Urodynamic studies in normal pregnancy and in puerperium.

Fourteen primiparas (11 pregnant for the first time, and three with a history of one abortion) were examined during pregnancy to elucidate changes in parameters of importance of maintenance of urinary continence. Urethral pressure profile measurements and simultaneous urethrocystometry were carried out in the beginning of pregnancy (weeks 12 to 16), in the thirty-eighth week, and 5 to 7 days after delivery. Both the absolute and functional lengths of the urethra were found to increase throughout pregnancy by median values of 6.7 and 4.8 mm, respectively. Also, the maximum urethral pressure increased gradually during pregnancy, returning within 1 week after delivery to almost the same value as at the beginning of pregnancy. The urethral closure pressure also increased throughout pregnancy. Thus, the results of the investigation revealed that the physiologic changes which took place within the urethra during pregnancy were to advantage from standpoint of maintaining continence.