The first three months of pregnancy.

The first trimester of pregnancy is a time when many changes happen in the body quickly. Knowing the physical and emotional changes to expect can help get ready for all that's ahead.

Symptoms in the first trimester often include tender, swollen breasts; upset stomach with or without vomiting; more frequent urination; extreme tiredness; and emotional ups and downs. Food cravings and dislikes, constipation and heartburn also are common.

After the first medical appointment, most pregnant people have checkups about every four weeks. To ease an upset stomach, eat slowly and in small amounts every 1 to 2 hours. A healthy diet and exercise may provide energy and ease tiredness and constipation. If mood changes make it hard to do daily activities, talk with a healthcare professional.