title: Increased adverse pregnancy outcomes with unreliable last menstruation.
abstract: OBJECTIVE
  To estimate the risk of adverse outcomes in women whose first day of the last menstrual period (LMP) was unreliable.
  
  
  METHODS
  Among 20,244 singleton pregnancies with measurements of biparietal diameter between 12 and 22 weeks' gestation, LMP was registered as unreliable in 3775 (18.6%) and reliable in 16,469 (81.4%). Adverse outcomes were defined as spontaneous or missed abortions after 12 weeks' gestation, stillbirth or postnatal death within 1 year, preterm birth, birth weight less than 2500 g, and low birth weight (LBW) for gestation (lower than 22% below sex-specific expected weight). Logistic regression analysis and Kaplan-Meier survival analysis were used to analyze the risk of adverse outcomes.
  
  
  RESULTS
  The risk of death was doubled in pregnant women with unreliable LMPs compared with those with reliable LMPs (odds ratio [OR] 2.0; 95% confidence interval [CI] 1.5, 2.6). This risk was highest with respect to stillbirth (OR 2.7; 95% CI 1.7, 4.3). The risks of preterm birth, LBW, and LBW for gestation were also significantly increased (ORs 1.5, 1.4, and 1.2; 95% CIs 1.3, 1.7; 1.2, 1.6; and 1. 0, 1.4, respectively).
  
  
  CONCLUSIONS
  An unreliable LMP is associated with increased risk of adverse outcomes, especially fetal death.
authors.affiliation: Department of Ultrasound, Herlev Hospital University of Copenhagen, Herlev, Denmark. trihuu@dadlnet.dk
authors.forename: T H
authors.initials: TH
authors.lastname: Nguyen
authors.forename: T
authors.initials: T
authors.lastname: Larsen
authors.forename: G
authors.initials: G
authors.lastname: Engholm
authors.forename: H
authors.initials: H
authors.lastname: Møller
mesh_terms: D000328:Adult; D005260:Female; D005313:Fetal Death; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D016015:Logistic Models; D008598:Menstruation; D011247:Pregnancy; D011256:Pregnancy Outcome; D018570:Risk Assessment; D000509:alpha-Fetoproteins / Q000032:analysis
chemical_list: D000509:alpha-Fetoproteins