During the fourth week of the first trimester a baby's organs will start forming
and it is extremely important for the mother to take care of herself and to avoid certain foods that her doctor will inform her about that have been proven to be bad for developing babies. There are a lot of other things that will be going on with your baby during the first trimester. The three sections of their brains will start dividing and their heart will begin to separate into the different chambers during the fifth week. The most important time of the baby's life while in the womb happens in the seventh week, during this time all of their main systems will be accounted for. It is a good idea to begin getting on the right track with your pregnancy during the first week and to begin getting organized. Women should find the doctor that they want to deliver their baby and they should go ahead and do research on different classes such as breathing classes that are designed for pregnant women.