What to do if your belly is not big at four months of pregnancy (Frequently Asked Questions During Pregnancy) During pregnancy, every woman will experience the experience of her belly gradually getting bigger. However, some pregnant women have a small belly when they are four months pregnant, which makes them feel worried and uneasy. This is common, but it doesn\’t mean something is wrong. This article will explain why your belly is not big during the fourth month of pregnancy and give you some tips to help pregnant women. Reason 1: Fetal size When pregnant women are four months pregnant, their belly is not very big yet. This is normal. In fact, in my arms