Are you Beverley Hewitt?

Claim your profile

Publications (5)17.84 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To identify first trimester indicators of adverse pregnancy outcomes. Data were obtained from the statewide evaluation of first trimester screening for Down syndrome in Western Australia which included 22,695 pregnancies screened between August 2001 and October 2003. Screening data were linked with pregnancy outcome information from the Hospital Morbidity Database and the Birth Defects Registry. The odds ratios (OR) of adverse outcomes were analysed for combined risk incorporating maternal age, nuchal translucency (NT) and biochemical parameters and then separately for each parameter (pregnancy-associated plasma protein-A (PAPP-A), free beta human chorionic gonadotropin (beta-hCG) and NT). Risk assessments for first trimester combined screening are derived from maternal age, ultrasound measurement of fetal NT, maternal serum free beta-hCG and PAPP-A. Increased combined risk for Down syndrome was significantly (P < 0.01) associated with spontaneous loss at or before 24 weeks gestation (OR 13.51), birth defects (OR 6.58) and preterm birth at or before 32 weeks gestation (OR 3.2). Maternal serum PAPP-A below the 5th centile was associated with Down syndrome (OR 8.43), spontaneous loss before 24 weeks (OR 5.04) and later than 24 weeks (OR 4.50), preterm delivery before 32 weeks (OR 3.11) and before 37 weeks (OR 2.24). NT above the 95th centile was associated with Down syndrome (OR 43.91), birth defects (OR 4.02) and spontaneous loss before 24 weeks (OR 6.24). Low levels of free beta-hCG and increased NT were less consistently associated with adverse outcomes and high levels of free beta-hCG showed limited use as an indicator. The detection rates for all outcomes other than Down syndrome were less than 40%. Biochemical indicators and NT that are measured during first trimester screening for Down syndrome show a number of associations with adverse outcomes, but do not show appropriate performance characteristics for screening tests. These data are consistent with the view that the individual components, specifically low PAPP-A levels alone, do not provide an effective screening tool for adverse pregnancy outcomes.
    No preview · Article · Jan 2009 · Australian and New Zealand Journal of Obstetrics and Gynaecology
  • Source
    B. G. Hewitt · S. L. Barrett · C. Bower · N. C. Hadlow

    Preview · Article · Oct 2007 · Ultrasound in Obstetrics and Gynecology
  • [Show abstract] [Hide abstract]
    ABSTRACT: This study assessed fetal outcomes for pregnancies identified at increased risk for Down syndrome by first-trimester combined ultrasound examination and maternal serum biochemistry screening. First-trimester combined screening data were obtained from ultrasound clinics across Western Australia between August 2001 and October 2003. Prenatal screening data were linked with pregnancy outcome information held in state health database registers using probabilistic record-linkage techniques. In 50 of the 60 pregnancies affected by Down syndrome, the adjusted risk was greater than 1 in 300, providing a detection rate of 83% (95% confidence interval [CI] 74-93%). Among all women screened (n = 22,280), 827 had increased risk results but did not have a Down syndrome pregnancy, representing a false-positive rate of 3.7% (95% CI 3.5-3.9%). Ten cases of Down syndrome were detected among women considered not at increased risk, consistent with a false-negative rate of 1 in 2,227. First-trimester combined screening reduced the number of Down syndrome births by 50 in 22,280 (2.24 cases per 1,000 births), which represents the detection of one case of fetal Down syndrome for every 446 women screened. Furthermore, 25% of pregnancies with other birth defects occurred among those identified at increased risk of Down syndrome, and 1 in 8 pregnancies at increased risk were found to have a significant chromosomal or structural defect. First-trimester combined screening in Western Australia detected 83% (95% CI 74-93%) of Down syndrome pregnancies at a 3.7% (95% CI 3.5-3.9%) false-positive rate. II-2.
    No preview · Article · May 2006 · Obstetrics and Gynecology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Two years of community-based first trimester screening (FTS) were audited. All women with singleton pregnancy in a defined health region who completed FTS (ultrasound and biochemistry) were included (n= 10,436) and outcomes obtained for 98.4%. All scans were performed or supervised by experienced sonologists with Fetal Medicine Foundation (FMF) accreditation. FMF software generated all risk assessments based on nuchal translucency (NT), maternal serum-free beta human chorionic gonadotropin (beta-hCG) and pregnancy-associated plasma protein A (PAPP-A). The detection rate for Trisomy 21 was 90.6% with a screen-positive rate of 3.9%. These findings indicate that where FTS is accessible within routine antenatal care, a detection rate of 90% and low screen-positive rate can be achieved using the FMF programme.
    Full-text · Article · Dec 2005 · BJOG An International Journal of Obstetrics & Gynaecology
  • Source

    Full-text · Article · Sep 2005 · Ultrasound in Obstetrics and Gynecology