Uterine artery pulsatility index in the first trimester: assessment of intersonographer and intersampling site measurement differences.

OBJECTIVE: To determine intersonographer, intersampling site pulsatility index differences in the ascending branch of the uterine artery (UtA-PI) and their effect on detection rates (DR) for early onset preeclampsia (PE). METHODS: A prospective observational study was conducted including 52 women with singleton viable pregnancy at 11-13 weeks' gestation. Consecutive bilateral UtA-PI measurements were performed by two sonographers. Both sonographers hold the Fetal Medicine Foundation (FMF) uterine artery Doppler assessment competency certificates. Sonographer "A" underwent mentorship-based specialist training at the FMF; whilst sonographer "B" is a fetal maternal specialist who was deemed competent to measure UtA-PI based on completion of the FMF online course. Both sonographers were unaware of each other's UtA-PI and peak systolic velocity (PSV) measurements throughout the study. UtA-PI was measured by sonographer "A" at 1, 2 and 3 cm distally from the internal os. UtA-PI minimum ("Low-PI") and mean ("Mean-PI") were determined. Intraclass correlation (ICC), Bland-Altman analysis and Wilcoxon signed rank test were performed to determine bias, 95% limits of agreement (LOA) for intersonographer and intersampling site differences. Simulation studies were performed to determine the effect on early onset PE screening DR. RESULTS: (1) Intersite assessment indicated that UtA-PI and PSV decreased by 7-8% per centimeter relative to the measurement taken at the internal os; (2) Sonographer "B" UtA-PI measurements were significantly lower than those of sonographer "A" for "Low-PI" (p = .001), "Mean-PI" (p = .002) and PSV (p = .004) determined by Wilcoxon signed rank test. The mean reduction in "Low-PI", "Mean-PI" and PSV of sonographer "B" relative to sonographer "A" were 14.04%, 11.09% and 10.99%, respectively; (3) Measurements taken by sonographer "B" at the level of the internal os were comparable to measurements taken by sonographer "A" at 2 cm distal to the internal os (low-PI: p = .98, Mean-PI: p = .49 and PSV: p = .24); (4) Between sonographer ICC for UtA-PI was asymmetrical strong (left ICC = 0.72, 95%CI: 0.51-0.84) to fair (right ICC = 0.38, 95%CI: -0.08-0.64); and (5) The 14% mean intersonographer difference in lowest UtA-PI would have resulted in an 7% difference in PE screening performance. CONCLUSIONS: The measurement of UtA-PI is sampling site dependent with the potential for significant intersonographer differences despite the availability of a prescriptive measurement protocol. This is an important observation as it implies that sonographer "B" inadvertently measured the UtA-PI at a distal site, not at the level of internal os, compared to those measured by sonographer "A", resulting in a lower DR for early onset PE.

Parental decisions following prenatal diagnosis of sex chromosome aneuploidy in Hong Kong.

AIM: According to the published work, pregnancy termination rates due to prenatal diagnosis of fetal sex chromosome aneuploidies (SCA) vary widely. Some potentially modifiable and non-modifiable factors have been reported to be associated with parental decision. This study aimed to evaluate the rate of pregnancy termination for fetal SCA and the factors influencing parents' decisions in Hong Kong. METHODS: This was a 21-year retrospective cohort study of parents' decisions following prenatal diagnosis of SCA. Univariate and multivariate analyses for the association between demographic factors, prenatal factors, or counseling provided and decision-making were conducted. RESULTS: The study included 399 pregnancies with prenatal diagnosis of SCA and the overall termination rate was 55.6% (91.7%, 48.0%, 23.4%, 4.8%, and 22.7% for 45,X, 47,XXY, 47,XXX, 47,XYY, and mosaicism, respectively). Pregnancies with ultrasound abnormalities were associated with higher termination rates than pregnancies with normal ultrasound findings (91.3% vs 28.3%, P < 0.0001). From multivariate regression analysis on 226 pregnancies with normal ultrasound examination, a higher likelihood to terminate was found in pregnancies affected by 45,X and 47,XXY (adjusted odds ratio, 4.72, P < 0.0001). Increased maternal age and history of infertility were associated with lower likelihood to terminate (adjusted odds ratio, 0.9, P = 0.012; and 5.12, P = 0.038, respectively). The pregnancy termination rate declined over time. CONCLUSION: A significant correlation was found between the termination of SCA-affected pregnancy and the presence of fetal sonographic abnormalities, type of SCA, maternal age, and presence of infertility.