Your baby resembles a tadpole more than a human, but is growing fast. The circulatory system is beginning to form, and the tiny heart will start to beat this week. Your baby is the size of a sesame seed. Read about your pregnancy at 5 weeks.
Stores of B12 can last for up to a year. Foods high in Vitamin B12 include shellfish, liver, fish, crab, fortified soy products (tofu, soymilk), fortified cereals, red meat, low fat dairy, cheese, and eggs.
To ensure you get enough B-12, select eggs and dairy products daily. For those who don't eat eggs or dairy, look for vitamin B-12 in fortified vegan cheese, yogurt, and non-dairy drinks; fortified cereals; fortified veggie burgers and faux meats; and nutritional yeast.