CHANGES IN UTERINE ARTERY RESISTANCE TO BLOOD-FLOW DURING PUERPERIUM - A LONGITUDINAL-STUDY

Objective: A longitudinal study was undertaken to assess the changes i n the resistance of uterine arteries during puerperium. Methods: The u terine arteries of 60 patients with uncomplicated pregnancy and delive ry were examined transvaginally (n = 755) with computerized continuous -wave Doppler. Measurements were taken for the first 3 days after deli very and once a week for the following 8 weeks. The control group cons isted of two subgroups; 1) 201 normal pregnant women at term, and 2) 4 0 nongravid patients. Results: The mean pulsatility index of the first 3 days (1.2 +/- 0.27 to 1.19 +/- 0.36) was significantly higher than that of the 3rd trimester of normal pregnancy (0.77 +/- 0.14). The pul satility index decreased significantly to 1.06 +/- 0.19 in the 2nd pos tpartum week, and remained relatively low until week 4, postpartum (1. 12 +/- 0.19). Thereafter, an increase in pulsatility index was observe d between the 5th and 9th postpartum week. This pulsatility index was still significantly lower than that of the nongravid controls (2.62 +/ - 0.59).Conclusions: Uterine vascular resistance increases soon after delivery. Vascular resistance decreases between the 2nd and 4th weeks postpartum and thereafter increases up to the 9th week without return to the nonpregnant values.