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.
With few exceptions, the number of births fell steadily in Denmark between the mid-60s and 1983, when 51,087 children were born, the lowest number on record. Since 1984 the number of births has risen and in 1989 about 61,700 children were born. In the period with declining number of births, the number of voluntary abortions fell nearly as much. After the law on permissive abortion went into effect on October 1, 1973, the number of abortions rose rapidly to a maximum of 27,884 in 1975, after which it declined steadily to 19, 919 in 1986 with a weak rise to 21,456 in 1989. Danish statistics on the total number of conceptions showed a steady decrease from 1974 through 1982 but a change to an increase after 1983. A parallel decrease in the fraction of conceptions carried to term also reversed after 1983. In 1973-74 the frequency of conception among women of fertile age was 85/1000; in 1982-83, 63.5; and in 1988-89, nearly 72. Spontaneous abortions rose by 1/3 from 8300 in 1982 to 11,600 in 1989. The sample does not reveal how much of the observed increase is due to increased hospital admission in early miscarriages and how much to a real increase. Age group statistics show that the number of teen pregnancies has fallen about 10% since 1982 while the numbers have risen for all other age groups. The strongest rise has been among the 30-34 year group, where the number of pregnancies has risen 20% since 1982.
A Danish study of birth and abortion statistics for the years 1976-1979 shows that, although the absolute incidence of deliveries and induced abortions has steadily declined during this period, the percentage of deliveries (65%) and induced abortions (25-27%) compared to the number of conceptions has remained constant. Between 1976-1978, induced abortion became relatively more frequent among those under 20 years of age and less frequent among those 25-39 years of age, even though the actual number of abortions has decreased for all age groups.
The declining number of live births, surgical abortions, and the relatively unchanged number of spontaneous abortions in Denmark during a 5 year period in 1977-1981 are analyzed. The health care system and hospitals provided statistical data for this study. The number of live births decreased by approximately 14% from 1977 to 1981 (62,247 - 53,370); however, conceptions also fell 16% during the period 1973/74 - 1980/81 (100,000 - 84,000). The rate of conception was 82/1000 fertile women in 1976-77, but only 69/1000 in 1980-81. Legally induced abortions were significantly fewer in 1979 (23,378) than in 1977 (26,402); nevertheless, in 1980-81 about 30% of all pregnancies were terminated. For this same year, a decrease in the number of abortions was noticeable in the 25-34 year age group, but an increase from 54% to 60% was observed in the under 20 year age group. The fertility pattern was greatly influenced by the declining number of pregnancies in the 20-29 year age group, since they give birth to 70% of the newborns. In 1981, the birth rate fell about 8% (or 4000 births), and the number of abortions dropped by 800 or 2%. The figures for 1982 indicate a 2% decline in births and a decrease in abortions of 1000. Age group-specific adjustment of these figures will reveal whether or not this trend will continue.