In the 1950s, photojournalist Lennart Nilsson set out to capture the earliest stages of existence. His foetus images seized the public imagination – and sparked a controversy that has raged ever since

In April 1965, Life magazine put a photograph called Foetus 18 Weeks on its cover and caused a sensation. The issue was a spectacular success, the fastest-selling copy in Life’s entire history. In full colour and crystal clear detail, the picture showed a foetus in its amniotic sac, with its umbilical cord winding off to the placenta. The unborn child, floating in a seemingly cosmic backdrop, appears vulnerable yet serene. Its eyes are closed and its tiny, perfectly formed fists are clutched to its chest.

Capturing that most universal of subjects, our own creation, Foetus 18 Weeks was one of the 20th century’s great photographs, as emotive as it was technically impressive, even by today’s standards. And its impact was enormous, growing into something its creator struggled to control, as the image was hijacked by the fledgling anti-abortion movement.

Foetus 18 Weeks was taken by Lennart Nilsson, part of an astonishing series of prenatal pictures by this visionary Swedish photojournalist. His groundbreaking pictures have now reached a whole new generation, having just been shown at the Paris Photo art fair, the first time they have ever been exhibited outside Sweden. There is talk of a further appearance in Vienna.

Facebook Twitter Pinterest Womb timeline … Foetus 20 Weeks. Photograph: ©Lennart Nilsson Photography

Nilsson told the editors of Life his plans to capture the beginnings of human existence while visiting New York in 1954. “It was impossible for us not to express a degree of scepticism about his chances of success,” one later recalled, “but this was lost on Nilsson.” A decade later, he returned with the first photographs, shot in both colour and black and white – an unprecedented feat that fused photography and biological study. They were published in Life as an iconic photo essay, entitled Drama of Life Before Birth.

Ultrasound technology was first introduced for clinical purposes in Glasgow in 1956. But charting an unborn child’s development through such images was not common in hospitals until the 1970s, and even today the quality is poor. So instead, Nilsson enlisted the help of two endoscope experts, the German company Karl Storz, and the Swedish Jungners Optiska, who created optical tubes with macro lenses and wide-angled optics that could be inserted into a woman’s body.

Nilsson was only able to photograph one living foetus, though, using an endoscopic camera that travelled into a womb. This picture was included in Life and is distinct from the others – being taken inside the uterus means it can’t capture the foetus in its entirety. All the other images were either miscarried or terminated pregnancies.

The photographer worked closely with Professor Axel Ingelman-Sundberg, then head of the women’s clinic at the Sabbatsberg hospital in Stockholm, taking hundreds of shots with his Hasselblad camera from 1958 to 1965. Whenever the hospital had access to a foetus (or embryo) Nilsson could photograph, they would call him immediately – it was essential to photograph them within a few hours.

Facebook Twitter Pinterest Nilsson in surgical scrubs with his endoscopic camera equipment. Photograph: Life Magazine/The LIFE Images Collection via Getty Images

Nilsson had set up a studio at the hospital where his subjects would be placed in an aquarium-like environment, which is why they appear to float in space. Together, his shots create a spellbinding timeline, from an egg fertilised with sperm to foetuses at various stages up to six months.

Nilsson also published the pictures in A Child Is Born, intended as a guide for mothers to be. It is one of the top-selling illustrated books of all time, having been translated into 20 languages. His interest in looking inside bodies to understand the unseen would continue after his foetus series: Nilsson is credited with taking the first photographs of the SARS and HIV viruses. After the rise of television, he turned to moving pictures, making such documentaries as the 1982 Emmy-award winning film The Saga of Life.

Following the huge success of both the Life cover and A Child is Born, Nilsson became world famous. Anne Fjellström, his stepdaughter, worked as an assistant on a 1990 edition of A Child is Born and became enthralled by his work. “I’ve spent the last 20 years trying to understand it,” says Fjellström, who is now in charge of his estate.

As the women’s liberation movement grew, and debate over reproductive rights raged, Nilsson’s pictures became intensely politicised, especially in the US in the 1970s. But Nilsson was working in Sweden and wasn’t aware of the strong reactions his images were causing abroad. It was only on a trip to London in the 1980s, when Nilsson saw his plagiarised pictures printed on posters at an anti-abortion protest, that he became aware of how they were being used. He was, Fjellström recalls, deeply shocked.

Facebook Twitter Pinterest The Life cover from the 30 April issue. Photograph: Photo 12/Universal Images Group via Getty Images

After seeing this, Nilsson refused to allow the photographs to be published again. “Lennart wasn’t a political person,” says Fjellström, though this hasn’t stopped the images being appropriated by anti-abortion campaigners, most recently in Ireland and the US, and the requests keep coming. “I get emails every week,” she says. “But we remain neutral. The material was not made for that purpose and that must be respected.”

However, Nilsson returned to the images shortly before his death in 2017, at the age of 94. He arranged them into a definitive black and white series, so that museums and public collections might be able to access and display them after his death. They were intended to be his legacy. The selection for Paris Photo, which gave the shots an international stage, was put together by Fjellström and Jan Stene, director of Stene Projects, a gallery in Stockholm.

The images caused a stir in Paris and it’s easy to see why: their quiet beauty has a powerful emotional pull. “Nilsson,” says Stene, “wanted to make the invisible visible – and show us the astonishing journey we all make, one that unites all humans. He wanted to give us an opportunity to look inside ourselves, to discover pictures that define us as humankind.”

Nilsson, says Fjellström, was “a very private person” who usually worked alone. How capturing these images might have affected him psychologically remains unclear. “I think he understood that the issue was complicated,” she says. “But like most journalists, he was focused on what he wanted. I know he was amazed by what he saw and wanted to reveal how amazing our common journey is.”

Facebook Twitter Pinterest ‘He was amazed by what he saw’ … Foetus 13 weeks (Spaceman) . Photograph: Lennart Nilsson Photography

Stene accepts that the images have divided opinion over the polemical question of when life begins, but says: “Everyone interprets images differently, depending on their social, cultural and religious background. In the digital era, I believe it is more important than ever to go back and take a look inside ourselves. What better way of doing that than with these photos?”

Last year, Stene points out, the first ever photograph of a black hole was published. “For me,” he says, “looking at that picture and looking at one of the foetus photos are the same thing. After all, what do we really know about the origin of mankind and the universe?”

• This article was amended on 20 November 2019 because an earlier version said that both of the endoscope expert companies enlisted by Lennart Nilsson, Karl Storz and Jungners Optiska, were German. This has been corrected to refer to the latter as Swedish.