(LifeWire) -- You want to go out for drinks and complain about your new boss, but your friend with kids is too tired, even if she could line up a babysitter. She'd rather you come with her to the playground on Saturday morning so she can vent about her sleepless nights and flabby stomach.
Friends know when to speak up and when to be quiet.
Kaamna Dhawan knows all about that. "In many cases, when work friends have a baby, I lose a happy-hour buddy," says Dhawan, who runs a networking Web site called WomenCo.com in San Francisco. "I find that they are so strapped between baby and work that they have no time for themselves -- and therefore their friends."
When a friend has kids, priorities change, spontaneity goes out the window and the relationship is often strained -- but it doesn't have to mean the friendship is over. Here's how to make it work.
Understand friendship will change
First, the friend without kids will need to be understanding and flexible, says psychotherapist Jeanne Safer, author of "Beyond Motherhood: Choosing a Life Without Children."
"Couples without children have to know that -- for the early years, at least -- their friends will simply be less available and preoccupied," Safer says. "If it's a real friendship, that will change over time."
As the kids get older, parents often have more time to devote to the friendship, and teenagers themselves can become part of the relationship.
The sudden differences in lifestyle also can become sources of envy. Many parents at least occasionally pine for the freedom their childless friends enjoy to sleep in on weekends, travel at a moment's notice and stay out late, not to mention having more disposable income. On the other hand, those without kids may secretly covet the powerful parent-child bond.
"I am envious of the complete contentment that parents seem to have when they are around their young children," Dhawan says. "Nothing else matters. All the frivolous things that seem to preoccupy us, like looks, money and power, seem to take their rightful place in the backseat."
For women, friendships usually work better if both parties are open and matter-of-fact about these differences, says psychologist Carol Ummel Lindquist, author of "Happily Married With Kids: It's Not Just a Fairy Tale." Men, on the other hand, are often more comfortable if the differences are assumed to be understood, and they instead focus on topics of mutual interest.
Know when to put a sock in it
Emma Murphy, a New York public relations executive and married mother of two, realizes her childless friends aren't interested in talk about poop, schools or other parenting topics. But she says most do seem genuinely interested in her weekly catalog of funny stories.
At least, she thinks they are.
"In general, couples with children tend to spend much more time talking about them than their childless friends would prefer," says Safer. "Unless the friend is close to the child, it should be severely limited."
Couples without kids have to watch what they say, too. Alexandra Wills, an ethnographer in Columbus, Ohio, says she bites her tongue when discussing certain topics with friends who have children.
"It can be a challenge, especially when I don't think a friend's husband is pulling his weight with the kids, but I don't think anyone appreciates child-rearing advice from someone who doesn't even have kids," Wills says.
It's that balance in any friendship of knowing when to speak up and when not to.
Focus on the friendship
Safer says the friend with children needs to set limits for them -- not bringing children uninvited to parties, for example, or not letting them interrupt a phone conversation.
"One of the biggest, but frequently unvoiced, complaints of childless couples is that their friends with children don't set appropriate boundaries with their kids, and allow them to intrude," Safer says.
Spouses can help by encouraging their partners to have some personal time with friends without the kids tagging along, which experts say is beneficial to the marriage as well.
Friendships usually work best, Lindquist says, when the childless person takes an interest in the kids (or at least in hearing about them) and isn't too demanding of the new parent's time.
Wills agrees: "Being a good friend is trying to be supportive no matter what and enjoying the time we have together, even if it is just late-night trips to Target after the babies are asleep." E-mail to a friend
LifeWire provides original and syndicated lifestyle content to Web publishers. Heidi Sarna is a Singapore-based freelancer who has written about everything under the sun.