  
  METHODS
  A prospective observational study.
  
  
  METHODS
  Population-based cohort in China.
  
  
  METHODS
  Five hundred eighteen healthy newly married women who intended to conceive. Upon stopping contraception, daily records of vaginal bleeding and daily first-morning urine specimens were obtained for < or =1 year or until a clinical pregnancy was achieved. Daily urinary hCG was assayed to detect early pregnancy loss (EPL).
  
  
  METHODS
  None.
  
  
  METHODS
  Conception, pregnancy loss, and time to clinical pregnancy.
  
  
  RESULTS
  The conception rate per cycle was 40% over the first 12 months. Of the 618 detectable conceptions, 49 (7.9%) ended in clinical spontaneous abortion, and 152 (24.6%) in EPL. Early pregnancy loss was detected in 14% of all the cycles without clinically recognized pregnancy, but the frequencies were lower among women with delayed time to clinical pregnancy. Early pregnancy loss in the preceding cycle was associated with increased odds of conception (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.8-3.9), clinical pregnancy (OR, 2.0; 95% CI, 1.3-3.0), and EPL (OR, 2.4; 95% CI, 1.4-4.2) but was not associated with spontaneous abortion, low birth weight, or preterm birth in the subsequent cycle.
  
  
  CONCLUSIONS
  We demonstrated substantial EPL in the non-clinically pregnant cycles and a positive relation between EPL and subsequent fertility.
authors.affiliation: Department of Pediatrics, Boston University School of Medicine and Boston Medical Center, Massachusetts, USA. xbwang@bu.edu
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Wang
authors.forename: Changzhong
authors.initials: C
authors.lastname: Chen
authors.forename: Lihua
authors.initials: L
authors.lastname: Wang
authors.forename: Dafang
authors.initials: D
authors.lastname: Chen
authors.forename: Wenwei
authors.initials: W
authors.lastname: Guang
authors.forename: Jonathan
authors.initials: J
authors.lastname: French
mesh_terms: D000022:Abortion, Spontaneous / Q000453:epidemiology*; D000328:Adult; D002681:China / Q000453:epidemiology; D006063:Chorionic Gonadotropin / Q000652:urine; D015331:Cohort Studies; D005260:Female; D005306:Fertilization; D005865:Gestational Age; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D011446:Prospective Studies; D013997:Time Factors
chemical_list: D006063:Chorionic Gonadotropin