Researchers found that every pregnancy rewires the brain in its own way, with a second pregnancy bringing a different pattern of changes than the first. The discoveries could lead to better ways to recognize and treat maternal mental health challenges, including peripartum depression.

Heavy marijuana smoking may raise the risk of lung cancer and several head and neck cancers, according to growing research, but many important questions remain unanswered. Scientists are still trying to determine how much marijuana use is enough to significantly increase cancer risk. Edibles have not been linked to lung cancer so far, while the long-term effects of vaping marijuana and secondhand marijuana smoke are still being investigated.

A new once-daily weight-loss pill called orforglipron delivered better weight loss and blood sugar improvements than the leading oral semaglutide in a major clinical trial. The tablet could offer a more convenient alternative to injectable drugs like Ozempic and Wegovy because it doesn't require refrigeration or special timing with meals. It's also cheaper to manufacture, which could expand access globally.

A large study found that pregnant women are exposed to dozens of common chemicals, many of which were associated with earlier births and lower birth weights. Researchers also discovered that some replacement chemicals may be just as concerning as the substances they were designed to replace.

Teens who use cannabis may face a substantially greater risk of developing serious mental health conditions, including psychotic and bipolar disorders, according to a study of more than 463,000 adolescents. Researchers found cannabis use often preceded these diagnoses by nearly two years, strengthening concerns about its long-term effects on developing brains.