title: Value of adding second-trimester uterine artery Doppler to patient characteristics in identification of nulliparous women at increased risk for pre-eclampsia: an individual patient data meta-analysis.
abstract: OBJECTIVE
  To investigate the value of adding second-trimester uterine artery Doppler ultrasound to patient characteristics in the identification of nulliparous women at risk for pre-eclampsia.
  
  
  METHODS
  For this individual patient data meta-analysis, studies published between January 1995 and December 2009 were identified in MEDLINE and EMBASE. Studies were eligible in which Doppler assessment of the uterine arteries had been performed among pregnant women and in which gestational age at ultrasound, Doppler ultrasound findings and data on the occurrence of pre-eclampsia were available. We invited corresponding authors to share their original datasets. Data were included of nulliparous women who had had a second-trimester uterine artery Doppler ultrasound examination. Shared data were checked for consistency, recoded to acquire uniformity and merged into a single dataset. We constructed random intercept logistic regression models for each of the patient and Doppler characteristics in isolation and for combinations. We compared goodness of fit, discrimination and calibration.
  
  
  RESULTS
  We analyzed eight datasets, reporting on 6708 nulliparous women, of whom 302 (4.5%) developed pre-eclampsia. Doppler findings included higher, lower and mean pulsatility index (PI) and resistance index (RI) and any or bilateral notching. Of these, the best predictors were combinations of mean PI or RI and bilateral notching, with areas under the receiver-operating characteristics curve (AUC) of 0.75 (95% confidence interval (CI), 0.56-0.95) and 0.70 (95% CI, 0.66-0.74), respectively. Addition of Doppler findings to the patient characteristics blood pressure or body mass index (BMI) significantly improved discrimination. A model with blood pressure, PI and bilateral notching had an AUC of 0.85 (95% CI, 0.67-1.00).
  
  
  CONCLUSIONS
  The addition of Doppler characteristics of mean PI or RI and bilateral notching to patient characteristics of blood pressure or BMI improves the identification of nulliparous women at risk for pre-eclampsia.
authors: Department of Obstetrics and Gynaecology, Academic Medical Center, Meibergdreef 9, Amsterdam, The Netherlands. c.e.kleinrouweler@amc.uva.nl
authors: C E
authors: CE
authors: Kleinrouweler
authors: P M M
authors: PM
authors: Bossuyt
authors: B
authors: B
authors: Thilaganathan
authors: K C
authors: KC
authors: Vollebregt
authors: J
authors: J
authors: Arenas Ramírez
authors: A
authors: A
authors: Ohkuchi
authors: K L
authors: KL
authors: Deurloo
authors: M
authors: M
authors: Macleod
authors: A E
authors: AE
authors: Diab
authors: H
authors: H
authors: Wolf
authors: J A M
authors: JA
authors: van der Post
authors: B W J
authors: BW
authors: Mol
authors: E
authors: E
authors: Pajkrt
mesh_terms: D000293:Adolescent; D000328:Adult; D001794:Blood Pressure / Q000502:physiology; D015992:Body Mass Index; D005260:Female; D005865:Gestational Age; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D011225:Pre-Eclampsia / Q000000981:diagnostic imaging*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second / Q000502:physiology*; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018608:Ultrasonography, Doppler; D016216:Ultrasonography, Prenatal / Q000379:methods*; D055988:Uterine Artery / Q000000981:diagnostic imaging*; D055815:Young Adult
keywords: Doppler ultrasound; individual patient data meta-analysis; pre-eclampsia; prediction; uterine artery