From the first day of your last normal period until the delivery, a full-term pregnancy lasts about 40 weeks. These nine months can be roughly broken down into three trimesters, each of which is characterized by a unique set of physical developments. The following guide, in addition to guidance from an obstetrics physician, should help you determine what to expect.  

The 3 Stages of Pregnancy 

First Trimester (Week 1 – Week 12) 

Dramatic hormonal changes occur during the first trimester. It's common to experience a few symptoms during this period, which could include morning sickness and food aversion. Eat small meals throughout the day, and talk with your doctor if nausea becomes disruptive or you start losing weight.

Most women say symptoms are the most severe during the first trimester. You might even notice some of these changes happen before you miss a period or realize that you’re pregnant. 

Second Trimester (Week 13 – Week 28) 

During the second trimester, your baby bump will become more pronounced. You might start to feel your baby’s movements, called quickening, at any point after the 13th week.  

Some women experience back pain during their second trimester because of the additional weight they carry in the abdomen. If this occurs, try wearing a brace to reduce muscle strain. 

At this stage in your pregnancy, your doctor can try to see the external sex organs and tell you the baby’s gender. The second trimester is also characterized by significant growth—the fetus grows from about 3 inches long to about 12 inches long. 

Third Trimester (Week 29 – Week 40) 

As your body prepares for labor, the baby will move lower in your abdomen and your cervix will start to thin and open. Once your cervix opens to about 10 centimeters, you’ll be ready to go into labor. Sometimes this process, called effacement and dilation, will occur gradually over the course of several weeks. For other women, the process can occur seemingly overnight.

Braxton Hicks contractions, or false labor, are also thought to play a role in softening the cervix and preparing the muscles for childbirth. A Braxton Hicks contraction can feel like a mild menstrual cramp and might occur when you’re active or have a fully distended bladder. These false labor contractions happen at irregular intervals and don’t increase in severity. They should dissipate over time and might improve by going to the bathroom or drinking water. 

Every pregnancy is different. If you have questions about your experience, the obstetric and gynecology team at Greece OB-GYN, LLP will answer them thoroughly. Located in Rochester, NY, they’ve served women in Monroe County for over 30 years. In addition to providing prenatal care, they also offer antenatal testing and prenatal genetic screening. To learn more about their obstetric care services, visit their website or call (585) 225-6680 to schedule an appointment. After-hour appointments are available.