Stages of pregnancy: Introduction This series aims to introduce you to the changes taking place inside a pregnant woman’s growing uterus, some of the changes that pregnant women may experience during pregnancy, and routine doctor appointments. The series is headed by gestational age, which refers to the number of weeks since the pregnant woman’s last menstrual period (LMP).

For more information, see Stages of Pregnancy: Introduction.

Week 1: The last menstrual period

Stages of pregnancy: Week 1 Week 1 of the 40 weeks of gestation begins with the last menstrual period. The menstrual cycle has two components: the ovarian cycle and the uterine cycle. Both of these components are coordinated by the hormonal changes taking place within the body. They start and end with the menstrual period, and function together to allow pregnancy to occur.

For more information, see 1 Week Pregnant: The Last Menstrual Period.

Week 2: Ovulation

Gestational Week 2 If you are planning to fall pregnant, the best time to have intercourse is around the period of ovulation. Ovulation refers to the release of the egg from the ovary, and occurs at the end of week 2 of the menstrual cycle.

For more information, see 2 Weeks Pregnant: Ovulation.

Week 3: Beginning of human development

Gestational Week 3 By week 3, the uterus has finished regenerating and is now entering the secretory phase, which will provide the ideal environment for implantation (embedding of the fertilised egg into the uterus) should fertilisation occur.

For more information, see 3 Weeks Pregnant: The Beginning of Human Development.

More information

For more information about pregnancy, including preconception advice, stages of pregnancy, investigations, complications, living with pregnancy and birth, see