On its release, 25 years ago next month, the Coen brothers’ blackly comic Minnesota-set crime movie Fargo made an immediate impression for several reasons. The inventive use of a wood chipper was one. Another was the “Minnesota-nice” demeanour — the chintzy perkiness of the characters’ conversational tics brought a layer of absurdity when juxtaposed with the film’s exuberant violence. But what really set the film apart was its depiction of pregnancy.

Marge Gunderson, Chief of Police in the snowbound small town of Brainerd, is seven months pregnant. Played by Frances McDormand, who won the Best Actress Oscar for the performance, Marge is bulky. She waddles slightly. McDormand described her at the time as “this large, solid piece of brown in amongst the white landscape”. But her pregnancy is incidental, it is rarely alluded to, and, barring a brief bout of crime-scene nausea, it has no bearing on her ability to do her job.

There is nothing daffy or distracted about Marge. She’s sharp, focused and, as her first scene in the film demonstrates, she’s a first-rate police detective. To quote McDormand again: “What’s really great about [Marge] is that she is so competent at her job. And the minute she gets to the crime scene, it becomes evident that she is not everything she appears to be. She is more.”

At the time, there was speculation that Fargo would set the tone for future depictions of pregnancy, that mothers-to-be would be allowed to be fully realised characters rather than bumps on legs. But, in fact, there have probably been more films featuring wood chipper body disposals in the past 25 years than there have been ones featuring characters who just happen to be pregnant. Television has acquitted itself slightly better, with Olivia Colman's pregnant detective in BBC spy series The Night Manager owing a clear debt to Fargo. But the character would not have been written as pregnant had not Colman discovered that she was expecting her second child during the casting process.

In the same way that showing somebody puffing on an inhaler pretty much guarantees they will have an asthma attack before the end of the film, revealing that a character is pregnant positions them a certain way within the story. Coming, as it does, with its own inbuilt three-act structure, perhaps it’s not surprising that pregnancy also brings with it a set of clichéd devices (waters breaking at moments of stress, nausea, getting wedged in small places).

Given that there are 211m pregnancies a year, according to WHO estimates, it is disappointing that the film industry still hasn’t worked out how to deal with them. But cinema’s problem with pregnancy dates right back to the early days of the medium. In Hollywood, the Production Code, which dictated what filmmakers between 1934 and 1968 could and couldn’t show, forbade depictions of actual childbirth. And while showing or discussing pregnancy was not expressly banned, the movie industry tied itself up in knots to avoid doing so.

Preston Sturges’s 1943 comedy The Miracle of Morgan’s Creek, for example, was quite racy for its time, featuring a central female character who attends a party for the troops and wakes up married, but unable to remember to whom. She is also, it turns out later, pregnant — with six babies. By rights, she should be the size of East Anglia. The real “miracle” is that there are no visible signs of pregnancy (she is coyly shot from behind or from the shoulders up, presumably to avoid traumatising the audience).

The Code’s attitude to pregnancy — and more broadly to female sexuality — was symptomatic of a broader malaise. And the conservative, Catholic, very male architects of the Code birthed a whole section of US society that is, even now, squeamish about female fertility and reproductive rights. This indirectly led to a sub-genre of pregnancy cinema: the abortion drama. A powerful recent example is Eliza Hittman’s Never Rarely Sometimes Always, which follows a teenager's journey from her home state to more liberal New York in order to secure a termination.

But it’s a story that is by no means limited to America. In 2007, the Cannes Palme d’Or-winning Romanian drama 4 Months, 3 Weeks and 2 Days brought a thriller-like intensity to a strikingly similar narrative. A handful of bold filmmakers — Alexander Payne with Citizen Ruth (1996), starring a glue-sniffing Laura Dern; Alex Thompson’s Saint Frances (2019) — have taken the transgressive step of adopting a comedic approach to the subject of abortion. But the vast majority of films that mine pregnancy for laughs take a more conventional trajectory.

More often than not, it starts with an unplanned pregnancy. Movies such as Juno, Knocked Up (both 2007) and the recent Baby Done from New Zealand explore the messy life-disrupting impact of an accidental pregnancy. But the fact that films such as these, plus the diabolical What to Expect When You’re Expecting (2012), place considerable emphasis on bump-based physical comedy tells us something about a certain type of male gaze prevalent in the film industry, which has fixed ideas about what kind of female body should claim screen time. The pregnant form, with its lumps and leaks and mysteries, is a cause for nervous laughter or outright alarm.

From here, it’s a short hop to horror, a genre that mines both the unnerving weirdness of having something growing within your body, and the additional vulnerability that pregnancy brings to a female character. Body horror supremo David Cronenberg regularly tapped into the ickiness and uncertainty of pregnancy with the notorious maggot birth nightmare sequence in The Fly (1986), and with The Brood (1979), into which he allegedly channelled the acrimony of his recent divorce.

The idea of the malevolent or parasitic foetus is a popular one, with Alice Lowe using her actual pregnancy as a prop in the killing-spree horror comedy Prevenge (2016). Most notable, though, is Roman Polanski’s Rosemary’s Baby (1968), which brings a feminist angle to the idea of demonic impregnation: Mia Farrow’s Rosemary finds that her pregnancy becomes public property, claimed by a coterie of creepy neighbours — an identifiable experience for many women.

But while the symbolic elements of pregnancy are particularly lurid in horror movies, even a film such as Fargo, with a character who just “happens” to be pregnant, comes with significant subliminal layers that add texture to the story. The screenwriter William Goldman, recalling Marge’s murder investigation scene, wrote the following: “After that scene I felt a sense of peace. I have seen everything the Coens have done, and I know they are perverse. But I could not conceive that even the Coens could kill Marge. Which meant I have faith I can give her my heart.”

McDormand observed that for the Coens, Marge’s pregnancy came with a dramaturgical element. “There was this idea that there was the ‘pregnancy of the future’ in Marge and Norm’s life. That they were the caretakers of the future, in amongst the craziness and the tragedy and the bizarre aspects of the movie.” But perhaps the genius of the decision to make Marge pregnant — and the reason that the film is rightly regarded as a masterpiece — is the way that it plays into what turns out to be one of the film’s central themes: that our assumptions and first impressions often reveal more about us than they do about the person we are looking at.

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