Parents who opt to take a sabbatical from their jobs and stay at home will face many hidden opportunity costs such as lost wage growth and retirement savings.

A research report conducted by the Center for American Progress, a non-profit organization based in Washington, D.C., delves into other financial ramifications of leaving the workforce in addition to a loss of income. Many parents focus on the rising costs of childcare and neglect to probe into the total cost of leaving their jobs or careers, said Katie Hamm, senior director of early childhood policy and a co-author of the study.

For every year that parents elect to take one year off, they "stand to lose three to four times of their annual salary," in their lifetime income, she said.

The average age for a woman to have her first child is 26 years old, and the median salary of women ages 21 to 31 years old is $30,253, according Hamm, Michael Madowitz and Alex Rowell who co-authored the report. By choosing to stay at home for only five years, a woman will lose $467,000 during her career and reduce her lifetime earnings by 19%.

"You see the impact compound over your career," she said.

In the same scenario, a 26-year-old man generates a median income of $33,278 annually and, by choosing to stay at home, reduces his lifetime earnings by 22% or $596,000 because of the gender wage gap.

An interactive tool developed by the Center for American Progress can help parents calculate their losses based on gender, age, salary and the amount of time they plan to stay out of the workforce.

The annual cost for a family with a four-year old and an infant is almost $18,000, leaving many parents to shell out about 30% of their salary for childcare, said the Center for American Progress. While a large majority of parents focus on spending $10,000 to $20,000 annually for childcare costs, they fail to consider other benefits such as matching contributions to their retirement accounts.

"This report shows the hidden costs of having children and shows the full picture of the childcare crisis," Hamm said. "It is good for parents to have all the information of childcare costs and compare that to what they lose if they leave the workforce. This is what is often missing from the conversation."

Parents are often faced with a Catch-22 on either spending a large chunk of their income on childcare or losing the potential for salary raises and other financial benefits such as lower health insurance premiums and deductibles.

Low-income families encounter even more dilemmas, because they often do not earn enough money even for the least expensive child care, she said. Only one out of six families qualifies for federal programs that are not well-funded, allocating a maximum of $5,000 annually for parents.

"If you only earn $30,000, you can not come up with the $10,000 to pay for childcare," Hamm said. "If a mother leaves the workforce, she will pay a huge premium for her choice. There needs to be support to develop another solution for families so they have choices."

Ways to Increase Your Retirement Savings

Parents who are agonizing over how they can ramp up their retirement savings should start by investing their next raise before they leave the workforce. Forgo your latest raise, since you are already accustomed to living on a lower amount and have the increase automatically diverted it into your 401(k) or IRA.

"Act as if you didn't receive a raise and invest the raise for retirement," said Robert Johnson, president of The American College of Financial Services in Bryn Mawr, Pa. "You won't even miss the money. If you simply invest your first raise and continue to have that same amount taken out of your paycheck and invested each pay period, you will accumulate significant wealth."

Parents who return to the workforce can implement another strategy to boost their retirement funds. Increase your contributions every year by the percentage of your raise, which means if you receive a 3% raise, increase your contribution by 3%, said Daniel Keady, a senior director and CFP for TIAA, the N.Y.-based financial services provider.

Increase your contributions by raising the amount 1% each year whether it is a 401(k) or IRA, said Jim Wright, a portfolio manager on Covestor, the online investing marketplace, and chief investment officer of Harvest Financial Partners, a registered investment advisor in Paoli, Pa. A 25-year-old earning $25,000 per year would add $250 for a 1% increase in his contributions. When you turn 65, the additional contribution will be worth $2,500 if you earn 6% a year.

Rebalance your portfolio at least once a year, but do not focus on short-term losses sustained from volatility in the market, said Spencer Betts, a CFP at Bickling Financial Services in Lexington, Mass.

"Many people set up their asset allocation and never make a change or at least rebalance to the original asset allocation," he said.

Opt For More Risk

Too many investors remain fearful of losing money because of the losses they sustained during the Great Recession. Although the stock market has rebounded, a large percentage of portfolios are still too conservative and generating much lower yields, because they are not taking enough risk, Johnson said. Although many of them are Millennials and Gen X-ers who have several decades until they retire, they are still opting for "low risk, low return assets," he said.

The returns on large capitalization stocks have historically beaten bonds, said Johnson. A diversified portfolio of large capitalization stocks returned 11.4% annually from 1950 through 2014 while long-term government bonds returned 6.2%.

Invest Often

Adjust the amount of money that is withheld from each paycheck and allocate those funds for a retirement account, said J.J. Montanaro, a certified financial planner at USAA, a San Antonio-based financial institution.

While the amount of interest accumulated from credit card and student loan debt hinders the amount of money an individual can save, even investing a small amount each month boosts returns. Investing at age 25 means investors could receive greater returns. A 25-year-old who allocates $200 into a retirement account every month earning 10% will have accumulated $1.264 million at 65, said Johnson. That same investor who waits ten years and starts saving at age 35 will only have amassed $452,000 by age 65.