Vivid dreams are common all throughout pregnancy, according to WebMD. During the first trimester, dreams contain subject matter that mimics the mother's hopes and fears about the child she is carrying. Dreams about fertility and water are common during early pregnancy.
Many women dream about gardens, fruits and flowers during early pregnancy. It is also common for women to dream about water and swimming during the first few weeks of pregnancy as the uterus fills with amniotic fluid. A newly pregnant woman may dream of a fetus floating in water or fish swimming in water. She may also dream of herself swimming in water as a way of identifying with her unborn child, according to WebMD.