Trimesters

• Trimesters of pregnancy

  First: 

  All tissues, organs, and organ systems begin development

  Second:

  Period of rapid growth, heartbeat is heard, bone replaces cartilage, hair begins to grow, and the mother can now feel the fetus move

  Third:

  The fetus continues to grow rapidly, fat begins to accumulate, the organ systems mature, the fetus can now regulate its own body temp., the fetus now responds to sound