[Static closure functional characteristics of lower urinary tract in continence in late pregnancy of primigravida]

To investigate static closure functional characteristics of lower urinary tract in continence in late pregnancy of primigravida through perineal ultrasound and urodynamical measurement.

From January of 2003 to December of 2005, 83 primigravida undergoing antenatal health care in Shanghai Jiaotong University Affiliated Shanghai Sixth People's Hospital were randomly enrolled in the study, while 28 nulliparous women were recruited as control. The perineal ultrasound and urodynamical measurement were performed at the gestation age of 36-40 weeks, in both groups. We analysed the parameters of lower urinary tract function in late pregnancy compared with nullipara, such as maximal urethral closure pressure (MUCP), functional urethral length (FUL), maximal urethral pressure (MUP), valsalva leak point pressure (VLPP), postvoid residual bladder volume (PVRBV) and volume of first desire to voiding (VFDV).

The average weight of 83 neonates was (3504 +/- 404) g. In all of 83 primigravida PVRBV was less than 10 ml. MUP (110 +/- 22) cm H2O (1 cm H2O = 0.098 kPa), MUCP (96 +/- 22)cm H2O and FUL (44 +/- 9) mm were significantly increased in the third trimester compared with nullipara (P < 0.01), but VFDV showed nonsignificant difference (141 +/- 44 vs. 149 +/- 41 ml, P > 0.05). There were 33 pregnant women suffering from urinary leakage throughout the terms. The data showed that MUCP was significantly lower in the pregnant women with symptoms of leaking than without leaking.

the static closure function increased significantly compared with nulliparous women. The VLPP was decreased and had relationship with symptoms of leakage. The results suggest that the function of lower urinary tract in continence in late pregnancy of primigravida is complex.