Long before you hear the first heartbeat or see the first sonogram, naming your baby might be what makes the pregnancy - and the person growing inside you - feel real. But of the approximately 5,000 first names in common use in the U.S. and the infinite number you could invent, which will you give your mystery child?

Naming is your first big parenting choice - welcome to 18 more years of personality-molding decisions. Day care or home care, TV or none, bangs or no bangs? These are tough choices. But bangs grow back, while names are (or are meant to be) permanent.

Luckily you have nine months to find the perfect moniker - one that sounds good when you coo it, yell it or hear it intoned at a graduation ceremony. And one that will fit a 50-year-old with a beer belly as well as it does a sweet newborn. To help you get started, here are some Do's and Don'ts. Happy naming!

Do

• Consider what your child’s initials will spell. Because we failed to think about her hyphenated last name, my daughter’s initials are PMS. So far her wild mood swings have lasted six years.

• Try alternative spellings. Changing an "i" or an "e" or doubling a letter can breathe fresh air into an overused name. In 2007, Hailey was the 23rd most popular girls' name in the U.S., while Haley was 76th and Hallie was 523rd. The downside? You’ll be hard pressed to find a “Hallie” key chain.

• Think about how the first and last names will sound together. Alliteration (Jaiden Jenkins or Emma Evans) can be silly, and rhyming names are generally best for storybook characters (Amelia Bedelia). If the last name ends with a vowel, the first name probably shouldn’t if you want to avoid one long mishmash. Short first names sound good with longer last names and vice versa, but a long first-and-last name pairing can be a mouthful - just say Engelbert Humperdinck!

• Take a stroll through your local graveyard or visit a historical-cemetery website if you like old names. You might find some doozies that have yet to be discovered and popularized. We spotted Roggar, Emey and Emeline during a quick online trip.

• Keep your chosen name a secret if you're a pushover and have meddling friends or family. And if your mother is particularly opinionated, don’t ask her advice - when she inquires, just tell her you're still undecided. Better to fib than end up with a name you didn't want. Can't lie? Feign a contraction to distract her.

• Remember that you can make people happy with a well chosen middle name. Need to honor a relative? This is a good place to do it. Appease your spouse? You didn't go for his suggestion of Hubert for first name, but you can tolerate it as the H. in the middle. An unusual name might even be the pinch hitter your child chooses for himself during the probably inevitable phase when he doesn’t like the first name you gave him.

• Accept that it's perfectly valid to veto a name because that annoying girl in third grade always had her finger up her nose and you will forever associate Elizabeths with nose-pickers. And honor your partner's preferences, too - your favorite name might bring to mind a creepy babysitter or childhood pet.

• Pore over the most and least popular names by year and by state on the Social Security Administration Web site. It’s the pregnant woman’s equivalent of online stock watching. For a more updated, more specific (if less complete) version - it drills down to hospital level - check Our365's Baby Namescape.

• Check out some name books. One fun read is “Beyond Jennifer & Jason, Madison & Montana: What to Name Your Baby Now.” It has handy categories such as “So Far In, They’re Out” (which might break your heart) and “So Far Out They’ll Probably Always Be Out” (think: Gail, Barry).

Don’t

• Feel pressured to register your baby's name before you leave the hospital if you're undecided, and do not assume you can just change the name later if you change your mind. Meg Ryan was mercilessly mocked when she told Oprah Winfrey, “I already had to change her name - I thought she was Charlotte and she s just not. She’s a Daisy.” Feel free to wait a few days post-birth to get to know your baby (hospitals will pressure you to decide on a name before going home, but actual state deadlines vary). Trust us, your little one won't wind up in therapy talking about how her parents left her nameless for almost a week.