Nitrous oxide labor analgesia and pain relief memory in breastfeeding women.

Objective: The use of labor pain relief medications is a controversial issue that has engendered heated discussions among health care professionals about safety, interference with birthing, and breastfeeding.

Methods: This is a case-control study with 62 puerperae treated with nitrous oxide and 124 control women (ratio 1:2), matched for age, gestational age, parity, delivery route, labor augmentation, and spinal regional analgesia. We tested anhedonia, anxiety, and depression symptoms at hospital discharge by The Edinburgh Postnatal Depression Scale (EPDS), and the intensity of nitrous oxide labor pain relief and satisfaction memory by a retrospective Visual Analog Scale (VAS, 0-10 Numeric Rating Scale) at a set cut off time of 3 months of a child's age.