Go to doctor's appointments. Read everything you can about pregnancy, labor and delivery and parenting. Be in the delivery room. The earlier a husband gets involved, the better the couple will be able to maintain intimacy and a sense of continuity in their relationship. Both fathers and mothers should also start thinking about how having a baby will affect their lives.
Couples often have a hard time making the transition into parenthood.
Too much attention is paid to the event of childbirth itself and not to what will happen after. Parenthood is not an event, it's a lifelong process.