Some things never change. The sun rises in the east. Forks are set on the left. And if there is a pregnant woman in a movie, she will go into labor at the worst possible moment.

We should really know better. But this cliché is somehow still being rolled out in even the most acclaimed scripts. The latest offender is Alfonso Cuarón's Roma. But the inconvenient onset of labor is also used as the climax in A Quiet Place and a 2018 episode of The Handmaid's Tale.

Hollywood has long struggled to get pregnancy right, from amniotic sac geysers to hilariously bad labor scenes to disturbingly unrealistic newborns. To be fair, realistic pregnancy and labor aren't always what you're in the mood for; one might forgive a little glossing here and there. More at issue, though, is when a script hangs its narrative on a woman going into labor at the exact worst moment — say, when she's stuck at the bottom of a cave that is rapidly filling with water.

It probably goes without saying — but this is not how it typically works in real life. Your water breaks while you're sleeping or peeing or walking or doing any number of other totally mundane things. "Except in rare circumstances," said Mary P. Abernathy, a doctor of maternal-fetal medicine at the Indiana University School of Medicine, these movie "scenes have no bearing on how these mechanics work in real life. it is pure Hollywood magic." A woman's water breaking "is not caused by stress or fear. Otherwise women wanting to go into labor could just watch horror movies!"

But let's set aside questions of realism. There's a bigger problem here: Using a woman's pregnancy as the narrative climax of a film is old, it's tired, and it wobbles on the border of being sexist.

Women in literature have been inconveniently going into labor since Biblical times, when the unnamed wife of Phinehas gave birth abruptly after hearing that her husband and father-in-law were dead. More recently, the cliché has become a staple of romantic comedies, when a woman's water breaking is played for laughs. In the fourth season of Sex and the City, for example, Miranda just has to go into labor on Carrie's last night with Mr. Big. And in The Mindy Project, Mindy's water breaks on a stalled 2 train (okay, this one could probably happen). The cliché is so common that TV Tropes has an entire page calling it out.

But why do dramatic features, which don't have the excuse of passing their coincidental timing off as comedy, fall prey to this? In Roma, Cleo's water breaks when her baby's father just happens to storm into the exact department store (and floor!) where she is shopping for a crib. A Quiet Place builds an entire narrative around Evelyn's impending labor, so naturally her water breaks when her family is away on a fishing trip (typical!). Even in The Handmaid's Tale, when Jane is attempting escape while nine months pregnant, she only goes into labor as she is being stared down by, of all things, a wolf.

While this trope isn't exactly exploitative — these are fictional characters — there is something obnoxiously convenient about the way narrative plots hinge on a woman going into labor right at the most dramatic time. Women, made up or not, aren't tea kettles to whistle at the tensest moment in the movie. But going into ill-timed labor reduces a woman's body to a schlocky narrative device, one that creates anxiety by virtue of tugging on the strings of regressive, traditionalist themes: the mythical status of the mother; the innocence of the unborn child whose life is (probably) at risk. We should be better than this.

Biology doesn't adhere to a convenient schedule, in fiction or in life. There is no great time to go into labor, especially if you happen to live in a dystopia. But while births can certainly be dangerous in stories — Cuarón's earlier film, Children of Men, has Kee terrifyingly go into labor at a checkpoint — the issue is when they are used as the climax of the film, the lynch-pin in a project. Resist the deus ex utero, screenwriters: There are so many other ways to make a scene exciting and worthwhile than relying on silly coincidence and lazy tropes.

Many other clichés have rightly earned their place in the trash: the manic pixie dream girl, the weight-loss revenge plot. It's about time "labor as narrative climax" got thrown out, too.