Concept: Pregnancy: • The period during which a fetus develops inside a woman's womb or uterus is known as pregnancy. • When counting from the last menstrual cycle through delivery, a pregnancy typically lasts about 40 weeks or just over 9 months. • Pregnancy is divided into three trimesters, as described by healthcare professionals. Explanation: First trimesters: • The first trimester lasts from week one to week twelve. • The fetus grows from a fertilised ovum to about 6 cm long at 12 weeks during the first trimester. • The baby's heart begins to beat around the end of the first trimester. • The brain, stomach, and intestines are grown during this time as well. Thus, the first three months of pregnancy are called the first trimesters. Related Concepts: Second trimester: • From week 13 through the end of week 26, the second trimester is comprised. • The developing foetus kicks moves and has the ability to turn. • The ears have shifted from the neck to the sides of the head, and the eyes have progressively moved to the front of the face. Third trimester: • Week 27 of the pregnancy till the end of the third trimester. • The lungs are still developing, and the foetus is moving toward a head-down position. • The foetus is roughly 19 to 21 inches long and weighs 6 to 9 pounds on average at the end of the third trimester.