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Objective: To compare the efficacy of fetal nuchal translucency screening, maternal serum screening and combined screening for Down syndrome., Design: A prospective study., Setting: University hospital and its public health care district in Northern Finland., Population: A total of 35,314 women participated in the first-trimester screening for Down syndrome within the public healthcare system in 2002-08. There were 95 pregnancies involving Down syndrome. Serum samples were obtained from 35,314 women, nuchal translucency was measured in 27,144 pregnancies and full combined screening was performed in those pregnancies, including 76 involving Down syndrome., Methods: The adjusted estimated risk for Down syndrome was calculated using the Perkin Elmer AutoDELFIA® time-resolved fluoroimmunoassay kit for the measurement of pregnancy-associated plasma protein-A and free β-human chorionic gonadotropin. Nuchal translucency was measured by trained personnel in a university or district hospital. Risk cut-off figures 1:250 and 1:300 at term were used., Main Outcome Measures: Differences in detection rate, false-positive rate, positive and negative predictive values between nuchal translucency screening, serum screening and combined screening., Results: Using the risk cut-off figure 1:250, the detection rates for serum screening, nuchal translucency screening and combined screening were 64.2, 64.5 and 72.4%, respectively and the false-positive rates were 7.8, 4.4 and 4.0%, respectively., Conclusions: Combined screening is the method of choice for Down syndrome screening in Finland., (© 2013 Nordic Federation of Societies of Obstetrics and Gynecology.)

Objectives: We evaluated the performance of first trimester screening for Down syndrome in women less than 35 years of age (study group) and in women aged 35 years or more (control group) in an unselected low-risk population., Methods: The study group comprised a total of 63,945 women who participated in the first trimester combined screening in public health care in Finland during the study period of 1 May 2002 to 31 December 2008. Women at the age of 35 or more (n = 13,004) were controls. Prevalence of Down syndrome, detection rate, false positive rate and number of invasive procedures needed to detect a single case of Down syndrome were analyzed in both groups., Results: The overall prevalence of Down syndrome (n = 73) in the study group was 1:876. The number of detected cases was 54. The detection rate was 74.0% with a false positive rate of 2.8%. Number of invasive procedures needed to detect a single case of Down syndrome was 33. In the control group, the detection rate was 87.0% with a false positive rate of 11.9%. The number of invasive procedures needed to detect a single case of Down syndrome was 15. The differences in detection rate and false positive rate were significant, P < 0.012, P < 0.001, respectively., Conclusion: The overall detection rate given for the entire population is an overestimate for a woman younger than the age of 35, which should be taken into consideration when counselling women of that age., (© 2012 Blackwell Publishing Ltd.)

We analyzed the frequency and possible causes of false-negative (Fn) screening results in first-trimester combined Down syndrome screening in Finland. During the study period (May 1, 2002, to December 31, 2008), 76,949 voluntary women with singleton pregnancies participated in screening. Maternal age at screening, week of gestation, levels of pregnancy-associated plasma protein-A (PAPP-A), free β-human chorionic gonadotropin (fβ-hCG), and nuchal translucency (NT) measurement were compared and statistically analyzed between true-positive (Tp) and Fn cases. There were a total of 188 Down syndrome cases (1:409) in the screened population; 154 confirmed Tp and 34 Fn cases. Most Fn cases (n = 25) occurred at 12 + 0 to 13 + 6 weeks' gestation and only nine Fn cases presented between 10 and 11 weeks' gestation. According to the logistic regression analysis, the NT measurement was the most powerful discriminating factor in Fn screening results and accounted for 37.2% of Fn results. The second most important factor was fβ-hCG, adding 14.0% to R(2), followed by PAPP-A, which contributed a further 14.3%. The chosen parameters explain 83.9% of Fn results, but 16.1% remain due to unknown factor(s). All investigated parameters contributed to Fn screening results, but fetal NT was the most discriminating factor leading to an Fn screening result., (Copyright © 2012 by Thieme Medical Publishers, Inc.)

