title: Second trimester biparietal diameter size and the risk of adverse pregnancy outcomes.
abstract: OBJECTIVE
  To identify the relationship between biparietal diameter (BPD) in the second trimester and adverse pregnancy outcomes in low-risk pregnancies.
  
  
  METHODS
  This prospective cohort study was performed on 2219 singleton pregnant women from August 2008 to March 2010. The gestational age-specific percentiles of BPD at 17 to 24 weeks of gestation were established to categorize participants into three groups: a BPD < 10th percentile as small BPD, between 10th and 90th percentile as normal BPD and > 90th percentile as large BPD. Using logistic regression analysis, the association between BPD < 10th and > 90th percentile with pregnancy outcomes was evaluated after controlling for confounding factors.
  
  
  RESULTS
  There was a significantly increased risk of macrosomia [odds ratio (OR(adj)) = 2.1; 95% confidence intervals (CI), 1.23-3.78] and preterm labor (PTL) (OR(adj) = 1.9; 95% CI, 1.19-3.05) in fetuses with a BPD > 90th percentile compared with fetuses with a normal BPD, and there was a significant relationship between small for gestational age (SGA) at delivery and a BPD < 10th percentile at the second trimester (OR(adj) = 2.4; 95% CI, 1.77-3.52). No association was present between preeclampsia and second trimester BPD.
  
  
  CONCLUSIONS
  BPD in the first half of pregnancy is related to fetal size at term and risk of PTL.
authors: Perinatology Division, Obstetrics and Gynecology Department, Tehran University of Medical Sciences, Tehran, Iran.
authors: Vajiheh
authors: V
authors: Marsoosi
authors: Reihaneh
authors: R
authors: Pirjani
authors: Ashraf
authors: A
authors: Jamal
authors: Laleh
authors: L
authors: Eslamian
authors: Abbas
authors: A
authors: Rahimi-Foroushani
mesh_terms: D000328:Adult; D000886:Anthropometry / Q000379:methods*; D005260:Female; D005320:Fetal Macrosomia / Q000453:epidemiology*; D005865:Gestational Age; D006257:Head / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D007492:Iran / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D007752:Obstetric Labor, Premature / Q000453:epidemiology*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D011446:Prospective Studies; D016216:Ultrasonography, Prenatal