美国生育率下滑至历史新低

Fertility rates in the United States are continuing their decades-long decline, due in large part to a steep slide in teenage pregnancies down to historic lows, according to a new government report released Thursday.

The National Center for Health Statistics said the pregnancy rate of 102 pregnancies out of every 1,000 women is 12 percent below the 1990 peak of about 116 per 1,000. Only once in the past 30 years, 1997, has it been lower, and only marginally, the center said.

Since 1990, the report said, pregnancy rates are down in almost every category. The only exception is among women over 30, whose pregnancy rate has increased steadily with every passing year. But the rate is declining among women in their 20s, who form the single largest group of pregnant women, and among teenagers of all races and ethnicities. The abortion rate also has dropped, reflecting a continuous slide since peaking in 1990.

The report only examined the trajectory of pregnancy rates through 2009, stopping there because more recent data on abortions is not available yet. But newer statistics on birth rates suggest thedecline is continuing, though not as quickly as it did in recent years when the recession accelerated trends well underway.

Women already were having fewer children than women of their parents’ and grandparents’ generations, so those under 30 could postpone childbirth until the economy improved without affecting their longstanding goals of having a first or second child.

“What happened was a postponement of births among younger women with a longer time horizon,” said Andrew Cherlin, a Johns Hopkins University sociologist specializing in family issues. “Women over 30 couldn’t wait that much longer.”

While the decelerating decline in birth rates since 2009 reflects the easing of the recession’s impact, the striking drop in teenage pregnancies shows little sign of abating. The teen pregnancy rate in 2009, of about 38 per thousand girls, was 39 percent lower than the 1991 peak of 62. Just four years later, in 2017, it reached a record low of about 29.

Sally Curtin, one of the report’s authors, said the historic drop is being driven by a long, downward trend of fewer teenagers having sex, and among those who do, a sharp increase in their use of contraceptives.

“It’s as if both sides in the debate over teen pregnancy were right,” said Cherlin, noting that concerns over the AIDS epidemic may have played a role in the growing use of condoms among teenage boys.

“AIDS has forced many school districts to talk about contraception, even if they didn’t want to,” he said.

The national trends are evident in the Washington area.

Teenage pregnancy rates have plummeted in the District, down to less than a quarter of where they were two decades ago, said Brenda Rhodes Miller, director of the DC Campaign to Prevent Teen Pregnancy. In 1993, the pregnancy rate for teenagers aged 15 to 19 was about 239 per 1,000. By 2011, it was under 55.

“The decline has been amazing,” she said, adding that the reasons for it are not clear.

Teen pregnancy rates are declining in every ward, she said, though more slowly in wards 7 and 8, which have the city’s lowest income levels. More than 500 of the 879 births to District teens in 2011 were to residents of those two wards.

The one-year drop was relatively small. In more affluent wards, the teen pregnancy rate dropped by double digit percentages.

Even with declining pregnancy rates, the United States still has one of the highest overall birth rates among industrialized countries. The 10 nations with the highest birth rates in the world are all in Africa.

11月5日发布的政府工作报告指出，美国的怀孕率几十年来持续走低，很大程度上是由于青少年怀孕率大幅下滑至历史新低的缘故。

国家健康统计中心表示，与1990年的高峰时期——每千名妇女中116名怀孕相比，怀孕率下降了12%，至每千人102名。在过去30年间，只有1997年的怀孕率比现在略低。

工作报告还指出，从1990年起，各个年龄段的怀孕率都呈下降趋势。只有30岁以上的妇女例外，她们的怀孕率每年都在稳步上升。但是，对所有种族而言，20多岁的妇女作为怀孕女性的主力军，其怀孕率却持续下降。流产率自1990年达到最高值后持续走低。

这一报告只总结到2009年的怀孕率变化轨迹，之后关于流产率的数据现在还没有统计。然而，从最新的出生率可以看出，怀孕率仍在降低，速度却在减缓，不像近几年经济萧条时期下幅那样明显。

现在的妇女普遍比她们的父辈与祖父辈生的孩子少。所以，不到30岁的夫妻，可以等到经济条件比较好时再生孩子，这并不影响他们要1个、2个孩子的计划。

美国约翰霍普金斯大学的安德鲁·切尔林是一位专门研究家庭方面的问题社会学家，他表示：“现在的年轻妇女推迟生育的时间更长。而30岁以后的妇女们则会选择尽早生育。”

2009年后出生率下降速度减缓，这表明经济衰退带来的影响在逐渐减轻，但青少年怀孕的数量仍在大幅降低，丝毫没有缓解的迹象。2009年青少年怀孕率大概为每千人38人，比1991年时的最高值（每千人中62人怀孕）下降39%。而在2017年，这一比率达到历史新低：每千人有29人怀孕。

其中一位报告编写者萨利·科廷表示，越来越少的青少年进行性行为已成为一个长期趋势，而那些进行性行为的青少年，越来越多的采取避孕药等避孕措施，这推动了怀孕率的持续下跌。

科廷还表示，似乎支持与反对青少年怀孕都有其正确之处。他还指出，因为担心感染艾滋病，越来越多的男青年选择使用避孕套。

他说：“艾滋病的蔓延使得许多学校开设关于避孕的教育课程，即使学校不想如此。”

在华盛顿地区，这一趋势非常明显。

华盛顿地区防止青少年怀孕活动的主管布伦达·罗兹表示，在这一地区，青少年怀孕率骤降，降至不到20年前比率的1/4。1993年，15-19岁的青少年怀孕率约为每千人中239人怀孕，到2011年时，这一数据已降至每千人中不到55人怀孕。

她还说：“这一下降幅度实在是太大了。”并表示，导致这一现象的原因还不清楚。

她说，青少年怀孕率在每个区都呈下降趋势，而在7区和8区这两个收入水平最低的地区，怀孕率降低速度较慢。2011年，华盛顿地区的879名新生儿中，500名来自这两个区。

本年度的降幅相比前几年不算大。但较富裕区的青少年怀孕率仍以2位数的比率下跌。

尽管国内怀孕率持续走低，美国依旧是发达国家中出生率最高的国家之一。全世界出生率最高的10个国家都在非洲。