Pregnancy is a very high risk time for abuse. Most survivors who are killed by their partners are killed either when they are leaving the relationship or when they are pregnant. Many primary aggressors wish to make their partners pregnant because it increases the survivors dependency, commitment and isolation. However, pregnancy seems to activate jealousy and betrayal-oriented attachment. If sex is interrupted or changed, that can lead to escalation because many primary aggressors demand sex as proof of loyalty.
If a relationship ends, custody disputes and child support problems are almost certain if a primary aggressor is the other parent. Primary aggression works with the belief, if only unconcious, that a woman does not have the right to end the relationship. Having a child together, unfortunately, makes that belief nearly true.