Why do pregnant women get confusing guidance about alcohol?

How much alcohol can cause fetal alcohol spectrum disorder, a difficult to diagnose condition, sometimes called an "invisible disability"? Doctors don't know. While official guidelines say no amount of alcohol is safe to drink during pregnancy, women often receive mixed signals, even from their own physicians. Amna Nawaz reports. Find more from PBS NewsHour at https://www.pbs.org/newshour Subscribe to our YouTube channel: https://bit.ly/2HfsCD6 Follow us: Facebook: http://www.pbs.org/newshour Twitter:   / newshour   Instagram:   / newshour   Snapchat: @pbsnews Subscribe: PBS NewsHour podcasts: https://www.pbs.org/newshour/podcasts Newsletters: https://www.pbs.org/newshour/subscribe