One of the most challenging things for an expectant dad to anticipate is the start of labor and delivery. There is no alarm or schedule that tells you and your partner the exact moment that "real" labor begins.
So how can we know?
The pain will start in Mom's back and move to her abdomen—or vice versa—and the contractions will steadily increase in strength.
If your partner walks around or shifts positions and the contractions keep coming, that's a clue they're actual contractions and not Braxton-Hicks (aka "false" contractions)contractions. Feeling nauseous, vomiting, or having diarrhea can also be signs that stage 1, phase 1 of labor has started.
As soon as you suspect that genuine stage 1 labor has begun, start timing the length of each contraction, along with the amount of time between the end of one contraction and the start of the next.
Then call the doctor or hospital and explain your partner's symptoms. They'll ask you (or her) some questions to help determine where she is in the process. They'll also tell you whether to head to the hospital now.
By the time your partner is transitioning from stage 1, phase 2 to stage 1, phase 3, you should be at the hospital (or at least on your way there), because she’s entering the most intense part of labor.
If you see vaginal bleeding or any fluid coming out of the vagina, call the doctor. And get moving if her amniotic sac has ruptured (a.k.a. her water breaks). That means the baby no longer has the protection of the sac, and a physician has to decide on what steps to take, such as inducing labor.
Adapted from Idiot's Guides: Pregnancy for Dads by Joe Kelly, © 2014, Alpha Books.