美国研究人员发现，不论贫穷或富裕，生育过多个孩子的妇女往往会有更多的牙齿脱落。一项由康涅狄格州纽约大学和耶鲁大学在美国进行的大规模研究，首次发现了这一结果。在此之前，其他国家也发现过类似的结果，尤其是20世纪80年代以来斯堪的纳维亚人的相关研究。

共有2635名18至64岁的美国妇女参加了本次研究，她们被分为代表国家整体水平的三个组别：低、中、高的社会经济地位组别。在社会经济组较高的组别中，未生育过孩子的妇女平均脱落不到一个牙齿，生育过一个孩子的妇女平均脱落两个牙齿，而生育过四个或四个以上孩子的妇女平均会脱落五个牙齿。据牙科医学专家Stefanie Russell博士（该项研究的负责人，他们的研究成果发表在《美国公共健康杂志》上）介绍说，社会经济组较低和中等的组别中的妇女具有类似的趋势。

“人们可能会说，牙齿脱落的发生是由于有更多的孩子的妇女生活贫穷，不能担负牙科医疗费用，”Russell在接受路透社的电话采访时说。“但是，我们发现各个社会经济地位组别的妇女的情况都是一样的。”妇女在怀孕期间更容易患牙龈炎，这时口腔组织对口腔内细菌的改变产生了应答。

此外，妇女在怀孕期间可能不太去看牙医，也许部分原因是她们希望避免牙科X射线检查所致的辐射。由于缺乏金钱和时间，生育过多个孩子的妇女也可能会忽视自己的牙齿护理，Russell说。

英文原文：

Women who gave birth to more children tended to lose more teeth during their lives, regardless of whether they were rich or poor, US researchers found. A large study conducted by the New York University and Yale University in Connecticut was the first in the US to show such findings. Earlier studies elsewhere have shown similar results, in particular Scandinavian research from the 1980s.

A total of 2635 US women ages 18 to 64 were examined in the study, sorting the nationally representative sample into three categories - low, middle and high socio-economic status. In the highest socio-economic group, women with no children were missing on average less than one tooth, those with one child were missing about two teeth and those with four or more were missing about five teeth. The trend also held true in lowest and middle socio-economic group, according to dental professor Dr Stefanie Russell, who led the research published in the American Journal of Public Health.

"People might say that tooth loss happens because women who are poor have more children and are not going to be able to afford the dentist,” Russell said in a telephone interview to Reuters. “But we found that it was true across all socio-economic levels.” Women are more prone to gingivitis during pregnancy, when the response of the oral tissues to the bacteria in the mouth is altered, she added.

Moreover, women may be less likely to see a dentist while pregnant, perhaps in part because they want to avoid dental X-rays due to concern over radiation exposure. Women with multiple children may also forget their own dental care, possibly due to lack of money or time, Russell said.