※ 引述《SkySlaughter (※天空屠杀者※)》之铭言： : 孕妇若在怀孕期间服用过量维生素A便容易导致畸胎的发生，包括胎儿的脸部畸形、脑水 : 肿、视神经病变、唇颚裂、先天性心脏病、脑神经机能障碍、发育迟缓等问题，因此孕 : 妇在摄取任何营养剂或食物时，要注意是否含有过高的维生素A，或是摄取的量适不适 : 当，以免让自己的宝宝遭受伤害。 : 以上所述 几乎每个选项都可以选 : 而且题干是问"可能"有关 : 建议更正後答案为(A)(B)(C)(D) : 附议者请推一下文谢谢 William obsterics, 23ed Vitamin A There are two natural forms of vitamin A. Beta-carotene is a precursor of provitamin A. It is found in fruits and vegetables and has never been shown to cause birth defects (Oakley and Erickson, 1995). Retinol is preformed vitamin A. Many foods contain vitamin A, but animal liver contains the most. Several reports of prenatal supplementation have associated high doses of vitamin A with congenital anomalies. However, they were clouded by small numbers, unknown daily dose, and absence of any recognizable pattern of observed defects. Two cohort studies have also been inconclusive (Conway, 1958; Rothman and co-workers, 1995). The only prospective study included 423 women who contacted European Teratology Services to report exposure (Mastroiacovo and associates, 1999). These women had ingested from 10,000 to 300,000 IU of vitamin A daily during the first 9 weeks of pregnancy. Only three exposed newborns had birth defects, and there was no relationship between vitamin dose and outcome. It seems reasonable to avoid doses higher than the recommended daily allowance of 5000 IU (American College of Obstetricians and Gynecologists, 1995). Nohynek and colleagues (2006) found that human topical exposure to retinol- or retinyl ester-containing cosmetic creams at 30,000 IU/day did not affect plasma levels of retinol, retinyl esters, or retinoic acids. 题干只写了Vitamin A，但是William's里面写的Vitamin A根本没有造成畸胎的evidence 另外後面有提到 Isotretinoin is considered one of the most potent teratogens in common use. Etretinate is associated with severe anomalies similar to those with isotretinoin 但这些都是口服跟外用的retinoids 所以看来可以建议全部送分呢(笑) 另外再附上另外一本写的 Gabbe: Obstetrics: Normal and Problem Pregnancies, 5th ed. Vitamin A There is no evidence that vitamin A itself in normal doses is teratogenic, nor is betacarotene. The levels in prenatal vitamins (5,000 IU/day orally) have not been associated with any documented risk. Eighteen cases of birth defects have been reported after exposure to levels of 25,000 IU of vitamin A or greater during pregnancy. Vitamin A in doses greater than 10,000 IU/day was shown to increase the risk of malformations in one study but not in another. 它支持高剂量vitamin K会致畸胎的reference是这篇 Teratogenicity of High Vitamin A Intake N Engl J Med 1995; 333:1369-1373 http://www.nejm.org/doi/full/10.1056/NEJM199511233332101#articleTop 而且里面提到占比例最高的畸胎其实是cranial-neural-crest origin 也不是答案选的limb malformation 搞了半天还是搞不懂出题老师的reference从哪来的.... --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 211.74.211.22 ※ 编辑: Dilberth 来自: 211.74.211.22 (08/04 14:19)