The dynamic characteristics of the circumvaginal muscles.

Circumvaginal muscle (CVM) maximum pressure was studied as related to the postpartal period, parity, type of birth, episiotomy, age, breastfeeding, physical activity, body mass, stress urinary incontinence, and orgasm in a sample of 98 healthy postpartal and nonpostpartal women. Circumvaginal muscle pressure tracings were obtained from these women using a pressure-sensitive, intravaginal balloon device. Correlations between circumvaginal muscle maximum pressures and episiotomy, age, breastfeeding, physical activity, body mass, stress urinary incontinence, and orgasm were either not significant or only weakly significant. However, Duncan's multiple range test showed differences in the maximum pressures between groups (nulliparous, parity greater than 0, cesarean delivery, and vaginal delivery) and indicated that vaginal birth has a marked weakening effect on the circumvaginal muscles.

Reliability of urine temperature as a measurement of basal body temperature.

Natural family planning is based on the recognition of physiologic signs and symptoms that identify fertile and infertile phases of the menstrual cycle. Identification of the onset of the infertile period can be determined when the upward shift in basal body temperature (BBT) has occurred. A study was conducted to determine if the temperature of the first-morning voided urine adequately represents BBT. In 22 subjects, vaginal temperature, taken immediately upon awakening, was compared with first-morning voided urine temperature as measured continuously by thermocouples mounted in either of two flow-through devices attached to a toilet bowl. A significant correlation was found between the two temperatures. The convenience and hygiene of the method together with the reliability of urine temperature as an estimator of BBT could reduce the generally high rate of noncompliance of women choosing this natural method of family planning.