In December, Kayla Itsines, personal trainer and founder of the fitness system Bikini Body Guide, posted a glowing photo of herself with a tiny “baby bump” at 20 weeks’ gestation. It’s the latest in a recent explosion of pictures of extremely fit pregnant and recently postpartum women, brought to you mostly by Instagram. The recurrent presence of these small-bump images in my life is a testimony to the internet’s power to aggregate and replicate—one that I could very much do without.

We can’t totally blame social media for this emerging 21st-century belief that a pregnant woman should—somehow!—be thin. Back in 2004, Laurie Abraham wrote a feature for New York magazine about Manhattan women who were trying to get through pregnancy with the least possible weight gain. The article was a terrifying harbinger of the Instagram pregnancy apocalypse to come. Rumors of cesarean sections scheduled at eight months, to avoid gaining “the last little dollop of fat”! Size-27 jeans, worn at five months’ gestation! One woman who wouldn’t tell her husband how much she weighed, only relenting when the anesthesiologist in the birthing room needed the number to give her the right amount of medicine in her epidural! It was all very New York then—but now, it seems, we’re all New Yorkers.

When, near the end of her feature, Abraham cuts to “the elephant in the room,” she’s talking about the matter of the health of the infant. (Yes, the baby of a very fit pregnant woman will probably be OK, except in extreme circumstances of famine.) But the real “elephants” here are patriarchy and misogyny. Why do we now fret and strain and punish ourselves to make sure pregnancy takes as small a toll on our bodies as possible? It’s because we live in a culture where women are never allowed to “give up”—to let their bodies get older, softer, and larger, to be changed by circumstances and the passage of time. A tiny “baby bump” on an otherwise perfect body tells the world: You’ll be a mom, but you won’t be one of “those moms,” the ones who remind everyone they’re mortal.

We live in a culture where women are never allowed to “give up.”

I first saw photos of fit-pregnant Instagrammers before I got pregnant, and they were simply a compelling bio-cultural artifact—something, I thought, that might end up in the Mütter Museum in 50 years. When I became pregnant, I understood how unrepresentative these images were of my experience. I was nauseated for 21 weeks; when I stopped being so sick that I needed to lie down whenever I could, I was hot all the time, and so hungry that I kept a bag of roasted chickpeas under my pillow so I could eat them and get back to sleep after my hunger woke me up at night. I was (am again, now) an exerciser and thought before pregnancy that I’d keep on with my routines, but it felt like my baby wasn’t simply located in my midsection; she spread all through my cells, transforming me into a different kind of animal. These anodyne fit-pregnancy prescriptions—“Go to the gym as normal, unless you have discomfort!” and “Just eat healthy!”—meant nothing to the creaky, overheated beast that I’d become. And after the baby arrived, and my entire life needed to be reorganized on little sleep, the idea of flagellating my body back into “shape” was even less appealing.

Every critique of pregnant weight gain, and postpartum weight retention, contains a keyword: excuse. That’s what I just made, in the paragraph above. A pregnant or postpartum woman who gains “too much” weight, or fails to lose it quickly enough, has committed the sin of “making excuses.” Because misogyny turns women against one another, you hear it very often from women. An avid runner interviewed in the New York magazine article, who reported that exercise just felt “natural” to her during pregnancy (bully for you!), added to writer Abraham, “I’m the first to admit that I didn’t see pregnancy as an excuse to sit on my ass and let the pounds come.” Maria Kang, who calls herself “the fit mom,” made “What’s your excuse?” her catchphrase. There’s even a hashtag on Instagram: #noexcusesmom.

The presumption of the “No excuses” trope is that mothers are leaning on motherhood to indulge their natural tendency to be lazy and gluttonous. This idea is misogynistic. If you need this thought confirmed, look at the way misogynists talk about pregnancy and weight. “Pregnancy is no excuse to be fat and gross,” RedPiller1985 blogged on the now-dormant “neomasculinist” pickup-artist site Return of Kings. “There’s an epidemic of land whales in first world countries bitching about post pregnancy bellies, blaming even their own children for being fat.” Mr. RedPiller allowed that it might take a year to get back to a pre-pregnancy body but thought that “big” women who had given birth a year before or more should be called out with “subtle remarks,” recommending that readers “ask the fat mother her due date … we have an obligation as a society to help fat mothers be more aesthetically pleasing.”

The men who say terrible things about women on the internet are sure that women only stay thin before they have children because they want to “catch” a man. The advent of children in a marriage is a sign for women to “let themselves go.” (“The language of ‘letting yourself go’ is not benign,” Elissa Strauss wrote in Slate in 2016. “Where exactly have these women’s selves gone?”) A now-banned commenter on the Bodybuilding.com forums started a thread in 2011: “I hate pregnant women who use it as an excuse to get fat and stay fat afterwards.” Women, this person thought, were “all fat liars who use being pregnant as an excuse to finally give in to their inner pig.” Another person added, “Women are just lazy and like to make excuses for themselves. Plus once you have a baby with a chick you’re stuck anyway.”

For this kind of person, the “fit pregnancy” photos that fly around the web are proof that pregnancy doesn’t have to “wreck” a woman’s body, if the woman cares enough to work for it. Commenters on the Return of Kings post referred to this picture of Caroline Berg Eriksen, the wife of a Norwegian soccer player, with washboard abs in lingerie, which she posted on Instagram four days after giving birth. “This is the only selfie I wholeheartedly approve of,” one wrote. “Moms who look like that after having kids should show themselves off.”

The issue isn’t just the fat of motherhood. It’s what that fat symbolizes: a failure to weather pregnancy without bothering anyone. In a head-exploding piece about dating while thin in the New Inquiry, Alana Massey perceptively noted that men have evolved a series of euphemisms to describe the kinds of women they liked to date: active, full of energy, a woman who takes care of herself. These, Massey wrote, are all code words for thinness: “He isn’t asking that her household finances be in order and that she be self-actualized. He is asking her to be thin.” The most “troubling” kind of such a man, Massey argued, wanted a woman who was thin without being “obsessed” or “overly concerned.” “For a thin woman to betray the reality of her diet and regimen for staying that way would spoil the fantasy of a woman who is preternaturally inclined to her size rather than personally preoccupied by it.”

This is why every Instagram fit-pregnant person swears that it’s not hard to do. And this is why some of them report that they also get criticized—for spending “too much time” on themselves and “not enough” with their kids. The perfect fit pregnancy, and fit recovery, must project the ultimate illusion of womanly effortlessness. The fit-pregnant person gives her body to her child, as its home; meanwhile, she keeps her body “right” for her presumably appreciative husband. The ideal mother carries a baby in her body, breastfeeds, pumps breast milk, goes back to work or doesn’t, all without imposing on anyone else with her troubles. Somehow, she does everything, while barely existing at all.