Second trimester ultrasound screening performed by midwives; sensitivity for detection of fetal anomalies

Abstract

When performing a second trimester ultrasound screening program, prenatal diagnosis of fetal anomalies will be part of the procedure whether this is a primary aim or not. It is therefore of great importance that the pregnant women receive adequate information and that the voluntariness of participation is stressed. In this study the sensitivity was low. Standardizing the scanning procedure (check-list for fetal anatomy) and improving the education of the operators are feasible ways to increase the sensitivity.

Routine ultrasound examination at 12 or 18 gestational weeks for prenatal detection of major congenital heart malformations? A randomised controlled trial comprising 36 299 fetuses

“…It is often not possible to calculate the rate of abnormal four-chamber view on the basis of data presented in articles either because of uncertainty about the total number of women scanned 12,13,20 or because the number of cases with abnormal or uninterpretable four-chamber view is not given. 14,26,27 Our rate of prenatal diagnosis of heart malformations in the 12-week scan group was even lower than that in the 18-week scan group (5,7 or 11% depending on how detection rate is defined versus 15%), although the differences were not statistically significant. Lack of statistical significance is almost certainly to be explained by low power.…”

“…Our 18-week policy was associated with a disappointingly low rate of prenatal diagnosis of major cardiac malformations (15%), although our prenatal detection rate fell within the range of detection rates reported in prospective studies conducted in settings that seem to have been similar to ours (0-75%). [9][10][11]13,14,[16][17][18][19] The extremely wide variation in reported prenatal detection rates of heart malformations at routine mid-gestation scans (0-81% [9][10][11][12][13][14][15][16][17][18][19][20]26,27 ) is to be explained not only by differences in operator skills but also by differences in study design (retrospective 20,26,27 or prospective [9][10][11][12][13][14][15][16][17][18][19] ), study population (unselected, [10][11][12][13][14][15][16]26,27 low risk ...…”

“…Results from prospective studies show that the detection rate of major heart defects at routine ultrasound examination at 18-23 gestational weeks in unselected or low-risk populations varies from 0 to 81%. [9][10][11][12][13][14][15][16][17][18][19] In a national survey from the UK including 4000 cases of major cardiac defects, the antenatal detection rate was 23%. 20 This survey is retrospective and does not distinguish between detection at routine and indicated scans.…”

Detection of malformations in chromosomally normal fetuses by routine ultrasound at 12 or 18 weeks of gestation—a randomised controlled trial in 39 572 pregnancies

“…gastroschisis or anencephaly) as statistically significant but is sufficiently large to detect differences in overall detection rate of malformed fetuses as statistically significant. Assuming a detection rate of 45% (mean detection rate in a review by Bricker et al 1 ) or 22% (detection rate in a Swedish study from Uppsala performed in a setting similar to that in our trial 16 ), a prevalence of fetal malformations of 2% and using an alpha error (two sided) of 0.05 and a beta error of 0.1, our sample size would allow detection of a change in detection rate from 45 to 33% or from 22 to 13%. Statistical analyses were carried out using the Statistical Package for the Social Sciences (SPSS Inc., Chicago, IL, USA; 2003).…”

Prenatal diagnosis of structuralmal formations and chromosome anomalies : Detection, influence of Body Mass Index and ways to improve screening

“…The reported overall sensitivity for the detection of structural malformations during routine screening ultrasound varies considerably between studies (Bricker 2000). The reported detection rate of fetal malformations in the second trimester screening varies between 19 and 80% (Boyd 1998;Eurenius 1999;Stefos 1999;Saltvedt 2006). The ability to detect structural malformations in the first and early second trimester has improved so that detection rates (15-54%) are almost comparable to those from gestational week 18-20 (Carvalho 2002;Chen 2004;Taipale 2004;Cedergren 2006;Saltvedt 2006;Souka 2006).…”