Pregnancy is usually divided into trimesters, also known as trimesters. A trimester therefore means 3 months. The derivation comes from the Latin, "tri" for three and "mensis" for month. The first trimester runs from the first to the twelfth week of pregnancy (abbreviated to SSW), the second trimester covers the period from the thirteenth to the twenty-eighth SSW and the last trimester from the twenty-ninth to the fortieth SSW. We have summarised the most important information for each trimester and each week of pregnancy. You can also use the search function to quickly find the article you are looking for.