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.
Using the Danish Fertility Database, we investigate intergenerational fertility transmission, including the relationship between the number of children born to those aged 25 and 26 years in 1994 and the number of their full sibs and half-sibs. We find that the fertility behaviour of parents and their children is positively correlated, and that half-sibs and full sibs have broadly similar effects. We do not find, in this complete national population, the strong birth order effects reported in some earlier studies. Nor do we find evidence of a weakening of intergenerational fertility transmission over time, perhaps because the greater flexibility of lifestyles in this post-transitional phase provides the extended social space within which intergenerational continuities can manifest themselves. We show that members of large families are over-represented in subsequent generations - that they have far more kin than those from smaller families - and that intergenerational continuities in fertility behaviour play a substantial role in keeping fertility higher than it would be in the absence of such transmission.
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.
Birthweights in the Faroe Islands are among the highest in the world. Compared with Denmark, the average birthweight of liveborn singleton infants of primiparous mothers is 194 g higher, and a substantial part of this difference seems to be attributable to longer gestation. Prostaglandins play an important part in the timing of parturition in human beings. Dietary (n-3)-polyunsaturated fatty acids (PUFA) in high amounts influence endogenous prostaglandin metabolism. Owing to the large consumption of marine fat, the average intake of (n-3)-PUFA in the Faroes by far exceeds that in Denmark. The hypothesis proposed is that dietary (n-3)-PUFA in high amounts prolong gestation in human beings by interfering with uterine production of prostaglandins, possibly by inhibiting the production of dienoic prostaglandins, primarily PGF2 alpha and PGE2, which are mediators of uterine contractions and cervical ripening.