ABSTRACT
BACKGROUND: The aim of this study was to assess the value of two-stage screening by ultrasonography in detecting selected major fetal anomalies in a low-risk obstetric population. METHODS: In a defined geographic area, 4789 consecutive low-risk pregnant women participated in screening by two-stage ultrasonography as part of routine maternal care. The examinations were usually performed by specially trained midwives at 13-14 and 18-22 weeks of gestation. Of the women, 4073 had both scans, 440 had the early one only, and 276 the late scan only. Pregnancy outcomes were ascertained from obstetric and pediatric records, and the data were supplemented with information from the national birth and malformation registries. RESULTS: Of the 4855 fetuses, 33 (0.7%) had major structural defects considered detectable by ultrasonography. Of these, six (18%) were identified at the early scan, and an additional 10 (30%) at the late scan, yielding a total sensitivity of 48% for the two-stage screening. Twenty offspring had chromosomal abnormalities; 10 were identified by increased nuchal translucency at the early scan, one additional one (by hydronephrosis) at the late scan, and the remaining nine at birth. CONCLUSIONS: In a low-risk population, first-trimester scanning is useful in finding fetuses with chromosomal anomalies, but a second-trimester scan is needed for other types of defects. The sensitivity of routine screening by midwives for fetal structural defects in a general obstetric population remains lower than that reported by specialized centers.
Subject(s)
Congenital Abnormalities/diagnostic imaging , Midwifery/methods , Pregnancy Complications/diagnosis , Ultrasonography, Prenatal , Adult , Chromosome Aberrations/embryology , Congenital Abnormalities/embryology , Female , Humans , Mass Screening , Midwifery/standards , Nuchal Translucency Measurement , Pregnancy , Pregnancy Outcome , Pregnancy Trimester, First , Pregnancy Trimester, Second , Sensitivity and SpecificityABSTRACT
We analyzed surveillance data on group B streptococcus (GBS) infection in Finland from 1995 to 2000 and reviewed neonatal cases of early-onset GBS infection in selected hospitals in 1999 to 2000. From 1995 to 2000, 853 cases were reported (annual incidence 2.2-3.0/100,000 population). We found 32-38 neonatal cases of early-onset GBS disease per year (annual incidence 0.6-0.7/1,000 live births). In five hospitals, 35% of 26 neonatal cases of early-onset GBS infection had at least one risk factor: prolonged rupture of membranes, preterm delivery, or intrapartum fever. Five of eight mothers screened for GBS were colonized. In one case, disease developed despite intrapartum chemoprophylaxis. Although the incidence of early-onset GBS disease in Finland is relatively low, some geographic variation exists, and current prevention practices are suboptimal. Establishing national guidelines to prevent perinatal GBS is likely to reduce the incidence of the disease.
Subject(s)
Population Surveillance , Streptococcal Infections/epidemiology , Streptococcus agalactiae/isolation & purification , Adolescent , Adult , Child , Child, Preschool , Female , Finland/epidemiology , Humans , Incidence , Infant , Infant, Newborn , Male , Middle Aged , Registries , Streptococcus agalactiae/pathogenicity , Surveys and QuestionnairesABSTRACT
OBJECTIVE: To assess the value of first trimester screening by ultrasonography in detecting structural anomalies of the fetus in a general obstetric population. METHODS: During 1993-1998, 20,465 consecutive pregnant women who resided in a defined geographic area participated in ultrasonographic screening for major malformations. These included anomalies of the central nervous system, urinary tract, abdominal wall, and long bones. Heart anomalies were not expected to be detected. The examinations were offered at 13-14 weeks' gestation as part of routine maternal care and were done by specially trained midwives. The pregnancy outcomes were ascertained from obstetric and pediatric records, and the data were completed by information from the national birth and malformation registries. RESULTS: A total of 307 fetuses (1.5%) with a major malformation were found; 67 fetuses (0.3%) had noncardiac major structural defects expected to be detectable by ultrasonography in early pregnancy. Thirty-five of 67 (52%) were identified at the early scan. Sensitivity for these defects increased from 22% to 79% from the first to the last (sixth) study year (P =.009). CONCLUSION: In a low-risk population, adequate sensitivity in screening for major malformations by early ultrasonography can be achieved after a learning curve of 3-4 years.