Objective: To evaluate the performance of first-trimester combined screening in 5-year periods according to maternal age in a low-risk population., Design: A prospective study., Setting: Multicenter study in Finland., Population: A total of 76949 voluntary women with singleton pregnancies participated in first-trimester combined screening in public healthcare between 1 May 2002 and 31 December 2008., Methods: The serum samples were analyzed using the PerkinElmer AutoDELFIA® time-resolved fluoroimmunoassay kit for the measurement of pregnancy-associated plasma protein-A and free beta-human chorionic gonadotropin. Nuchal translucency was measured by trained personnel (midwives or physicians) in a university or central hospital., Main Outcome Measures: Performance, detection rate, false positive rate and the number of invasive procedures needed to detect a single case of Down's syndrome were analyzed., Results: There was a direct connection between maternal age and the prevalence of Down's syndrome with a low prevalence in young women being 1:1 193 in the 25-29 age group and 1:150 in the 35-39 age group. Consequently, for a fixed false positive rate of 5%, the number of invasive procedures needed to detect one case of Down's syndrome is higher in younger women to achieve the same detection rate., Conclusions: In combined first trimester screening the risk for Down's syndrome is individual, varying with maternal age. This should be taken into consideration when counseling women., (© 2011 The Authors Acta Obstetricia et Gynecologica Scandinavica© 2011 Nordic Federation of Societies of Obstetrics and Gynecology.)

The characteristics of the Finnish parturient have changed in recent years. The mean age of mothers at first delivery is now 29.3 years and the number of women > 35 years of age has increased to 19%. This shift has led to an increase in the prevalence of Down's syndrome. Between 1 January 2002 and 31 December 2006, there were 795 cases of Down's syndrome (27/10,000) in the Finnish Register of Congenital Malformations. The distribution of Down's syndrome in terminated pregnancies and newborns was analyzed in 5-year periods based on maternal age. The distribution of Down's syndrome cases in younger women (< 35 years) and in older women (> or =35 years) at the time of delivery was compared. The majority of new Down's syndrome cases occurred in the group having older women (61.1%), even though 35 years is the arbitrary threshold.

Background: The performance of first trimester biochemical screening was compared at different pregnancy weeks and maternal ages during 2002-2008 in a screened population of 76,949 women. Methods: The detection rates, as well as the median multiples of a median (MOMs) of free β-human chorionic gonadotropin (free β-hCG) and pregnancy-associated plasma protein-A (PAPP-A), were compared between completed gestational weeks 8-13 and between different maternal ages separated into 5-year groupings. Results: The number of singleton Down syndrome pregnancies was 221. The median age of the screened women was 30 years and the proportion of women aged ≥35 years 16.9%. The median age of the women with a Down syndrome pregnancy was 37 years. In women aged <35 years, the biochemical markers provided a detection rate of only 38.6%, whereas in women aged ≥35 years, the biochemical markers detected 82.7% of cases (p<0.01). Conclusions: Biochemical screening works best amongst women aged ≥35 years. For younger mothers aged <35 years, combined screening should be the method of choice. [ABSTRACT FROM AUTHOR]

Objective. To examine the performance of first-trimester combined screening after adding the specific algorithms for trisomies 18 and 13 in the Down syndrome screening program for chromosomal abnormalities other than trisomy 21 and to determine the outcomes of such pregnancies. Design. A retrospective study. Setting. Oulu University Hospital, Finland. Population. Pregnant women ( n=56 076) participating voluntarily in first-trimester combined Down syndrome screening in Northern and Eastern Finland during the study period 1 June 2002 to 31 December 2008. Methods. The data of all known cases of chromosomal abnormalities other than trisomy 21 were collected. Main Outcome Measures. Risk algorithms for trisomies 21, 18 and 13 were used for the calculation of patient-specific risks for certain chromosomal abnormalities. Algorithms were based on maternal age, crown-rump length, nuchal translucency, and measurement of free β-human chorionic gonadotrophin and pregnancy-associated plasma protein-A. Detection rates and false-positive rates were calculated. Results. A total of 27 cases of trisomy 18, 11 cases of trisomy 13 and 30 cases of other chromosomal abnormalities were analyzed. The algorithm for Down syndrome detected 55.6% of trisomy 18 cases, 36.4% of trisomy 13 cases and 60.0% of other chromosomal abnormalities. When specific risk algorithms were added, the detection rates improved for trisomy 18 (74.0%) and for trisomy 13 (54.5%), with only a slight increase of the false-positive rate of 0.2%. The detection rate for other chromosomal abnormalities did not improve. Conclusions. Adding the trisomy 18 algorithm to the Down screening program resulted in the detection of five additional trisomy 18 cases. [ABSTRACT FROM AUTHOR]