How much does a baby weigh in the first 11 weeks of pregnancy?

In the first 11 weeks of pregnancy, the developing baby, known as an embryo and then a fetus, is quite small and typically weighs less than an ounce (about 0.2 to 0.3 ounces or 5 to 10 grams). By the end of the 11th week, the fetus is around 2.5 inches long. Weight can vary, but it remains minimal during this early stage of development.