Around the beginning of week three (or the very end of week two), you ovulate -- one of your ovaries releases an egg into a fallopian tube. If, on the way to your uterus, that egg meets a suitable sperm, fertilization occurs, and you've conceived. Genetics established, gender determined.
The single cell that is your fertilized egg, or zygote, immediately begins dividing to become a multiple-celled blastocyst, and by the end of week three, that blastocyst is a full-on bundle of cells that could still fit on the head of a pin but is huge compared to the zygote it was just days ago.
All the while, that blastocyst is traveling through the fallopian tube, heading for the warm, squishy uterus that will be its home for many months. Once there, it starts implanting in the uterine wall.
Also this week:
- Amniotic fluid is beginning to surround the blastocyst.
- Your body begins producing pregnancy-level estrogen and progesterone (yay, nausea!).
All this organized chaos is happening inside mom, but that doesn't mean partners are out of the game …