Women's opinions and the implications of first- versus second-trimester screening for fetal Down's syndrome

Two groups of pregnant women were questioned regarding their opinions on serum screening for Down's syndrome in the first trimester of pregnancy. One group comprised 83 women attending our antenatal clinic who were questioned at the time of the existing second-trimester screening test. Seventy-six per cent of those who participated in the second-trimester screening programme would have preferred the test to have been in the first trimester, mainly because of the easier termination of pregnancy and/or the earlier reassurance provided. The remaining 24 per cent could see no advantage in the earlier time frame. Of the 49 women who had declined second-trimester screening, only two would have participated in screening had it been in the first trimester. The other group comprised those women attending our antenatal diagnosis clinic who were considering chorionic villus sampling (CVS). Forty-four per cent of these women would have allowed serum screening in the first trimester to influence their decision as to whether to undergo definitive prenatal diagnostic testing. In general, those women who made use of second-trimester serum screening would also do so in the first trimester. Those who declined the existing screening programme would also decline first-trimester screening. Many women currently deciding to undergo CVS would allow a first-trimester screening test to influence their decision. (C) 1997 by John Wiley & Sons, Ltd

Maternal urinary beta-core hCG in chromosomally abnormal pregnancies in the first trimester

We evaluated urinary beta-core human chorionic gonadotropin (beta-core hCG) in the detection of fetal Down's syndrome (DS) in the first trimester of pregnancy. Urine was collected prior to performing chorionic villous sampling (CVS) between 10 and 12 completed weeks from the last menstrual period. In the 9 months of the study, there were 15 chromosomal abnormalities detected by CVS: five trisomy 21, four monosomy X, two trisomy 18, and four cases of confined placental mosaicism (CPM). In these 15 aneuploid pregnancies, the levels of urinary beta-core hCG were expressed as multiples of the median (MOM) of the ratio of beta-core hCG/creatinine for gestational age. The MOMs of this ratio in each of the five DS pregnancies were 0.2, 0.5, 1.3, 1.4, and 1.7. No difference was found between fetuses with DS or any of the other chromosomal abnormalities tested and normal fetuses. Contrary to optimistic reports of urinary beta-core hCG in the second-trimester detection of fetal DS, our data suggest that this is not a useful screening test for DS in the first trimester of pregnancy. (C) 1997 by John Wiley & Sons, Ltd

Trends in live birth prevalence of Down syndrome in the Northern Netherlands 1987-96: the impact of screening and prenatal diagnosis

In the Northern Netherlands, we examined the live birth prevalence of Down syndrome (DS) and the impact of maternal serum screening (MSS) and prenatal cytogenetic diagnosis (PCD) during the period 1987-96. In this period the live birth prevalence, based on the maternal age distribution and the age specific risk of delivering a child with DS was expected to increase from 1.26 in 1987 to 1.62 in 1996. The introduction of MSS in 1991 made PCD available to women of all ages. Nevertheless, the utilization of PCD remained very stable. In 1991, 4.7% of pregnant women underwent a diagnostic test. In 1996 this percentage was 6.4%. As a result of MSS and PCD, the live birth prevalence of DS was 19% lower than expected (