I can say from experience that expectant mothers in China who are pregnant outside the allowable one-child, or the cultural demand for sons, have no options but suffer persecution from government or family. The result is fear, and any desperate decisions that come from it.
It seems completely irrational, but for these particular women or girls, the most rational decision (once pregnancy occurs) is to abandon the baby. If the government says you must pay an unpayable fine, and your family says you will be ostracized, desperation will compel what is unthinkable to those of us not faced with the same circumstances.
