First-trimester screening for down syndrome with serum sampling at different gestational ages: the effect on screening performance.

INTRODUCTION: The objective of this study was to evaluate the performance of first-trimester Down syndrome (DS) screening with serum sampling at different weeks of gestation. MATERIAL AND METHODS: We studied 35,431 singleton pregnancies (2005-2011), including 145 DS cases. Screening performance was determined in different maternal age groups with serum sampling between weeks 9 + 0 and 13 + 6. RESULTS: No significant differences were found between the detection rates at different gestational weeks. The false-positive rate (FPR) in week 9 (6%) was comparable to the FPR in week 10 (6.5%; p = 0.214), whereas it was significantly lower compared to weeks 11 (7.2%; p = 0.007), 12 (7.4%; p = 0.003) and 13 (8.5%; p < 0.001). The odds of receiving a false-positive result was significantly increased with serum sampling in week 11 (OR 1.32, 95% CI 1.08-1.63; p = 0.008) for women ≥36 years and from week 12 onwards (OR 1.28, 95% CI 1.01-1.61; p = 0.04) for women <36 years. There were no differences in mean log10 multiple of the median values of pregnancy-associated plasma protein-A, free ß-human chorionic gonadotrophin or nuchal translucency between both age groups, nor in mean maternal age between the different gestational weeks in either age group. DISCUSSION: Early serum sampling (<11 weeks) resulted in higher screening performance. The impact of the increase in the FPR was highest in women ≥36 years.

Validation of correction factors for serum markers for first-trimester Down syndrome screening in singleton pregnancies conceived with assisted reproduction.

OBJECTIVE: To validate previously computed correction factors for free ß-human chorionic gonadotrophin (fß-hCG) and pregnancy-associated plasma protein-A (PAPP-A) in in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) pregnancies with hormone treatment and to determine the effect on false-positive rate (FPR). METHODS: Retrospective study on 249 IVF and 250 ICSI cases and 20,190 controls. Correction factors 1.42 (PAPP-A), 1.17 (fß-hCG) in IVF; 1.56 (PAPP-A) in ICSI were applied on the absolute serum concentrations. Analysis was done on log10-transformed multiples of medians (MoMs). RESULTS: In the controls, mean PAPP-A and fß-hCG MoM were 1.004 and 1.062. Before correction, mean PAPP-A MoM was significantly lower in IVF (0.757; p < 0.001) and in ICSI (0.671; p < 0.001) and after correction comparable (1.071; p = 0.053 in IVF; 1.048; p = 0.178 in ICSI). Before correction, mean fß-hCG MoM was comparable (1.054; p = 0.59 in IVF and 1.051; p = 0.56 in ICSI) and after correction significantly higher in IVF (1.241; p < 0.001). After correction the likelihood for receiving a false-positive result was 1.03 in IVF pregnancies (95% CI 0.98-1.09; p = 0.248) and 1.02 in ICSI pregnancies (95% CI 0.97-1.07; p = 0.448). CONCLUSIONS: After correction the FPR in IVF and ICSI pregnancies with hormone treatment reduces to the observed FPR in the controls.

Performance of first-trimester combined test for Down syndrome in different maternal age groups: reason for adjustments in screening policy?

OBJECTIVE: To evaluate the performance of the first-trimester combined test (FCT) in different maternal age groups and to discuss whether adjustments in screening policies should be made. METHODS: In this retrospective study data (n = 26 274) from a fetal medicine center on FCT (maternal age, fetal NT, free ß-human chorionic gonadotrophin, pregnancy-associated plasma protein-A) were studied. RESULTS: 70.6% of cases was <36 years and 43% of the Down syndrome (DS) cases were detected in this age group. For women <36 years and advanced maternal age (AMA) women (≥36 years) detection rate (DR) and false positive rate (FPR) were 94.5% and 4.1%, and 95.8% and 13.0%, respectively (cut-off 1:200). Lowering the cut-off showed an improved balance in DR and FPR. With increasing maternal age FPR and DR increased and odds of being affected given a positive result (OAPR) decreased. CONCLUSION: FCT is effective in women <36 and ≥36 years. The balance between FPR and DR is more favourable in women <36 years with comparable OAPR. Although FPR increases with increasing maternal age, performance of FCT in AMA women is more effective than screening based on maternal age alone. Lowering the cut-off to 1:100 in AMA women is suggested to improve screening performance. Routinely offering diagnostic testing to AMA women as a screening policy for the detection of DS seems not reasonable.

Isolated Increased Nuchal Translucency in First Trimester Ultrasound Scan: Diagnostic Yield of Prenatal Microarray and Outcome of Pregnancy.

