4th week is the most important stage for your baby’s internal development. So, if you are having bad habits, then change them immediately. Quit smoking and avoid drinking alcohol. Avoid medications that can affect your baby.
Do proper rest.
Go for a regular check-up.
Consult with your family and friends. They will help you go through the emotional, hormonal, and physical changes during this period. Having a strong family support system may benefit you and your partner, especially if this is your first pregnancy.
Exercise helps to maintain good cardiovascular health. So, do some exercises.
This is a study on ‘Neglected symptoms of heart failure presented as peripartum cardiomyopathy: a case of maternal near-miss’. https://goo.gl/7b4E5H