Technology is changing how we make babies, and it’s come a long, long way since the first “test tube baby” in 1978. This week, we’re diving into the cutting edge of IVF - think AI, robots, and potentially gene-edited embryos - but first, a look back at how we got here, because nothing says progress like moving from “hope for the best” to “let’s run some genetic tests first.”
In the early 1990s, Alan Penzias, a reproductive endocrinologist at Boston IVF, worked at Yale culturing embryos for a mere two days until they had two to four cells. They couldn’t survive longer outside a body, so all of them - say, five embryos - were transferred to the uterus. Healthy patients could expect a live birth rate of 12% to 15%, which is to say, it was a bit of a crapshoot. When Penzias heard other teams were culturing embryos for three days, he recalls thinking, “No, that’s not possible.” But they’d tinkered with the culture medium, and those three-day embryos (six to 10 cells) boosted success rates to 25%. Penzias says, “We thought they were making it up.” Ah, the good old days of disbelief.
Since then, improvements to culture medium have allowed embryos to be grown for five or six days, reaching 80 to 100 cells. The process acts like a stress test: embryos that survive that long are more likely to become healthy babies. Over the same period, freezing techniques evolved. A little over a decade ago, clinics adopted “vitrification,” rapidly cooling embryos to a glassy state, making them more likely to survive thawing. This meant doctors no longer needed to transfer multiple embryos at once, reducing risky twin or triplet pregnancies. Vitrification also gave patients a breather between hormonal treatments, lowering the risk of ovarian hyperstimulation syndrome (OHSS), a condition that can be life-threatening in rare cases.
Now that clinics can culture embryos for up to a week, they can snip a few cells for genetic testing before freezing. People undergoing IVF get genetic readouts of all their embryos before deciding which to implant (though the tests aren’t perfect). “Those are really radical changes, and we take them for granted,” says Penzias. Indeed, IVF has shifted from a treatment for infertility to a tool for fertility preservation. People can freeze eggs or embryos to delay parenthood, or store reproductive material before cancer treatments. Scientists have even preserved ovarian and testicular tissue and reimplanted it later, enabling healthy babies.
Today, more people than ever have access to safe IVF options, and those options look set to expand. Want to know about AI and IVF robots? You’ll have to read this week’s story. But for now, raise a glass (or a petri dish) to half a century of progress - from 12% success rates to gene-edited possibilities.