This article is the second in a series called the biological basis of child health. It considers the period of development from fertilisation to birth, outlining the three stages of prenatal development - the germinal, embryonic and fetal stages. The article details how tissues and organs typically develop at each stage, and explains how and when deviations in development and congenital anomalies are likely to occur. It also describes some of the common congenital anomalies, their potential effects and their detection before or after birth. Information is also provided about the delivery of full-term infants, including the stages of labour
