Doulas provide physical and emotional support before, during and after birth. Such care used to be seen as a luxury and was available only to those who could afford it. But now, doulas are becoming mainstream. Insurance coverage is growing fast, making their services more available to parents from across the economic spectrum. More than 30 states reimburse doulas through Medicaid or are in the process of implementing such coverage. And private insurers are starting to do the same. Without insurance, costs vary widely but can exceed $2,000. One big reason for the change is that mounting research shows doulas improve health outcomes for moms and babies, including the most vulnerable ones.

Every year, math nerds and dessert enthusiasts unite to celebrate Pi Day on March 14, a date whose digits represent the first three digits of the mathematical constant pi. The holiday was created in 1988 by Larry Shaw, a physicist at the Exploratorium science museum in San Francisco. In school, you might have used it to calculate the area of a circle or the volume of a cylinder, but the applications of pi are endless and part of every corner of our world. Pi is involved in every step of aerospace engineering and is also on the cutting edge of medical research.