The pregnant woman should eat twice?

No. Final and absolutely not.
During pregnancy, the effect of placental hormones, there is a tendency to transform the food they eat into body mass (fat). Therefore, even eating the same thing as always, the pregnant feedlot.

To be well nourished she and the baby, the future mother should only eat as usual, choosing foods rich in protein and minerals and avoiding the high caloric content. Throughout the pregnancy, will require a greater contribution of calories, but that does not mean eating for two.