Just like any other multivitamin, prenatal supplements come chock full of vitamins and minerals intended to benefit mothers-to-be and their unborn bundles of joy.
产前营养品和任何一种复合维生素一样，都富含各种维生素和矿物质，对准妈妈们和未出生的宝宝似乎大有益处。
But while some of those nutrients are important, there are many more that might be unnecessary, according to a new paper published in the British Medical Journal’s Drug and Therapeutics Bulletin on Monday.
但是本周一，英国医学期刊的药物与治疗公告上的最新研究表明，虽然有些营养素很重要，但是很多都不是孕妇必须的。
It turns out that only folic acid and vitamin D have any evidence to support their use in dietary supplements for pregnancy, said Dr. James Cave, editor-in-chief of the bulletin and a practitioner at the Downland Practice in Newbury, Berkshire.
公告总编詹姆斯·凯威博士表示孕妇所需的膳食补充剂只有叶酸和维生素D，他也是伯克郡纽伯里地区的一位执业医师。
I think we were surprised, Cave said. "Vitamin deficiencies are common in women of child-bearing age and you would therefore expect there to be plenty of good evidence that taking a multivitamin helps in some way."
“我想我们对此都很惊讶”，凯威说，“怀孕期间的妇女常常出现维生素不足的症状，所以就会认为服用复合维生素是很有帮助的。”
Prenatal vitamins are often marketed as a way to get all of the vitamins and minerals an expectant mother and her unborn baby need that may not be provided in a daily diet. Prenatal supplements can cost as much as $16.64 per month in the United Kingdom, according to the paper.
孕妇服用的维生素常常这样推销，声称可以为孕妇和胎儿补充日常膳食中缺乏的所有维生素和矿物质。该研究表明，在英国，这些产前营养品每个月大约要花费16.64美元。
"Women can be reassured that taking a folic acid supplement ... and vitamin D is all they need to do, and can save themselves a great deal of money not buying expensive branded multivitamins, Cave said. "If they have any specific concerns about a vitamin or mineral deficiency they should discuss this with their doctor or pharmacist."
“女士们完全可以放心，只服用叶酸......和维生素D就足够了，不需要购买昂贵的品牌复合维生素，这会为他们节约一大笔钱的”，凯威说，“如果她们对某种维生素或矿物质缺乏有针对性的担忧，他们应该咨询他们的医生和药剂师。”
Digging through the data
深入数据分析
For the paper, dozens of previous studies, systematic reviews and individual trials were reviewed. The researchers examined the evidence available for supporting the use of folic acid, iron and vitamins D, C, E and A, among other nutrients, in prenatal supplements.
在该研究报告中，列举了多个了之前的研究，系统综述和单个实验。产前营养补充品的各种营养素中，是否可以含有叶酸，铁，维生素D，C，E和A研究人员调查了相关证据。
Many of the previous studies were carried out in countries where expectant mothers have poorer nutrition than in the United Kingdom, Cave said. The researchers aimed to focus on the needs of the United Kingdom population.
之前的许多研究都是在其他一些国家进行的，那里的孕妇比英国孕妇更容易出现营养不良的状况，凯威说。这次，研究人员主要是针对英国孕妇的需要。
The researchers did not identify clear evidence that vitamins and nutrients other than folic acid and vitamin D helped to prevent birth complications. Rather, the use of supplements containing vitamin A was not recommended during pregnancy.
除了叶酸和维生素D，研究人员并未发现明显的证据，证明其他的维生素和营养素可以阻止分娩并发症的发生。相反，他们甚至不建议孕妇服用还有维生素A的营养品。
The paper concluded that folic acid has the strongest evidence support, followed by vitamin D, which was less clear cut. "What we found was that the human is a tougher being than perhaps we realize and seems to be able to function completely well with some vitamin levels lower than are considered normal," Cave said.
该研究的结论是，叶酸是最该补充的，其次是维生素D。“我们发现人体是很坚强的，比我们意识到的还要厉害，即便是某些维生素低于正常值的情况下，依旧可以正常运作”，凯威说。
What’s recommended, what’s not
孕期营养补充的建议和需要注意的问题
However, some doctors are quick to point out that these findings are not representative of the needs of expectant mothers in the United States.
然而，有些医生很快指出，这些研究对于美国的孕妇是不具有代表性的。
While the American Congress of Obstetricians and Gynecologists has no specific guidance about whether or not pregnant women need to take a prenatal vitamin, Dr. Scott Sullivan, a fellow at the group, said that taking specific evidence-based minimums of nutrients are suggested:
美国妇产科医师学会的斯科特·沙利文博士表示，美国妇产医师学会没有明确规定孕妇是否要服用产前维生素，建议服用最少量的已经证实可用的营养素：
400 micrograms of folic acid
400微克叶酸
27 milligrams of iron
27毫克铁
1,000 milligrams of calcium
1000毫克钙
600 international units of vitamin D
600国际单位维生素D
It is certainly more convenient to take one supplement rather than five things and probably improves compliance, said Sullivan, an associate professor at the Medical University of South Carolina who was not involved in the new paper.
“服用一种营养品比服用五种不同的营养品，更方便些，也更容易提高遵规性”，沙利文说，他也是南卡罗来纳州医科大学的副教授，并未参与这项新研究。
It’s not time to abandon the multivitamin or prenatal vitamin and it’s not one size fits all, he said. "Nutrition is important in pregnancy, and should be maximized. The choice of prenatal vitamins should be individualized, made in conjunction with a woman’s OB-GYN or provider, with attention to the minimums mentioned."
“是时候停止服用复合维生素和产前维生素了，这不是一个包治百病的方法”，他说，“怀孕期间补充营养很重要，而且应该大量补充。但是产前维生素的选择应该针对个人，而且应该咨询妇产科医师和医疗服务人员，并留意最少服用多少。“
Even though doctors may have differing thoughts on the importance of supplements, many agree on what foods should be a part of a pregnant woman’s diet.
即使医生对于营养品的重要性观点不同，但是他们大多同意，应该从食物中摄取营养。
For instance, a growing consensus is that cooked seafood, such as salmon, tilapia or cod, is beneficial, Sullivan said.
比如，越来越多的医师认为煮熟的海鲜，像三文鱼，罗非鱼，鳕鱼对孕妇是很有益处的，沙利文说。
"It’s really interesting that women were scared of seafood because of mercury, which absolutely mercury is terrible, but that’s a very small amount of what’s available in seafood, Sullivan said. "There’s conclusive evidence that for women who eat a regular amount of seafood during pregnancy, their children may have better performance on cognitive and motor tests."
“有趣是的很多孕妇害怕吃海鲜，担心含有汞，纯粹的汞当然是很可怕的，但是海鲜里的含量是微乎其微的”，沙利文说，“有确凿证据表明，怀孕期间常常吃海鲜的妇女，他们的孩子在认知和体能测试上的表现都优于其他孩子。”
Additionally, he recommends that pregnant women eat a balanced diet of fruits, vegetables, grains, proteins and dairy.
除此之外，他还建议孕妇饮食要均衡，多吃水果，蔬菜，谷物，蛋白质和奶制品。
