As much time as most women spend trying to keep from getting pregnant throughout their lives, it sometimes seems that for any woman who is sexually active, pregnancy is the default condition.

Pregnancy sneaks up on millions of women every month: pregnancy has been known to occur during one’s period, while still nursing an infant, when a partner has had a vasectomy, and when women are on the Pill. Hormones, sponges, creams, foams and various latex and non-latex products have been pressed into use by women who aren’t at a stage in life where they want children. It’s only when we start wanting to have children that we learn that pregnancy sometimes takes as much planning as childlessness did before.