mothers in New Zealand over a five-day inpatient treatment in a sleep lab.15 The goal of the stay in the lab was to sleep train the infants. Nurses in the study collected data on the stress hormone cortisol in both the babies and their mothers, and were also responsible for putting the infants to sleep, and monitoring the sleep training. Before the sleep training each day, the babies’ and moms’ cortisol levels were tested and recorded.
