How does fertilization occur?
common.months_ago
Explanation of how pregnancy begins and develops: During intercourse, sperm travel through the uterus into the fallopian tube, where one may meet an egg that has ovulated from the ovary. After the sperm fertilizes the egg in the tube, the embryo develops from a fertilized egg to day-3 and then day-5 (blastocyst) stages; the blastocyst has two parts—one that forms the baby and one that forms the placenta. Around day 5, the embryo hatches from its shell, implants in the uterus, becomes a fetus, and ultimately a baby; these basics underpin related tests and treatments.
pregnancy: The condition of carrying a developing embryo or fetus in the uterus.
intercourse: Sexual activity that can lead to sperm entering the reproductive tract to fertilize an egg.
sperm: The male reproductive cell that can fertilize an egg.
uterus: The womb; the organ where an embryo implants and a pregnancy grows.
fallopian tube: The tube connecting the ovary to the uterus; where the egg and sperm usually meet and fertilization occurs.
egg: The female reproductive cell (ovum) that can be fertilized by sperm.
ovulated: Released an egg from the ovary.
ovary: The organ that stores and releases eggs.
fertilized egg: An egg after it has merged with sperm; the first stage of an embryo.
embryo: The early stage of human development after fertilization and before becoming a fetus.
blastocyst: A day-5 embryo with two parts: one that will form the baby and one that will form the placenta.
placenta: The organ that develops to provide oxygen and nutrients to the baby during pregnancy.
implant: When the embryo attaches in the uterus to start a pregnancy.
fetus: The stage of development after the embryo stage and before birth.