Your stomach may start to get hard when you are pregnant, usually at around 12 to 16 weeks, depending on the baby’s development, position, and whether the uterus is contracting.
During the second or third trimester, uterine contractions may temporarily make your belly feel hard, especially across the front. These contractions are usually mild, irregular, and brief and are known as Braxton Hicks contractions.
The belly often becomes more noticeable between 16 and 20 weeks of pregnancy. How quickly it grows can vary depending on the amount of amniotic fluid, abdominal muscle tone, the baby’s development, and whether you are carrying one baby or multiples.
Closer to delivery, your belly may appear lower or slightly smaller when the baby moves down into the pelvis. Regular prenatal appointments are important to make sure the pregnancy is progressing normally and the baby is developing as expected.