Fetal Development

Pregnancy is one of the most exciting times in a woman’s life, and in a couple’s relationship. Being able to nurture and nourish a growing baby is a gift that should be cherished and held dear. The development of your unborn baby is a fascinating process that never ceases to amaze.

Your baby does most of her development in the first three months. Did you know that most of your baby’s organs and structures are fully formed by the end of the first trimester? This section provides information about the normal development of the unborn baby during pregnancy.

Growth and Development Highlights
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The Pregnancy & Babies resource centre counts the weeks of pregnancy starting with the date of the beginning of the woman's last menstrual period, which is estimated to be about two weeks before the date of conception. Therefore, the countdown of fetal development begins at week three after the beginning of the woman's last menstrual period. When counted this way, pregnancy will last a total of 40 weeks. 

Pregnancy Timeline
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Nicolette Caccia, MEd, MD, FRCSC

Rory Windrim, MB, MSc, FRCSC