Researchers at the National Institutes of Health have developed a prototype device that could potentially diagnose pregnancy complications by monitoring the oxygen level of the placenta. The device sends near-infrared light through the pregnant person’s abdomen to measure oxygen levels in the arterial and venous network in the placenta. The method was used to study anterior placenta, which is attached to the front wall of the uterus. The researchers described their results as promising but added that further study is needed before the device could be used routinely.