No abstract

The difference between population and primary care morbidity is affected by disease under investigation and patients' demographic characteristics. Therefore, in choosing the more cost-effective approach to collect data such evidence should be taken into account, and results should be interpreted with great caution.

This paper presents an 'optimal' procedure for the use of the 'sets' method, a system proposed for surveillance of congenital malformations. Comparisons over a number of examples shows that the given procedure represents a clear improvement over the one originally proposed, and, in some conditions, is more efficient than the cusum scheme.

Six cases of cystic hygromas detected during second trimester ultrasound examination are reported: 4 fetuses (67 per cent) had a 45, X karyotype, 1 fetus had trisomy 18, 1 fetus had a normal karyotype (46,XX) and at autopsy multiple anomalies were observed. In the latter case the family history suggested an autosomal recessive pattern of inheritance. In order to reach a definite diagnosis and give proper genetic counselling when a fetus is found to have cystic hygroma, a fetal karyotype as well as a family and reproductive history should be obtained.