At week 13, the pressure on the bladder begins to subside as the uterus grows up and out of the pelvic bones. As the waistline thickens and the pressure is relieved from the bladder, one may begin to experience abdominal pains. One may also begin to experience round ligament pain as the ligaments that support the uterus stretch and pull. One may still be experiencing heartburn in the chest and throat. The breasts are still growing and are probably extremely sensitive due to the colostrum they are producing. The breasts are preparing for lactation and the mammary ducts are growing larger.


The baby starts producing meconium. This black, sticky substance will accumulate in baby’s bowels. Fingerprints are forming on the baby’s tiny fingertips.

Making colostrum, cramping are common body changes during this week. The size of the baby is about the size of a peapod, length is 3 inches and weighs ¾ ounce.