For those impatient aspiring dads who can't wait longer to find out, here are the eight top early pregnancy symptoms that they should look out for:

Darkening of the nipples, or more precisely the skin around the nipples (called areola), could be one of the early pregnancy symptoms. However, it could also be a sign of hormonal imbalance, so hold on before you jump to the wrong conclusions.

A sudden and inexplicable craving for certain foods is another potential, though not always reliable, sign of pregnancy. So if you find your spouse midnight snacking on a chili cheeseburger for the nth time this week, you have good reason to keep your fingers crossed.

Pregnancy will cause hormonal changes in your spouse's body that may lead to headaches. A sudden onset of headaches, especially if she never had them before, could be an early pregnancy symptom. Bouts of dizziness, due to a drop in her blood pressure, may be another early sign that she is expecting.

During pregnancy, your spouse's body will release the hormone human chorionic gonadotropin (hCG) that induces increased urination. Her frequent bathroom visits may actually be something to be happy about.

Frequent mood swings and crankiness are yet another , as you will soon find out. While this may not be the happiest part of the pregnancy where you are concerned, at least you can blame it on those raging hormones.

If your spouse complains that her breasts seem sore or tender when touched, that's another sign that you may soon become a dad.

Nausea and vomiting, starting few weeks after conception or even earlier, may be one of the most common early symptoms of pregnancy. The popular term '' is a misnomer though, as the symptoms are felt pretty much throughout the day.

A missed period, especially if your spouse is generally regular with them, may be a very likely indication of pregnancy. However, only a pregnancy test will confirm this for sure.