The placenta is incredible: it’s an entire organ that’s created at the beginning of pregnancy and is then delivered after the baby is born, as it’s no longer needed. But several of the issues that arise during pregnancy can be traced back, at least in part, to issues with the placenta. Over the last few years, a team of scientists led by Jo James and Alys Clark, both researchers at the University of Auckland in New Zealand, has developed computer programs that integrate data from the lab and the clinic about healthy pregnancies and those in which issues arise to create a so-called virtual placenta. They use the virtual placenta to study the differences between healthy and unhealthy placentas, and it may eventually help care providers catch pregnancy complications.
In a series of studies in which they use the virtual placenta to learn more about different aspects of maternal and fetal interactions, James, Clark, and colleagues explain that in 10 percent of pregnancies, placentas do not behave how they should, leading to complications, the most severe of which is intrauterine or fetal growth restriction (IUGR). Because the placenta is responsible for getting baby all of the nutrients and oxygen it needs to grow in utero and there is a careful interface of mother and baby’s blood vessels, if something goes wrong with the placenta, it may mean that baby grows more slowly. IUGR can be most dangerous if baby stops growing all together and needs to be born sooner rather than later, perhaps via induction or cesarean section. If IUGR goes undetected, the risk of stillbirth is much higher.
The researchers developed their computer program to better understand the placenta because, while it’s known that some things—like smoking—can influence placenta health, other times things unexpectedly go wrong in pregnancies of people with no known issues and through no fault of the pregnant person. When you go in for prenatal visits, your care provider likely measures the height of the top of your uterus to estimate baby’s growth or you may have an ultrasound, which can also be used to estimate fetal growth, although ultrasound is notoriously inaccurate the further along a pregnancy is.
In 2015, Clark, James, and colleagues published a paper [1] in which they used computer programs to understand how the blood vessels in the placenta interact with those of the pregnant person to get the baby oxygen and nutrients. They used their virtual model of the way that the blood vessels interact to determine that an umbilical cord inserted nearer to the center of the placenta—as most are—would likely lead to more consistent blood flow between mother and fetus than a cord that was within an inch or so of the edge of the placenta. The research team also found that normal variations in placental shape (some placentas are slightly more oval than others, for instance) were unlikely to affect how efficiently the placenta gets nutrients and oxygen to and removes waste products from baby.
In another study published in 2018 [2], Clark, James, and coauthors used an updated computer program that included even more information about how the blood vessels in the uterus and placenta interact. They showed that differences in how the vessels in the placenta form can make the flow of blood through the uterus sound different as heard on a Doppler (the machine that picks up on baby’s heartbeat but can also detect the soundwaves of the pregnant person’s blood whooshing). The flow of blood through the uterus as detected by Doppler can be an indicator of preeclampsia, so understanding better how the shape and interaction of the blood vessels in the placenta and the uterus using a virtual placenta model may help researchers and physicians better understand this challenging and hard-to-predict condition. In this way, a computer version of an organ could lead to better medical care for pregnant people.
- Clark A. R., Lin M., Tawhai M., Saghian R. and James J. L. Multiscale modelling of the feto–placental vasculature. Interface Focus. 2015.
- Clark A. R., James J. L. et al. Understanding abnormal uterine artery Doppler waveforms: A novel computational model to explore potential causes within the utero-placental vasculature. 2018.
