RESUMEN
BACKGROUND: Labor pain is difficult to measure. The aim of this proof-of-concept study is to implement and test a questionnaire assessing pain sensation during and after vaginal deliveries. Its key aspect is a highly standardized survey of patient-reported outcome (PRO) by staff not involved in routine care. METHODS: Between January and November 2015 339 women were assessed 24-48 h after spontaneous or operative-vaginal delivery of a singleton. German language skills were a prerequisite to participate. The test-retest reliability was calculated in 38 women 24-36 and 48-72 h postpartum between July and October 2017. Primiparae after spontaneous delivery and multiparae with no history of operative deliveries were compared in a subgroup analysis. RESULTS: Maximum labor pain and post-partum pain were reported a median of 9 [8-10] and 4 [3-6]. Higher ratings were associated with younger age, higher gestational ages, infant's biometrics, and the duration of laboring. Only regional analgesia tended to reduce pain perception (NRS 8 vs. 9). Higher-degree injuries were associated with less pain postpartum. The questionnaire proved to be reliable in most aspects (Cronbach's α > 0.6 for 19/21 questions) and showed an acceptable content and criterion validity (Cohen correlation > ± 0.3, interrelation between items). CONCLUSION: Labor is a very painful experience, irrespective of previous obstetric history. Ratings indicate inadequateness of treatment except for patients receiving preventive postoperative pain management. Systematic postpartum pain assessment, hence, is still a pending issue. Adjustments will be made concerning language skills and specific questions on effectiveness of analgesia otherwise good reliability and validity of the questionnaire were proven.