  
Within 24 hours after fertilization, the egg that will become your baby rapidly divides into many cells. All this happens in the womb, or uterus. By the eighth week of pregnancy, the embryo has developed into a fetus, with all of its organs in place. There are about 40 weeks, or 9 months. to a typical pregnancy. These weeks are divided into three trimesters.  1. The First Trimester: The first trimester is the three month period from conception to 12 weeks. The baby develops from a group of cells into a fetus that is starting to have a baby’s features. During this first trimester, the amniotic sac and placenta develop. The placenta provides oxygen and nutrients to the growing baby, and removes waste products from the baby's blood. The placenta attaches to the wall of the uterus, and the baby's umbilical cord arises from it. At the end of the first three months, the baby is fully formed. All the organs and limbs are present and will continue to develop to become functional. The baby’s circulatory and urinary systems are also working, and the liver produces bile. Since the baby has undergone its most critical development, the chance of miscarriage drops considerably after three months. 2. The Second Trimester: The second trimester, the three month period from the fourth through sixth month, is often seen as the best part of the pregnancy. By this time, any morning sickness the mother has experienced is probably gone, and the discomfort of early pregnancy is lessening. The baby is starting to develop facial features. In this trimester, movement can be felt as the baby flips and turns in the uterus. If born prematurely, the baby may survive after the 23rd week, with intensive care. 3. The Third Trimester: During the third trimester, the three month period from the seventh through ninth month, the baby gains weight quickly, adding body fat that will help after birth. The baby's brain is developing rapidly, and it can see and hear. The baby's reflexes coordinate so he or she can blink, close the eyes, turn the head, grasp firmly, and respond to sounds, light, and touch. The baby moves less due to tight space, now that it is bigger. Near the due date, the baby’s position may have changed to prepare for birth. Ideally, the baby is head down in the uterus. The typical full-term pregnancy is 40 weeks.
There is a fascinating pregnancy app available on both Google Play and the Apple app store that is full of useful information, and will show you 3D views of what your baby looks like at any stage of its 40 week development. Highly recommended! |
