Mercedes Forrest first heard about postnatal retreats when one of her favorite Peloton instructors, Becs Gentry, posted on Instagram about her stay at Boram Postnatal Retreat, the first such center in the U.S. Forrest watched Gentry and her husband celebrate their newborn by checking into a luxury hotel, sipping champagne, and munching on protein-rich meals of salmon and seasonal salads.