Miscarriages may be more likely to occur with slowly developing embryos

Embryos may develop more slowly in some pregnancies that end in miscarriage, according to a study that uses virtual reality to visualize them using vaginal ultrasounds.

The discovery could be a step towards early prediction of a pregnancy if it is likely to lead to miscarriagealthough the technique is not yet ready for clinical use, says Melek Roussian at the Erasmus University Medical Center in Rotterdam, the Netherlands.

More than half of all pregnancies end in miscarriage, although in many cases it happens so early that people don’t even realize they were pregnant. Some people have multiple miscarriages without knowing why, which means their pregnancy can be a big time. anxiety.

To learn more about the causes of miscarriages, Rousian’s team developed a way to use vaginal ultrasounds to create a highly detailed 3D image of a embryo. The image is zoomed in until it is roughly the size of an adult, then visually inspected by researchers while wearing virtual reality headsets.

The team created these images for 644 pregnant women, 33 of whom had miscarriages. Transgender people were not included in the study.

By examining the 3D images, produced about eight weeks after conception, the researchers found that, on average, embryos that eventually miscarried developed more slowly than pregnancies that continued to term.

Embryonic maturity was assessed through the so-called Carnegie staging system, which indicates what physical characteristics have developed, such as limb buds and early facial features, according to a 23-step scale.

The team found that a woman’s risk of miscarriage increased by 1.5% per delayed Carnegie stage.

At eight weeks post-conception, that equates to a developmental delay of around four days for embryos that miscarried, the researchers said. “Four days is a pretty big gap in a very important period of life where all the organs are developing, all the limbs are developing,” says one team member Carsten Pieterma.

If the results are confirmed in larger studies, it could allow doctors to tell people whether or not their embryo is developing normally, Rousian says.

It is unclear why embryos that develop more slowly may be more susceptible to miscarriage. Other work has shown that embryos or fetuses that miscarry often have alterations or different numbers of chromosomesthe parcels of DNA contained in almost all our cells.

Ruth Bender Atik At Miscarriage Associationa UK supporting charity, says that while 3D embryo imaging may reassure some people, it can also cause uncertainty and anxiety.

Some people who have already had a miscarriage may not want the vaginal ultrasound, while others may be desperate to check on their pregnancy progress, she says.