title: Placental site in the second trimester of pregnancy and its association with subsequent obstetric outcome.
abstract: OBJECTIVE
  To determine if placental location in the second trimester of pregnancy is associated with adverse pregnancy outcomes.
  
  
  METHODS
  We performed a retrospective study on 16 236 patients having ultrasound examination at 14 to 23 weeks of gestation between 2000 and 2007. The placental location was classified into one of four groups: 'central', 'fundal', 'lateral' and 'covering Os'. Obstetric outcomes of non-central placenta were compared to those with 'central' placenta.
  
  
  RESULTS
  Women with a 'fundal' placenta were at increased risk of developing pre-eclampsia (PET) (odds ratios (OR) = 2.27; 95% confidence intervals (CI), 1.31-3.93), a preterm delivery before 34 weeks (OR = 2.23; 95% CI, 1.18-4.22), a non-vertex presentation (OR = 3.48; 95% CI, 2.49-4.86), undergoing a manual removal of placenta (MROP) following a vaginal delivery (OR = 7.1; 95% CI, 4.24-11.85) and small for gestational age (SGA) (OR = 1.35; 95% CI, 1.03-1.79). Women with a 'lateral' placenta were at increased risk of developing PET (OR = 2.04; 95% CI, 1.28-3.25), spontaneous preterm delivery before 34 weeks (OR = 2.04; 95% CI, 1.04-3.98), MROP (OR = 6.75; 95% CI, 4.4-10.33) and SGA (OR = 1.82; 95% CI, 1.48-2.23). Five women with a 'cover Os' placenta had an increased risk of postpartum haemorrhage (>1000 mL) (OR = 6.18; 95% CI 2.29-16.65) if they had a vaginal delivery.
  
  
  CONCLUSIONS
  Non-central placental location in the second trimester is associated with an increase risk of adverse obstetric outcome.
authors.affiliation: Department of Obstetrics and Gynaecology, The Chinese University of Hong Kong, The Prince of Wales Hospital, Shatin, Hong Kong SAR, China. drtyfung@yahoo.com.hk
authors.forename: Tak Yuen
authors.initials: TY
authors.lastname: Fung
authors.forename: Daljit Singh
authors.initials: DS
authors.lastname: Sahota
authors.forename: Tze Kin
authors.initials: TK
authors.lastname: Lau
authors.forename: Tak Yeung
authors.initials: TY
authors.lastname: Leung
authors.forename: Lin Wai
authors.initials: LW
authors.lastname: Chan
authors.forename: Tony Kwok Hung
authors.initials: TK
authors.lastname: Chung
mesh_terms: D000328:Adult; D036861:Delivery, Obstetric / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D010920:Placenta / Q000166:cytology / Q000000981:diagnostic imaging / Q000502:physiology*; D011225:Pre-Eclampsia / Q000000981:diagnostic imaging / Q000453:epidemiology; D011247:Pregnancy; D011248:Pregnancy Complications / Q000000981:diagnostic imaging / Q000453:epidemiology; D011256:Pregnancy Outcome / Q000453:epidemiology; D011262:Pregnancy Trimester, Second / Q000502:physiology*; D012189:Retrospective Studies; D016216:Ultrasonography, Prenatal; D014599:Uterus / Q000000981:diagnostic imaging; D055815:Young Adult