Introduction: Denmark was the first country in the world to implement a national, free‐for‐all offer of prenatal screening for Down syndrome to all pregnant women. It has a high uptake (>90%) compared to other countries. Thus, Denmark offers an interesting case for investigating the consequences of implementing comprehensive, national prenatal screening guidelines. The aim of this study was to describe the historical developments in invasive procedures, pre‐/postnatal diagnoses of Down syndrome and Down syndrome live births in the period 1973–2016 in Denmark.Material and methods: Data on invasive procedures, pre‐ and postnatal Down syndrome diagnoses were retrieved from the Danish Cytogenetic Central Registry.Results: From 1973 to 1993, screening based on maternal age and high‐risk indications resulted in a constant increase in invasive procedures. After the introduction of the triple test in 1994, invasive procedures decreased for the first time in 20 years. Following the introduction of an offer of combined screening to all pregnant women in 2004, the number of invasive procedures decreased markedly, while there was a concurrent increase in prenatal diagnoses of Down syndrome. Additionally, the number of Down syndrome live births decreased suddenly and significantly, but subsequently stabilized at 23–35 annual live births. Of these, the majority were diagnosed postnatally.Conclusion: Though prenatal screening technologies constantly improve, it was the introduction of and adherence to national guidelines that resulted in marked shifts in screening procedures and outcome in Denmark.

Objective: To evaluate the performance of maternal risk factors (BMI and mean arterial pressure [MAP]) and first-trimester maternal serum markers in the early prediction of preeclampsia (PE) in nulliparous women. Material and Methods: This was a case-cohort study based on a cohort of 14,207 nulliparous women. A total of 213 cases with term PE (from 37 weeks + 0 days) and 55 cases with preterm PE (before 37 weeks + 0 days) were identified and validated. Randomly, 449 controls were selected. Serum samples previously collected for the double test (pregnancy-associated plasma protein A [PAPP-A] and free β human chorionic gonadotrophin [hCGβ]) as part of the first-trimester screening program were retrieved and analyzed for placental growth factor (PlGF), soluble fms-like tyrosine kinase 1 (sFlt-1), N-terminal pro-B-type natriuretic peptide (NT-proBNP), and neutrophil gelatinase-associated lipocalin (NGAL). Concentrations were transformed to multiples of the median (MoM). Multivariate regression analysis was used for prediction models. Receiver-operating characteristics (ROC) curves were used for evaluation of the screening performance. Results: In preterm PE, the PlGF (0.79 MoM), sFlt-1 (0.86 MoM), NGAL (1.15 MoM), and PAPP-A (0.89 MoM) medians were significantly altered. In term PE, PlGF (0.90 MoM) and NT-proBNP (0.86 MoM) medians were significantly reduced. The combination of MAP and PlGF yielded a 39% detection rate of preterm PE for a 10% false-positive rate. The combination of MAP, BMI, and PlGF yielded a 33% detection rate of term PE with a 10% false-positive rate. Conclusion: First-trimester MAP, maternal serum PlGF, and NGAL are markers of preterm PE. Maternal serum sFlt-1 is a significant marker of preterm PE, but only early in the first trimester. First-trimester maternal serum NT-proBNP is not a predictor of PE. Screening performance for PE with these markers individually or in combination is modest.

Regular audit of results of prenatal screening for congenital heart disease (CHD) is crucial to ensure reliable prenatal diagnosis. We aimed to assess the accuracy of prenatal diagnosis of major CHD between 1996 and 2013. During the study period, prenatal detection of major CHD improved from 4.5% to 71.0% (p<.001). Prenatal diagnoses on 628 live born children and terminated pregnancies were compared with postnatal findings or autopsy reports. The proportion of correct diagnoses increased throughout the study period from 42.9% in 1996 and reached 88.2% in 2013 (p<.001). A total of 32 foetuses with suspected major CHD were terminated though no major CHD was found at autopsy. In these pregnancies, termination was mainly performed due to other anomalies in the foetus. Along with improved detection of major CHD, the validity of a prenatal diagnosis is increasing. No cases of misinterpreted major CHD resulted in the termination of a healthy foetus in this study.