[Multiple pregnancies in Denmark 1980-1994].
The objective was to study trends in national rates of multiple pregnancies that were not explained by changes in maternal age and parity. Information on childbirths to Danish-born women were obtained from national registers. The national incidence of multiple pregnancies increased 1.7-fold during 1980-1994, the increase primarily in 1989-1994 and almost exclusively in primiparous women > or = 30 years, for whom the adjusted population-based twinning rate increased 2.7-fold and the triplet rate 9.1-fold. The proportion of multiple births among infant deaths in primiparous women > or = 30 years increased from 11.5% to 26.9%. In conclusion, the marked increase in the rate of multiple pregnancies, which in particular was observed during the 1990s and in primiparous women > or = 30 years, could not be explained by changes in maternal age or parity. Fertility-enhancing treatments are believed to have caused this increase.
Westergaard
T
T
Afdeling for Epidemiologisk Forskning, Statens Serum Institut, København, .
Wohlfahrt
J
J
Aaby
P
P
Melbye
M
M
D000328:Adult; D003718:Denmark / Q000453:epidemiology; D005260:Female; D020073:Gravidity; D006801:Humans; D007231:Infant, Newborn; D008423:Maternal Age; D010298:Parity; D011247:Pregnancy; D011272:Pregnancy, Multiple / Q000706:statistics & numerical data*; D012042:Registries; D014310:Triplets; D014427:Twins
Flerfoldsfødsler i Danmark 1980-1994.