Background: Increased nuchal translucency (NT) is associated with aneuploidy. When the karyotype is normal, fetuses are still at risk for structural anomalies and genetic syndromes. Our study researched the diagnostic yield of prenatal microarray in a cohort of fetuses with isolated increased NT (defined as NT ≥ 3.5 mm) and questioned whether prenatal microarray is a useful tool in determining the adverse outcomes of the pregnancy. Materials and Methods: A prospective study was performed, in which 166 women, pregnant with a fetus with isolated increased NT (ranging from 3.5 to 14.3 mm with a mean of 5.4 mm) were offered karyotyping and subsequent prenatal microarray when karyotype was normal. Additionally, all ongoing pregnancies of fetuses with normal karyotype were followed up with regard to postnatal outcome. The follow-up time after birth was maximally 4 years. Results: Totally, 149 of 166 women opted for prenatal testing. Seventy-seven fetuses showed normal karyotype (52%). Totally, 73 of 77 fetuses with normal karyotype did not show additional anomalies on an early first trimester ultrasound. Totally, 40 of 73 fetuses received prenatal microarray of whom 3 fetuses had an abnormal microarray result: two pathogenic findings (2/40) and one incidental carrier finding. In 73 fetuses with an isolated increased NT, 21 pregnancies showed abnormal postnatal outcome (21/73, 28.8%), 29 had a normal outcome (29/73, 40%), and 23 were lost to follow-up (23/73, 31.5%). Seven out of 73 live-born children showed an adverse outcome (9.6%). Conclusions: Prenatal microarray in fetuses with isolated increased NT had a 5% (2/40) increased diagnostic yield compared to conventional karyotyping. Even with a normal microarray, fetuses with an isolated increased NT had a 28.8% risk of either pregnancy loss or an affected child.

Evaluation of the introduction of the national Down syndrome screening program in the Netherlands: age-related uptake of prenatal screening and invasive diagnostic testing.

OBJECTIVE: To study the effect of different government prenatal screening (PNS) policies on the uptake of PNS and prenatal diagnostic testing (PND) over the periods 2001-2003 (PNS on request), 2004-2006 (permission to offer the first-trimester combined test (FCT) to women of advanced maternal age (AMA), with women aged <36 years informed on explicit request) and 2007-2010 (introduction of population screening) and to evaluate whether trends in uptake are related to maternal age. The indication AMA for PND is still warranted, and the costs for FCT are only reimbursed for AMA women. STUDY DESIGN: Analysis of data on the first- and second-trimester screening program (n=41,600) for Down syndrome (DS) and on PND (n=10,795) performed from 2001 to 2010 in the region North-Holland of the Netherlands. To evaluate the actual participation in PNS and PND in different maternal age groups, estimation of the age distribution of women who underwent a fetal anomaly scan in 2009 (n=14,481) was used as a reference population (participation of 85.2%). RESULTS: The overall uptake of FCT was 35.2% in 2010. Over the years the number of FCT in all age groups increased significantly (P<0.001). Overall the number of PND decreased significantly; the number of PND for AMA decreased and the number of PND for increased risk at FCT (in women <36 and ≥36 years) increased (P<0.05). Since 2004 significantly more DS cases were detected with FCT in AMA women and fewer with PND for AMA, and since 2007 more DS cases were detected with FCT in women <36 years (P<0.001). CONCLUSION: The effect of the national screening program is limited. Significantly more women opt for PNS but the overall uptake remains low, especially in younger women. A significant number of AMA women still opt for PND for AMA. The choice for FCT and PND for AMA seems dependent on background risk. To accomplish a more effective screening policy, reimbursement of the cost of the test should apply to all women and the indication for PND for AMA should be abolished.

Prenatal diagnosis of aneurysms of the vein of Galen (vena magna cerebri) with conventional sonography, three-dimensional sonography, and magnetic resonance imaging: report of 2 cases.

OBJECTIVE: To describe the cases of 2 fetuses with aneurysms of the vein of Galen diagnosed prenatally. METHODS: The techniques used were conventional sonography, three-dimensional sonography, and ultrafast magnetic resonance imaging. On the basis of these imaging modalities, prognostic factors, such as drainage and secondary damage, were assessed. RESULTS: The first fetus had good prognostic indices, and embolization after birth was successful. According to the prognostic factors, a poor neonatal outcome was predicted for the second fetus. The neonate died soon after birth. CONCLUSIONS: Conventional sonography, color Doppler imaging, and magnetic resonance imaging appeared to be useful diagnostic tools. The prognostic factors can be useful in counseling patients and providing the best possible care after birth.