A typical pregnancy last for 280 days, counting from the last day of your period. Which is roughly 40 weeks. Those weeks are divided into three trimesters. Trimesters last about 12-13 weeks.
Many changes takes place when you are pregnant, from morning sickness to your water breaking. Different things take place in each trimester. Let's take a closer look at the three trimesters.
Your first trimester is 0-13 weeks.
In this trimester you no longer have a period and your breast start to get larger. You may have to urinate more than usual. This trimester is usually when you have the most morning sickness. You will begin to crave certain foods. In this trimester you may experience heartburn and constipation. In the first trimester your baby's heart starts beating and the lungs start to develop. In this trimester your baby's eyes, ears, arms, legs, fingers, and toes form. Your baby starts to grow hair and develop genitals in this trimester.
Your second trimester is week 14 to week 28.
There are a lot of changes in this trimester. This trimester marks the middle of your pregnancy. In this trimester your tummy starts to expand and your appetite increases. Between weeks 16 and 20 you will start to feel your baby move and kick. You may start getting brown patches on your face in this trimester. Your feet and ankles will probably begin to swell in this trimester. The skin around your nipples will start to turn a dark brown. In this trimester your baby will start to grow quickly from now until birth. Your baby's organs will develop further and start working. Your baby's eyelashes, fingernails, and eyebrows will begin to form.Your baby will begin kicking in this trimester. Your baby can pass urine, hear, swallow, and suck his or her thumb. At the end of this trimester your uterus will be near your rib cage.
Your third trimester is week 29 to week 40.
This is your last trimester. In this trimester you will have to urinate a lot more than usual. This is because your baby has dropped and puts extra pressure on your bladder. Your breast will start to leak at anytime during this trimester. Your navel may start to stick out. In this trimester you will probably start to have contractions and your cervix will start to thin out and you will start to dilate. Your baby will kick and stretch out in this trimester. Since your baby's major developments are finished, he or she will start to gain weight quickly. Your baby usually turns in to a head down position for birth.
At the end of your first trimester your baby is about 2 1/2 inches long and weighs about three ounces. That is about the length of a q-tip. At the end of your second trimester your baby weighs about two to three pounds and is about 14 inches long. When your baby is born, he or she will weigh about 6-9 pounds and about 18 - 22 inches long.