When an egg is fertilized, the rapid release of zinc creates a spark. Jillian Bell · CBC News · Posted: Apr 27, 2016 5:00 AM EDT | Last Updated: April 27, 2016.

In fact, most pregnancy loss happens before the fertilized egg implants. Defining exactly when a pregnancy begins is a hot topic in some state legislatures and U.S. courts at the moment.

If the egg is fertilized, the corpus luteum remains intact and continues to release progesterone for the first 12 weeks of pregnancy. In these 12 weeks, the placenta develops along with the fetus ...