They may be royal, but even Will and Kate have likely considered how a child will affect the family finances.
In the U.S., a baby costs a middle-income family nearly $235,000 to raise to age 17, according to a 2011 Department of Agriculture report on the cost of raising a child.
That's about 154,000 pounds, although the duke and duchess of Cambridge can hardly be considered middle income - especially given Will's $15 million (10 million pounds) legacy inherited from Queen Elizabeth II when he turned 30 last year.
"Basically, (the royal couple) do the same as you or I (when planning for a baby). They just have a bit more money to do it with," says Dickie Arbiter, a former Buckingham Palace spokesman.
Will and Kate will still be buying diapers and baby food like everyone else. And it's the day-to-day expenses once the baby arrives that put a dent in a family's finances if they aren't planned for, says Nat Sillin, head of U.S. financial education for Visa.
"A common pitfall is not having a strong enough understanding of all the costs," Sillin says. "People always consider the cost of paying for college or the cost of a child's health care. It's also important to remember how quickly the cost of diapers can add up - or formula."
Visa's personal-finance education website offers a budgeting calculator for a baby, allowing you to fill in figures for one-time and recurring expenses and then computing the total.
Of course, most parents aren't planning or can't afford the cost of educating their children at famed British boarding school Eton, where tuition runs nearly $50,000 a year.
But even if private school isn't part of the game plan and your newborn won't have a title, there is financial planning every parent can take when a baby is on the way, including:
• Estate planning. Update the documents, says Frank Fantozzi, CEO of Cleveland-based financial management company Planned Financial Services. Name a legal guardian for your child as well as a financial trustee. They don't have to be the same person, Fantozzi says, and it's a good idea to ask before naming someone to either of these roles.
• Retirement savings, life insurance. While your spouse or partner is likely your primary beneficiary, you should add your children as "contingent beneficiaries," Fantozzi says. If both parents die, this will ensure the accounts transfer to the kids.
• Homeowner's insurance. Update the policy to cover upgrades you may have made for a child, says Janet Ruiz, spokeswoman for Fireman's Fund Insurance. The nursery renovation at Kensington Palace for Kate and Will's baby cost $1.5 million. If you're making those kinds of additions to your home (or anything more than $5,000), make sure your policy covers it, Ruiz says.
• Auto insurance. Kids may mean the oft-reluctant switch to life with a mini van, but that could also mean discounts on your policy, Ruiz says. "Safer is usually cheaper," she says. So check with your provider if you're changing to a more family-friendly vehicle.
• Paying for college. Start saving. Tuition has been steadily increasing, and two-thirds of college students and graduates have loan debt. Get an early start by setting aside money in your own account before the child is born, Fantozzi says. Then consider setting up a 529 savings plan or other similar account after the baby arrives.
• Life insurance. It isn't necessary for most people, Fantozzi says, but if your family has a history of certain medical risks, buying life insurance when your child is young can help later. There are plans that offer the option to purchase additional coverage later "without having to prove insurability," Fantozzi says, possibly avoiding higher rates or coverage denial.
• Possible divorce. Even Will's parents went through a marital split, and it was ripe with financial disagreements. Any assets you leave your child could potentially go to an ex-spouse in a divorce settlement. To prevent that you can set up a trust that names your child as a beneficiary but not an owner of the asset, Fantozzi says. Then the inheritance isn't up for grabs in any split of marital assets.