Background: To determine normal physiologic changes in the uteroplacental hemodynamics during early placental development in the first trimester of pregnancy. Methods: Sixteen normal singleton pregnancies were included in this longitudinal study. Transvaginal Doppler ultrasonographic examinations of uterine, arcuate, radial and spiral arteries were performed at the 5th, 7th, 8th and 10th completed gestational weeks. Peak systolic velocity (PSV), time-averaged maximum velocity (TAMXV) and the pulsatility index (PI) were measured. Results: Uterine artery PSV, TAMXV and PI remained unchanged from the 5th to the 8th week of gestation. From the 8th to the 10th week, PSV (p = 0.02) and TAMXV (p = 0.005) increased and PI decreased (p = 0.006). Changes in the arcuate arteries were similar to those in uterine arteries. No significant changes in PSV, TAMXV or PI of the radial artery were noticed. Spiral artery PSV (p = 0.02) and TAMXV (p = 0.02) increased from the 5th to the 7th week. Thereafter they remained unchanged. Spiral artery PI decreased from the 5th to the 10th week, (p = 0.004). Throughout the study period, the PSV, TAMXV and PI values were significantly higher in the uterine artery than in the arcuate artery, and in the arcuate artery compared with the radial artery. At the 5th gestational week, no differences in PSV and TAMXV were found between radial and spiral arteries. From the 7th gestational week onwards, PSV and TAMXV were significantly lower in the radial artery than in the spiral artery. However, the PI values in the radial artery were significantly higher compared with those in the spiral artery during the whole study period. Conclusions: Spiral artery impedance decreases and blood flow velocities increase as early as between the 5th and the 7th weeks of gestation. During that period, the uterine and arcuate artery hemodynamics remain unchanged. In the uterine and arcuate arteries, decreases in impedance and increases in absolute velocities are detected after the 8th week of gestation. This delay between the changes in the spiral and uterine arteries may represent the magnitude of the increase of placental volume and spiral arterial involvement which is needed to affect uterine hemodynamics.

The intraobserver reproducibility of the pulsatility index (PI), resistance index (RI) and maximum peak systolic velocity (MPSV) measurements in uterine and intraovarian arteries was assessed in ten regularly menstruating women by means of transvaginal pulsed Doppler ultrasound. Three different sources of variation in repeat measurements, i.e. beat-to-beat, between-frame and temporal variability, were studied using the coefficient of variation (CV) and intra-class correlation coefficients. Beat-to-beat and between-frame variabilities in all Doppler parameters were negligible. The following figures were obtained from the assessment of temporal variability. The uterine artery PI and MPSV measurements had a CV of 10% and 15%, respectively. Intra-class correlation coefficients for these parameters were 0.99 and 0.88, respectively. In the intraovarian arteries, the CV was between 15 and 19% for the PI and between 8 and 12% for the RI. The CV values for intraovarian MPSV measurements were 14 and 16%. In contrast, the intra-class correlation coefficients for the intraovarian MPSV measurements showed considerable variation, from 0.63 to 0.68. Uterine artery Doppler velocimetry proved to be a reliable method. The PI and RI measurements in the intraovarian arteries were also reproducible. In contrast, the inconsistency observed in velocity measurements in the intraovarian arteries raises some doubt as to the reliability of these measurements.

Consecutive obese (n = 53) and non-obese parturients (n = 609) were prospectively evaluated during labour to analyse the influence of maternal obesity on labour pain and outcome. Excessive pre-pregnancy weight was classified as a body mass index of 30 kg.m-2 or more. Pain intensity was measured using an 11 point visual scoring scale. Obese parturients had more complicated pregnancies (hypertension and diabetes) and their babies weighed significantly more (3865 g versus 3592 g, p < 0.001). These differences did not affect labour pain experience, or the duration or mode of delivery. Eighty-five percent of the obese parturients and 83% of the controls had high maximal pain scores during the first stage (> 7). Both groups received similar analgesia. More technical problems (p = 0.03) were experienced in establishing epidural analgesia for obese parturients, but this did not influence the success of pain treatment. After delivery, obese women were significantly more content with the pain relief received; only 12% vs 23% in the control group complained of poor pain control (p = 0.03). In this study, obesity and increased fetal size did not complicate labour or its outcome. Critical patient assessment should be emphasised, however, due to the physiological and medical problems present in obese parturients.

Perinatal aspects of pregnancy complicated by fetal ovarian cyst 13(1985)245

Umbilical vein blood flow (UVBF) was studied during the last 24 h before delivery using a combination of real-time and Doppler ultrasonic equipment in 64 normal and pathological pregnancies and the results were correlated with the values of whole blood viscosity taken from the umbilical vein after delivery. UVBF was reduced in the subgroup with chronic fetal distress (n = 14) (P less than 0.001) and the hypertensive pregnancies (n = 17) (P less than 0.05), whereas umbilical blood viscosity was increased only in the subgroup with chronic fetal distress (P less than 0.01) as compared with the normal pregnancies (n = 24). A significant positive correlation was observed between the umbilical blood viscosity and haematocrit values in all the groups of patients. UVBF and blood viscosity had a significant negative correlation in chronic fetal distress (P less than 0.001) and in hypertensive pregnancies (P less than 0.05), but not in normal or diabetic pregnancies (n = 9). Thus haemoconcentration leading to increased fetal blood viscosity may act as an aetiological factor in the reduction of UVBF in developing fetal distress.