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Researchers have engineered a replica of the human womb lining in a laboratory dish, a development that could help scientists unravel the earliest and least understood stages of pregnancy and the biological faults that can contribute to miscarriage and other medical complications.
In experiments, early-stage human embryos donated by couples following IVF treatment were able to attach to and embed within the engineered tissue. After implantation, the embryos began producing key compounds associated with early pregnancy, including the hormone linked to the “blue line” on positive pregnancy tests.
A window into the embryo–uterus “chemical chatter”
The research team used the system to monitor the molecular back-and-forth between a developing embryo and the womb lining as implantation occurs and nourishment begins in the first weeks of gestation. This chemical signalling is considered essential for a pregnancy to become established and remain healthy.
“It’s incredible to see it,” said Dr Peter Rugg-Gunn, a senior author on the study and group leader at the Babraham Institute in Cambridge. He said that, until now, scientists largely relied on limited “snapshots” of this pivotal stage. “Previously we’ve only had snapshots of this critical stage of pregnancy. This opens up a lot of new directions for us,” he added.
Implantation typically happens around a week after fertilisation, when the embryo attaches to the uterine wall and embeds into it. Despite its importance, the process has remained difficult to study directly. Much of the historical knowledge comes from hysterectomies carried out in early pregnancy more than half a century ago.
How the engineered womb lining was created
To construct the replica, Rugg-Gunn and colleagues obtained uterine tissue from healthy women who provided biopsy samples. The scientists separated two key cell types: stromal cells, which provide structural support within the womb lining, and epithelial cells, which form its surface.
The stromal cells were encapsulated in a biodegradable hydrogel, and epithelial cells were layered on top, creating a laboratory version of the uterine lining designed to support implantation.
Embryos implanted and produced hCG up to the 14-day legal limit
When tested with donated IVF embryos, the engineered lining supported attachment and implantation. Reporting in Cell, the researchers described how embryos embedded as intended and then increased secretion of human chorionic gonadotropin (hCG), the biochemical marker detected by pregnancy tests, alongside other pregnancy-related compounds.
The system allowed embryos to be observed for up to 14 days after fertilisation, the legal limit for embryo research. Over that period, the embryos developed specialised cells and other cell types associated with placental growth.
To probe implantation in more detail, the team focused on the sites where embryos had embedded and decoded molecular messages exchanged between the embryo and the engineered womb lining.
Testing what can go wrong—and potential paths to better IVF outcomes
Scientists plan to use the platform to study how pregnancies become established and why the process often fails. “We know that half of all embryos fail to implant and we have no idea why,” Rugg-Gunn said, adding that understanding these failures could ultimately help improve IVF success rates.
Further work will also examine events after implantation, when placental formation begins—a period linked to many serious pregnancy complications. In the reported study, the researchers used a chemical to block a specific signal between the embryo and the lining. This produced severe defects in the tissue that forms the placenta, highlighting how the model can be used to test the effects of disrupted signalling.
In a separate paper published in the same journal, Chinese researchers described their own replica womb lining and reported identifying drugs that could improve implantation in patients with recurrent implantation failure (RIF), a condition in which good-quality IVF embryos repeatedly fail to establish a pregnancy. That study is available here: https://www.cell.com/cell/fulltext/S0092-8674(25)01230-9.
John Aplin, a professor of reproductive medicine at the University of Manchester, said that implantation rates had remained persistently low over more than four decades of assisted reproduction. He explained that as implantation occurs, a biological programme starts that drives placental development, which will provide nutrients and oxygen to the foetus.
“The earliest stages are crucial to the progression of the pregnancy, are not well understood, and frequently fail,” Aplin said. “This work will allow treatments to be explored that seek to improve implantation efficiency.”
Related reading: Equivalent of one child in every British classroom now born via IVF, data shows.
