There’s something about seeing a pregnant belly that makes even the most civilized people forget their manners.

In what other situation would people feel comfortable telling a woman, “You look heavy” or “Aren’t you a little old for that”?

If you’d rather not press a pregnant woman’s buttons, consider these tips from the Mommy Docs, a trio of ob-gyns who star in the television series Deliver Me, who have witnessed 15,000 deliveries and have six children between them.

Yvonne Bohn, MD, Alane Park, MD, and Allison Hill, MD, also penned The Mommy Docs’ Ultimate Guide to Pregnancy and Birth, so they know their way around a mother-to-be’s body and mind.

Read on to see common ways that people inadvertently offend expecting moms, plus things they’d prefer to hear instead.

“Are you sure you’re not having twins?”

“Every inch of me looked pregnant from six months on,” says Sarah, a mother of one. “So relatives would ask, ‘Are you sure there aren’t two in there?’ or say ‘You look like you’re about to pop!’” You wouldn’t mention extra pounds to someone who wasn’t pregnant, so why is the weight of a woman who’s expecting fair game? It’s not. “Women gain different amounts of weight in their pregnancies,” says Dr. Bohn. And pregnant women can be especially sensitive about added pounds, especially if they’re already not feeling particularly attractive. If you feel compelled to comment about a pregnant woman’s appearance, stick with something positive and vague, such as, “You look great!”

“You’re so tiny—you can barely tell you’re pregnant! That can’t be healthy.”

“I carried all in the front for both pregnancies,” says Nicole, a mother of two. “People thought they were paying me a compliment by asking, ‘Are you eating enough?’ But really, they were making me second-guess my weight, which, according to my doctor, was fine.” Again, pregnant women gain different amounts of weight, and every woman carries that weight differently. A mom-to-be who seems small to you could be perfectly healthy—and she’s probably sick of people trying to force-feed her. “Only a woman’s doctor can advise her on what’s healthy for her and her baby,” says Dr. Bohn. Even if you’re trying to make a pregnant woman feel good about herself, skip comments about her weight gain—or lack thereof.

“Are you disappointed it’s not a girl?”

Nicole also got frustrated when people would say, “It’s your second baby? You must be trying for a boy!” or ask “Are you upset it’s not another girl?” Given how awesome a pair of sisters (Venus and Serena Williams) or a bunch of boys (the Jonas brothers!) can be, it’s strange to assume parents want a boy-girl set—or prefer a child of one sex over the other. “It boggles my mind when people say stuff like this,” says Dr. Park. “Most of our patients just want a healthy baby!” The only assumption you can make about a woman who’s having a second or third baby is that she wants another child. Period.

“You’re going to breastfeed, right?”

School-teacher Beth, a mother of two, couldn’t stand people prying about her feeding plans. “My mom friends would ask if I was breastfeeding. I did, but only for eight weeks. There’s no time to pump in the three-minute break between classes—and I hated having to justify my decision.” From a health standpoint, breast is best because breast milk may protect against infections and diseases, prevent a baby from developing allergies and more. But whether or not a woman breastfeeds is a personal decision that needs no explanation. Plus, Dr. Park points out, there are circumstances (like demanding jobs) and health conditions (like not being able to produce enough breast milk) that make it difficult for a mom to breastfeed. And no woman—pregnant or otherwise—should feel obligated to share her medical files or personal history to defend her actions. “Resist the urge to give advice on breastfeeding,” urges Dr. Park. Unless, of course, you’re asked. Even then, fight the compulsion to impose your beliefs on someone else.

“Oh, you’re wide! You’re definitely having a girl!”

“A daughter steals her mother’s beauty,” Sarah’s grandmother announced. And the mailman—yes, mailman!—decided Sarah was wide for an expecting woman, and declared she was having a girl. Sarah survived comments from the peanut gallery—and gave birth to a healthy son. Despite the countless myths and wise old women in the grocery store, “there’s no proven method to predict whether a woman is carrying a boy or a girl based on the mother-to-be’s physical appearance,” confirms Dr. Hill. Besides, what feels like good fun and guessing games to you might feel an awful lot like an insult to the woman you’re passively calling unattractive or fat.

“I was back in my skinny jeans a week after giving birth.”

That’s what a neighbor told Beth when she was a week past her due date and feeling the opposite of skinny. Seeing celebrity moms looking gorgeous on the red carpet two minutes after having a baby is enough to make any mortal new mom want to run for cover. So don’t add to the pressure by bragging about your own fabulous post-baby body. “What worked for you might not work for another woman,” says Dr. Hill. For example, even though breastfeeding burns hundreds of calories, not every mom will drop pounds by nursing alone. “If you want to be supportive, avoid making comparisons,” adds Dr. Hill.

“I hope the baby gets your nose!”

“My mother-in-law loved to say this,” says Nicole. “But what if my child didn’t get my nose? Would I love him less? And did she love my husband less because of his large-ish nose?” You might think you’re complimenting an expectant mom here, but she could take those words as, “Jeez, your husband’s nose is big,” says Dr. Bohn. New parents are going to think their baby is gorgeous, even if the child arrives with Uncle Charlie’s bushy eyebrows. Instead of speculating about the baby’s looks, try something like, “New babies are the sweetest. I bet you can’t wait to meet her!”

“Did you see that show about the baby with [insert horrible disease here]?”

Beth shared a classroom with a teacher who loved to tell doomsday scenarios, always asking if she’d heard about that baby who had suffered from x, y or z. Or she’d share gems like this: “My boss’s wife’s second cousin’s former roommate died in labor! But you’ll be fine!” Any mom who’s cracked open her baby books knows there’s plenty that can go wrong in nine months and beyond. You don’t need to add to her fears by sharing horror stories—especially those you heard through the grapevine or on the Lifetime channel. “Moms worry enough on their own,” says Dr. Hill. Rather than adding to the stress, save your “Did you hear about the…?” stories for someone who’s not expecting and share happy stories or ask what the mom-to-be is most excited about.

“That must’ve been a surprise!”

When Nicole got pregnant at 23 on her honeymoon, people assumed the pregnancy was a mistake. (It wasn’t!) “Did you plan to get pregnant so soon?” a friend asked, and “That must’ve been a surprise!” a co-worker said with a wink. “The timing of a woman’s pregnancy is none of your business,” says Dr. Park. What seems “so soon” to you might be exactly the time the expecting parents intended to get pregnant. And even if the pregnancy wasn’t planned, if the parents are embracing it, you should, too. When someone offers up pregnancy news, the best possible thing you can do is share her enthusiasm.

“Aren’t you too old to have a baby?”

Conversely, Sarah, who got pregnant at 39, was constantly fielding questions related to waiting to have children, like, “Did you make your baby the old-fashioned way?” Once a woman’s pregnant, it’s not your concern how the bun got in the oven—or whether the oven’s a little on the older side. Like other expecting moms, older moms-to-be are probably doing plenty of fretting. (It’s not news that pregnancy gets tougher with age!) “And if they’re not worried, it’s not your job to scare them,” says Dr. Hill. When an older friend announces her pregnancy, just offer her the same sincere congratulations you’d give a younger one.