越来越多的美国孕妇吸食大麻，有何后果？

大麻，这种既可以用于娱乐，又可以用于医疗的物质，在过去几年里行情一直见涨。美国各州都在（以某些形式）推行它的合法化。而合法大麻的销售额预计将在2017年达到惊人的100亿美元。不过，这种植物的繁荣对公众健康的长期影响仍然不甚明朗——而最新的研究显示，很大一部分年轻孕妇都在使用大麻，随之引发的疑问是：它会对这些准妈妈的胎儿产生何种影响？

哥伦比亚大学（Columbia University）的研究人员发现，3.9%的孕妇（以及7.6%处在生育年龄的非孕妇）在2007年至2012年间使用过大麻。研究作者写道：“从2002年到2014年，有过大麻使用经历的孕妇人数增加了62%。大麻在18岁到25岁的女性中最为流行，这意味着年轻女性更有可能在怀孕期间使用大麻。”

数字本身并不至于引发恐慌。正如作者指出，有关大麻对健康影响的研究仍处于相对起步阶段。不过已有一些研究推测，孕期使用大麻与新生儿体重较轻、大脑发育程度较低或有关联。

孕妇大麻使用量增加的情况是否属于药物滥用，目前也难以界定。例如，医用大麻最普遍的用法是缓解恶心和焦虑（这俩都是怀孕的常见反应），这或许可以部分解释用量增加的原因。不过，正如哥伦比亚大学的研究人员指出的那样，由于大麻在社会上的风靡，我们有必要密切关注使用者的身份，以及它可能给健康带来的目前未知的潜在影响。（财富中文网）

译者：严匡正

Marijuana—recreational and medicinal alike–has been on a tear over the past several years. States are legalizing it (in some form or another) left and right; legal cannabis sales are projected to reach an astounding $10 billion in 2017. But the weed boom’s long-term effect on public health is still murky—and a new study suggests that a larger share of younger, pregnant women are using marijuana, raising questions about how its use may affect the fetuses of expectant mothers.

Columbia University researchers found that 3.9% of pregnant women (and 7.6% of non-pregnant women of reproductive age) reported using marijuana in the previous month between 2007 and 2012. “Among pregnant women, the prevalence of past-month marijuana use increased 62% from 2002 through 2014. Prevalence was highest among women aged 18 to 25 years, indicating that young women are at greater risk for prenatal marijuana use,” wrote the study authors.

The numbers aren’t a cause for alarm in and of themselves. As the authors note, marijuana health effect research is relatively new. But there are some studies which suggest there may be a relationship between marijuana use during pregnancy and lower birth weight or brain development in offspring.

It’s also unclear that the increased marijuana use by pregnant women represents drug abuse; for instance, nausea and anxiety (both common among pregnancy) are among the most common symptoms of medical marijuana users, which may in part explain the increase in usage. But, as the Columbia researchers note, as cannabis use balloons across society, it’s important to keep tabs on who’s using it—and on potential health effects we don’t currently know about.