Acute Urinary Retention During Pregnancy -A Nationwide Population-Based Cohort Study in Taiwan Jeng-Sheng Chen1, Chin-Li Lu2, Hsin-Yi Yang2, Panchalli Wang3, Li-Chung Huang4, Solomon Chih-Cheng Chen2, Fu-Shun Liu5 1.Department of Urology, Sinying Hospital, Ministry of Health and Welfare, Sinying, Taiwan. 2.Department of Medical Research, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi, Taiwan. 3.Department of Gynecology, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi, Taiwan. 4.Department of Psychiatric, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi, Taiwan. 5.Department of Emergency, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chia-Yi, Taiwan. Introduction Acute urinary retention (AUR) is common in elderly men but unusual in women. Pregnant women are relatively young, and AUR during pregnancy is rare. Most of the reported AUR cases during pregnancy are self-limited, however, some may require more aggressive surgical interventions. This study aimed to investigate the epidemiology and potential risk factors of AUR during pregnancy using a nationwide population-based database. Materials and methods We included all cases of pregnancies with AUR reported in Taiwan’s Longitudinal Health Insurance Database from January 1, 1998, to December 31, 2011. We excluded cases of AUR onset one day before delivery. The Cochrane-Armitage trend test and logistic regression analysis to evaluate the age distribution and types of deliveries of pregnant women. Chi-squared tests and Fisher's exact test to examine the association among all covariates. The odds ratios (OR) and 95% confidence intervals (CI) were estimated. Results Table 1：Age and delivery distribution in pregnant women with and without AUR (n = 65,490) Table 2：Covariate comparisons between the AUR and non-AUR groups in women with a normal delivery Conclusion The risk of AUR during pregnancy is 0.47%. Women with advanced maternal age (> 35 years-old) and those who experience preterm delivery have an increased risk for AUR. The peak incidence of AUR onset in normal pregnancies occurred between the 9th and 16th gestational weeks. To minimize AUR-related complications and identify high-risk pregnancies, the early diagnosis, appropriate treatment, careful evaluation, and close follow-up of AUR during pregnancy are necessary. (The authors have no funding and conflicts of interest to disclose) Figure 1: Frequency of the first AUR event in normal pregnancies by eight-week gestational intervals. (n=191)   AUR+ (N = 308) AUR- (N = 65,182) Positive rate c (%) P value a Odd ratio P value b Maternal age <20 7 2753 0.25 <0.001 reference 20-24 57 13559 0.42 1.76 0.16 25-29 103 24631 1.69 0.18 30-34 94 18703 0.50 1.82 0.13 35+ 47 5536 0.84 2.62 0.02 Delivery Pre-term 100 4491 2.18 6.33 Normal delivery 191 56963 0.33 Reference Post-term 17 3728d 0.46 1.29 0.31 Covariates, n (%) AUR+ AUR- 　P value Diabetes mellitus 　0 27 (0.04) 1.000 Gestational diabetes mellitus 2 (0.65) 10 (0.02) 0.001 Urinary tract infection 11 (3.57) 4 (0.01) <0.001 Inflammatory pelvis 1 (0.32) 2 (0.00) 0.014 Inflammation of the cervix, vagina, and vulva 0.005 Genital herpes 0.003 Intervertebral disc disease 　 0 Leiomyoma 110 (0.17) 0.098 Previous delivery 53 (17.2) 19,023 (29.2) Previous abortion 14 (4.55) 716 (1.10) Abnormality of the pelvis 13 (4.22) 260 (0.40) Malposition / malpresentation 3 (0.97) 293 (0.45) 0.164 Disproportion 102 (0.16) Hydra- or oligo-hydramnios 1,497 (2.30) 0.128 Endometriosis 1,022 (1.57) Dysmenorrhea 　 0 16 (0.02) Ectopic pregnancy 1,665 (2.55) 0.272