BACKGROUND & AIMS:
:Since the early 1980s, the number of births to women over age 35 has been increasing in most European countries. Consequently, the period of highest fertility shifted from the 20-25 to the 25-30 age range. During the baby boom after World War II in France, the annual number of births rose from 610,000 in 1938 to 870,000 by the end of the 1940s. In 1964 when the baby boom children reached reproductive age, annual births were close to 850,000. The number of births in mothers over 35 increased from 47,000 in 1980 to 70,000 in 1985. The total fertility ratio was 3 children/woman by the end of the 1940s, then it declined to 1.8 between 1964 and 1976, below the replacement level up to the present time. The proportion of the ratio attributable to women over 35 age declined during the 20th century from 25% to the current 9%. Between 1964 and 1976, all the age-specific birth rates fell. In France in 1978, unwanted births dropped from 21% to 13.5% between the periods 1963 and 1967, and 1973 and 1977, respectively. In 1976, fertility in the 25-39 and the 30-34 age ranges started to increase. The main reason for the increase in fertility beyond age 35 was the decrease in nuptiality at younger ages due to more efficient birth control. Illegitimate fertility rates also rapidly increased along with single women at all ages. In Sweden, the illegitimacy ratio is currently close to 1 out-of wedlock birth in every 2 births. The illegitimacy ratio nearly doubled between 1976 and 1985 to reach 17% in the UK and 20% in France. It is not close to 6% in Switzerland, 8.5% in the Netherlands, and 9% in West Germany. On the one hand, the increase in the number of births at maternal ages over 35 occurred because the baby boom cohorts are not 25-40 year old. New cohorts will marry later and often get divorced, while out-of-wedlock fertility continues to increase. These changes will bring about the decline in fertility before age 25 and an increase between ages 25 and 35. Late fertility after age 35 will probably increase to a much smaller extent than mid-period fertility.
背景与目标:
:自1980年代初以来,大多数欧洲国家/地区中35岁以上女性的分娩数量一直在增加。因此,最高生育率的时期从20-25岁转变为25-30岁。在法国第二次世界大战后的婴儿潮时期,每年的出生人数从1938年的61万增加到1940年代末的870,000。 1964年,婴儿潮时期的孩子达到了生殖年龄,每年的出生人数接近850,000。 35岁以上母亲的出生人数从1980年的47,000人增加到1985年的70,000人。到1940年代末,总生育率是3个孩子/妇女,然后在1964年至1976年间下降到1.8个,低于替代水平直到现在的时间。在20世纪,归属于35岁以上女性的比例从25%下降到目前的9%。在1964年至1976年之间,所有特定年龄的出生率均下降。 1978年的法国,在1963年和1967年以及1973年和1977年之间,意外生育率分别从21%下降到13.5%。 1976年,年龄在25-39岁和30-34岁之间的生育率开始增加。 35岁以后生育能力增加的主要原因是由于更有效的节育措施,年轻时的婚育性下降。与所有年龄段的单身女性一起,非法生育率也迅速增加。在瑞典,非婚生比率目前接近每2胎非婚生胎1胎。在1976年至1985年之间,非婚生率几乎翻了一番,在英国达到了17%,在法国达到了20%。瑞士的这一比例接近6%,荷兰为8.5%,西德为9%。一方面,由于婴儿潮一代的年龄不在25至40岁之间,因此孕产妇在35岁以上出生的人数有所增加。新婚夫妇将在以后结婚,并且通常会离婚,而婚外生育能力则继续增加。这些变化将导致25岁之前的生育力下降,以及25岁至35岁之间的生育率增加。35岁之后的后期生育率可能会比中期生育率的增长幅度小得多。