Epidemiologic data were analyzed for a total of 2,693 infants with esophageal atresia registered in nine congenital malformation registries around the world. The average recorded prevalence at birth was 2.6 per 10,000 births, with a significant variability among programs--and sometimes within a program--and a maximum prevalence of above 3 per 10,000 births. Clusters of infants with esophageal atresia were observed but may be random. An increasing rate was seen during the period 1965 to 1975 (Norway, South America, Sweden). The type of esophageal atresia was specified in only 439 cases, but no major differences were seen in the epidemiologic characteristics of infants with the most common type (distal fistula) and infants with other types. There was an excess of low birth weight and preterm birth, and infants with esophageal atresia had a birth weight 500 to 1,000 g less than normal infants in each gestational week. There was an excess of twins, apparently mainly or exclusively due to monozygotic twinning, but in only two pairs did both twins have esophageal atresia. There was no effect seen of maternal age, but low parity, irrespective of maternal age, was associated with an increased risk for esophageal atresia. Infant survival varied among programs and depended heavily on associated malformations. Among 1,107 sibs born before the proband and 385 born after the proband, only 25 (1.7%) had a serious malformation; three had esophageal atresia. In 57.3% of the infants with esophageal atresia, no other malformations were present, in 36.4% other major malformations were recorded, and in 6.3% there were chromosomal anomalies. The malformations present associated with esophageal atresia were analyzed: a large proportion entered the constellation sometimes called "caudal mesoderm spectrum of malformations": VATER, Potter, and caudal regression sequences.
OBJECTIVES: To study in detail the differences in infant mortality between Denmark and Sweden. STUDY DESIGN: Data retrieved from national health registers on infant death rates were compared for 1980-1988, supplemented with a study on the impact of socio-economic conditions in 1985-86 (Denmark) or 1986 (Sweden). RESULTS: Even after stratification for maternal age, parity, and socio-economic group, the Danish mortality rate was higher in all age-at-death intervals except for stillbirths. Maternal age-parity distribution was more favourable in Denmark, the socio-economic distribution in Sweden. The most marked country differences was seen in young women. The difference in the rate of perinatal deaths but not of later deaths is explainable by a more favourable birth weight distribution in Sweden than in Denmark. CONCLUSIONS: The studied variables do not explain the difference in mortality risk but it may be due to life style factors so far not identified.
Information on parity from the Medical Register of Births kept by The Danish National Board of Health was compared with a parity value calculated with the aid of a new, individual-based Fertility Database compiled by the Danmarks Statistik. The parity information contained in the Medical Register of Births is recorded by the midwife at each birth, where the woman's number of previous live-births is noted. The Register on Population Statistics records live-born infants with reference to their mother, and parity is calculated in the Fertility Database on the basis of these records. The results show a very high degree of accordance between the two measures of parity. More than 99.5% of women with parity one who have given birth since 1978 are classified as such by both systems. Due to an ambiguity in the midwife's birth notification form there has previously been uncertainty regarding the classification of first-time mothers based on the information contained in the Medical Register of Births. This evaluation shows that this information can be regarded as valid.