Having morning sickness, nausea or vomiting during a pregnancy is common condition in many women. Based on information from the University of Maryland Medical Center, approximately 90 percent of pregnant women, experience nausea, while only 10 percent of the pregnant women will have vomiting. Morning sickness can affect a woman at any time of the day. Although there is no medicine that is approved to treat it, a natural remedy for morning sickness can be effective at relieving the problem. Also, it is important for the woman to choose the right time to take the prenatal vitamins. This is true because some women experience morning sickness immediately after they take their prenatal vitamins, especially on an empty stomach. Therefore, it will be best to avoid taking these vitamins in the morning. The best time is at dinnertime with food. If the woman continues to experience discomfort, switching brands may help with the problem.