When you get pregnant, small changes occur in your body and in the developing fetus during a 40-week period, up until the baby is born. Knowing what is going to happen and when may help ease your mind during your pregnancy. It will also let you know when and if you should be concerned about your health or that of your baby.
Weeks 1 Through 8
During the first weeks of your pregnancy, you will most likely not even know you are pregnant. Fertilization of the egg usually occurs in the third week and during the fourth, the baby is still a small ball of cells that will split in two to form what will become the baby and the placenta. Many women experience some unpleasant symptoms, such as cramping, spotting and tenderness of their breasts starting around the fourth week. You may also experience morning sickness by the end of the eighth week.
Weeks 9 through 16
Toward the end of your first trimester, or weeks nine through 12 of your pregnancy, the embryo will begin to look like an actual baby. Around nine weeks, many embryos weigh less than an ounce and are about 1 inch long. He will have started developing a heart and other organs, as well as his muscles. He will continue to grow through the start of the second trimester and will usually be about 4 inches long by the 16th week. You may feel tired starting around the ninth week and may experience some dizzy spells around the 12th week. By the 16th week, your morning sickness should have subsided, and your skin may actually start to glow.
Weeks 17 through 24
By week 17, your baby should be able to move her joints and may have developed hearing. Around week 18, you may be able to feel her move about inside of you. If you would like, an ultrasound can tell you the baby’s gender around the 20th week. She will start to get fat deposits around week 23 and will begin to grow even more rapidly. During these eight weeks, you may notice that your legs cramp, your feet have swollen, and that your skin has darkened in certain areas. Your uterus will have swollen to the size of a soccer ball by the 24th week.
Weeks 25 Through 32
During weeks 25 and 28, you should get a glucose test to make sure you have not developed gestational diabetes. You may also be tested for anemia at this time. On the plus side, you may notice that your hair is thicker and more lustrous the before, due to pregnancy hormones. The baby is usually around 13 inches long at the start of week 25. By week 32, she may be almost 19 inches long. Her weight will have increased to 4 lbs. She will be able sleep and hiccup around week 27 and will be practicing breathing and swallowing by week 32.
Weeks 33 Through 40
Your baby will have developed fingernails by week 34. By week 36, most of his organ systems will be fully developed. By week 37, he will be considered full-term, meaning his lungs will be mature, and he could survive outside your uterus. During these final weeks, you may find it difficult to get around and may experience hip pain as your body prepares for delivery. You may start experiencing contractions around week 37. By the 40th week, your baby should be ready to make his first appearance, though don’t be surprised if he takes his time coming out.