Three-Dimensional Anorectal Manometry Findings in Primigravida

Vaginal delivery is an identified risk factor for anal sphincter injury. Therefore, to identify postpartum injury, an antepartum value or a normal range is required. However, at present, the normal values of 3D manometry are not available for primigravida or pregnant mothers. Our study aims at describing normal values of 3D manometry in primigravida. We analyzed 3DARM data of 101 consecutive primigravid mothers in the third trimester. 3DARM was performed using the Given Imaging(A (R)) ManoScan system. The mean age was 24.7 (SD 5.1) years. All patients had a normal Cleveland Clinic Incontinence Score. The mean resting pressure (RP) was 87.02 (SD 18.43) mmHg and the maximum squeeze pressure (SP) was 179.21 (SD 52.96) mmHg. The mean length of the high-pressure zone (HPZ) was 3.67 (SD 0.52) cm. Mean volumes for initial rectal sensation, urge, and discomfort were 50.36 (+/- 25.57), 76.70 (+/- 35.17), and 143.40 (+/- 66.26) ml, respectively. The pressure asymmetry was highest in the lower anal sphincter and lowest in the mid-sphincter. There was a statistically significant relationship between the HPZ and RP (Pearson rho -0.23, p = 0.01), height (Pearson rho 0.22, p = 0.028), and weight (Pearson rho 0.25, p = 0.012). There were no statistically significant correlations between age, height, or weight with RP, SP, or balloon fill volumes. The characteristic appearance of the normal RP and SP was clearly visualized in all patients. Normal 3DARM values for Sri Lankan primigravid mothers have been established. These may be used as reference values by other investigators.