Like many expectant mothers these days, Autumn Yates posted updates about her pregnancy on Facebook.

“It’s nice for my extended family to see pictures from time to time of me getting bigger and little comments like, ‘34-week check-up went well!’ ” said Yates, 29, a Spanish teacher from Oakton. “I don’t see anything wrong with that. I think there is kind of a line sometimes, though.”

For Yates, that line is somewhere around “creepy” 4-D ultrasound photos and cringe-inducing comments such as, “My cervix is now dilated [fill in the blank] inches!”

In a world where it hasn’t happened unless it has been shared, parents and parents-to-be are increasingly posting photos of pregnancy tests, bulging bellies and swollen feet, and “Baby’s kicking!” status updates. More than 30 percent of American mothers have posted their sonograms online, according to a 2010 study by global security software maker AVG. By the time they are age 2, 92 percent of American babies will have an online presence.

“I think we’re definitely becoming more and more comfortable with just sharing our lives so publicly,” said Yates, who gave birth to a girl in May. “I think where I am is kind of right on the cusp: The following generation is even more open; people my age tend to be a little less forthcoming when using social media.”

Baby-bump posts aren’t restricted to Facebook and Twitter pics. Searching “Pregnancy ultrasound” on turns up 5,230 results. There are weekly “pregnancy diaries” full of ultrasounds, sonograms, photos and moms-to-be chattering for 3, 5, 10 minutes at a time about doctor appointments, the nursery, what to wear and what to pack in the hospital bag.

And the self-coverage doesn’t stop at the 40-week mark. Nancy Gaba, an associate professor of obstetrics and gynecology and vice chair of the OB-GYN department at George Washington University’s School of Medicine, has seen family members photographing and videotaping in the delivery room, as well as talking about uploading items to the Web.

“I have some people, like a patient’s mother, say to me, as I’m delivering a baby, ‘Could you move out of the way? I’m not getting a good enough shot,’ ” Gaba said. “I appreciate that they’re trying to memorialize their special moment, but there are certain times when we have to say ‘Okay, you photographers all need to step aside so we can do what we need to do.’ ”

“Sometimes I ask people, ‘Who are you actually going to share that picture with?’ ” she said with a laugh. “It’s one thing to have a picture of mom holding the new baby. It’s quite a different thing to have a picture of the baby during the actual delivery.”

The deluge of pregnancy reports in social media can be so overwhelming at times that, for offbeat site Newslite’s April Fool’s Day coverage, Simon Crisp wrote a joke story about a Facebook application for users to block friends’ baby- and marriage-related posts.

“If the option was real I would have it activated in an instant,” Crisp said in an e-mail.

But Mary Madden, a senior research specialist with the Pew Internet and American Life Project, said that a memoir about pregnancy would offer personal details much like the ones shared online. Social media “collapse all of our personal networks in one space,” she said, allowing the user to reach all connections at once: updates to Mom, a middle-school classmate and a pregnant friend.

“Pregnancy is a point of entry into this community” of moms and moms-to-be, Madden said. “And the sense of oversharing, while it may seem like oversharing to someone outside that community, is actually a gift to someone in the community looking for comfort.”

For 31-year-old Laura Steichen of Cleveland Park, Facebook allowed many of her peripheral friends, as well as cousins and co-workers, to keep close tabs on Baby Steichen. “They know more than my mom does about my pregnancy,” said Steichen, whose mother doesn’t have Facebook.

Kate Myers was negotiating a job in social media at NPR when she found out she was pregnant. She and her husband told a few people, but no one at work. Those they did tell were warned by Myers to observe a “complete social media blackout” so she could keep control of the news.

“Social media for me was the easiest way for something to spread out of control,” said Myers, 29, of Silver Spring. “I wanted to make sure my pregnancy wasn’t a positive or a negative reason to hire me.”

When Myers was negotiating specifics on her new job — and her belly was becoming a bit harder to hide at 22 weeks — she decided it was okay to post a photo of her pregnant self.

Although the social media blackout was never officially lifted, Myers occasionally posted baby-related updates after Isaac was born: “Just got jury summons for April 11, 2011. Had to defer by repeating 5 times for the old man that I was due to give birth the day before.”

But never, ever, belly-baring photos.

Anderson is a freelance writer.