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- Saltvedt, S, et al.
(författare)
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Screening for Down syndrome based on maternal age or fetal nuchal translucency: a randomized controlled trial in 39572 pregnancies
- 2005
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Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 25:6, s. 537-545
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Nuchal translucency (NT) screening increases antenatal detection of Down syndrome (DS) compared to maternal age-based screening. We wanted to determine if a change in policy for prenatal diagnosis would result in fewer babies born with DS. Methods A total of 39572 pregnant women were randomized to a scan at 12-14 gestational weeks including NT screening for DS (12-week group) or to a scan at 15-20 weeks with screening for DS based on maternal age (18-week group). Fetal karyotyping was offered if risk according to NT was >= 1 :250 in the 12-week group and if maternal age was >= 35 years in the 18-week group. Both policies included the offer of karyotyping in cases of fetal anomaly detected at any scan during pregnancy or when there was a history of fetal chromosomal anomaly. The number of babies born with DS and the number of invasive tests for fetal karyotyping were compared. Results Ten babies with DS were born alive with the 12-week policy vs. 16 with the 18-week policy (P = 0.25). More fetuses with DS were spontaneously lost or terminated in the 12-week group (45119 796) than in the 18-week group (27119 776; P = 0.04). All women except one with an antenatal diagnosis of DS at < 22 weeks terminated the pregnancy. For each case of DS detected at < 22 weeks in a living fetus there were 16 invasive tests in the 12-week group vs. 89 in the 18-week group. NT screening detected 71% of cases of DS for a 3.5% test-positive rate whereas maternal age had the potential of detecting 58% for a test-positive rate of 18%. Conclusions The number of newborns with DS differed less than expected between pregnancies that had been screened at 12-14 weeks' gestation by NT compared with those screened at IS-20 weeks by maternal age. One explanation could be that NT screening - because it is performed early in pregnancy - results in the detection and termination of many pregnancies with a fetus with DS that would have resulted in miscarriage without intervention, and also by many cases of DS being detected because of a fetal anomaly seen on an 18-week scan. The major advantage of the 1.2-week scan policy is that many fewer invasive tests for fetal karyotyping are needed per antenatally detected case of DS.
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- Saltvedt, S, et al.
(författare)
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Ultrasound dating at 12-14 or 15-20 weeks of gestation? A prospective cross-validation of established dating formulae in a population of in-vitro fertilized pregnancies randomized to early or late dating scan
- 2004
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Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 24:1, s. 42-50
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Tidskriftsartikel (refereegranskat)abstract
- Objectives To determine the accuracy of established ultrasound dating formulae when used at 12-14 and 15-20 gestational weeks. Methods A total of 363 singleton pregnancies conceived after in-vitro fertilization (IVF) and randomized to a dating scan at 12-14 or 15-20 gestational weeks were studied. 'True' gestational age was calculated on the basis of the day of oocyte retrieval and was compared to gestational age calculated on the basis of seven dating formulae including the fetal biparietal diameter (BPD) and three dating formulae including BPD and fetal femur length (FL). The mean of the differences between estimated and true gestational age (systematic measurement error) and their SD (random measurement error) were calculated for each formula. Results Three formulae showed systematic errors of less than -0.7 days at both early and late scanning. Two formulae overestimated gestational age at both early and late scanning by 5.7 and 3.1 vs. 2.3 and 2.8 days, respectively, while five formulae manifested very different systematic errors at early and late scanning. The formulae used for clinical management underestimated gestational age by a mean of 3 days when dating was performed at 12-14 weeks, and by a mean of 0.8 days when dating was done at 15-20 weeks. The random error was on average 1 day less when the scan was carried out early (2 vs. 3 days; P < 0.0005). Mean true gestational age at delivery in IVF pregnancies with spontaneous start of labor was 279 days (SD 12.9); excluding preterm deliveries it was 2 81 days (SD 8.1). Conclusions Ultrasound dating formulae originally intended for use in the middle of the second trimester do not necessarily perform well when used for dating earlier in gestation. The systematic and random error of any dating formula must be assessed for the gestational age interval in which the formula is intended to be used. Copyright (C) 2004 ISUOG. Published by John Wiley & Sons, Ltd.
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- Thorsell, M, et al.
(författare)
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Large fetal size in early pregnancy associated with macrosomia
- 2010
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Ingår i: Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. - : Wiley. - 1469-0705. ; 35:4, s. 390-394
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Tidskriftsartikel (refereegranskat)
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