Figuring out when and how to announce a pregnancy at work can be stressful, but experts say preparation is key to making it a positive experience. (Fotolia / February 18, 2014)

When Emily H. Griebel was pregnant with her first child, she was nervous about sharing the news with her boss.

"I knew he would be happy for me but I also knew it would be tough on him if I were gone for 12 weeks," says Griebel, who today runs her own marketing firm, EHG Consulting. "With my first pregnancy, I told my boss about it just minutes after a big client presentation, as we were walking back to our hotel in Manhattan. I remember stopping for a red light and practically yelling to tell him that I was having a baby."

Griebel's boss was happy to hear the news, and it led to the company experiencing a first, too: creating a maternity leave policy.

"My company had to create a maternity policy for me because no woman had ever had a baby there before me," Griebel says.

Figuring out when and how to announce a pregnancy at work can be stressful, but experts say preparation is key to making it a positive experience. Here's how to prepare to reveal your big news:

--Do your research.

The Family and Medical Leave Act requires employers to give employees up to 12 weeks of unpaid maternity or paternity leave, but these rules only apply to companies with more than 50 employees, and only for employees who have worked at the company for 12 months or more.

Even if you and your company qualify for the FMLA, other state and local laws, as well as the company's own particular policies, can apply.

"Research your company's policy on pregnancy leave as soon as you can," says Liz O'Donnell, author of "Mogul, Mom & Maid: The Balancing Act of the Modern Woman" (Bibliomotion, $24.95). "Cross-check the information in your company policy with your health insurance company -- sometimes the information conflicts."

If you're not ready to announce your pregnancy and don't want to arouse suspicion by asking questions about maternity leave, just ask your company's HR department for a copy of the employee handbook -- it should contain details about maternity leave policy.

--Figure out timing.

When is the best time to reveal your big news? Many expectant moms and dads wait until after the12-week mark, statistically when risks for miscarriage are lower, to reveal their news at large.

You may want to wait later than that to announce your pregnancy at work, or you may want to share the news even earlier. Whatever timing you're comfortable with, experts agree it's best to give your boss and coworkers as much advance notice as possible.

"As a practical matter, most employers would appreciate several months' notice so they can find a temporary replacement and make other arrangements," says Cynthia Thomas Calvert, an employment lawyer and president of Workforce 21C, a firm that consults employers about family responsibilities discrimination. "Practicality may dictate an earlier disclosure for a different reason, however. If a woman is having a difficult pregnancy, she may need to take time off for doctor's visits or because she is too ill to work, and she may need accommodations so she can continue to work."

No matter when you choose to make your announcement, make sure your boss learns about your pregnancy directly from you, and not from the office grapevine.

"The worst mistake you can make is waiting too long to share your news with your boss. If he or she finds out about your pregnancy around the office water cooler or, even worse, through your social media blasts -- we've seen it happen -- the resulting conversation will not be positive," says Katherine Wintsch, founder and CEO of The Mom Complex, a consulting firm that helps companies connect with mom employees and customers. "Your boss deserves to learn your news in person and firsthand."

--Make a plan.

Before Chris Peterson, a client trainer for a software company, told her bosses about her pregnancy, she constructed a thorough plan to present to her managers. The plan included details about projects she was currently working on, projects she works on continuously throughout the year, and suggestions on how to cover for the work she does, like automating some tasks and training coworkers on how to perform others.

"When I was ready to discuss, I scheduled a meeting with my manager, printed the plan and reviewed it with him," Peterson said. "[The managers] said it was very well thought-out and constructed. They celebrated it by throwing me a baby shower."