RESUMEN
OBJECTIVES: This study aimed to establish reference values for fetal aortic isthmus blood flow velocity and associated indices during the first trimester, utilizing a novel ultrasonographic technique known as high-definition flow imaging (HDFI). Additionally, the correlation between Doppler profiles of aortic blood flow and key fetal parameters, including nuchal thickness (NT), crown-rump length (CRL), and fetal heartbeat (FHB), was investigated. METHODS: A total of 262 fetuses were included in the analysis between December 2022 and December 2023. Utilizing 2D power Doppler ultrasound images, aortic blood flow parameters were assessed, including aortic peak systolic velocity (PS), aortic end-diastolic velocity (ED), aortic time average maximal velocity (TAMV), and various indices such as aortic systolic velocity/diastolic velocity (S/D), aortic pulsatile index (PI), aortic resistance index (RI), aortic isthmus flow velocity index (IFI), and aortic isthmic systolic index (ISI). Concurrently, fetal FHB, NT, and CRL were evaluated during early trimester Down syndrome screening. RESULTS: Significant findings include a positive correlation between gestational age (GA) and PS (PS = 3.75 × (GA) - 15.4, r2 = 0.13, p < 0.01), ED (ED = 0.42 × (GA) - 0.61, r2 = 0.04, p < 0.01), PI (PI = 0.07 × (GA) + 1.03, r2 = 0.04, p < 0.01), and TAMV (TAMV = 1.23 × (GA) - 1.66, r2 = 0.08, p < 0.01). In contrast, aortic ISI demonstrated a significant decrease (ISI = -0.03 × (GA) + 0.57, r2 = 0.05, p < 0.05) with gestational age. No significant correlation was observed for aortic RI (p = 0.33), S/D (p = 0.39), and IFI (p = 0.29) with gestational age. Aortic PS exhibited positive correlations with NT (0.217, p = 0.001) and CRL (0.360, p = 0.000) but a negative correlation with FHB (-0.214, p = 0.001). Aortic PI demonstrated positive correlations with CRL (0.208, p = 0.001) and negative correlations with FHB (-0.176, p = 0.005). Aortic TAMV showed positive correlations with NT (0.233, p = 0.000) and CRL (0.290, p = 0.000) while exhibiting a negative correlation with FHB (-0.141, p = 0.026). Aortic ISI demonstrated negative correlations with NT (-0.128, p = 0.045) and CRL (-0.218, p = 0.001) but a positive correlation with FHB (0.163, p = 0.010). CONCLUSIONS: Power Doppler angiography with Doppler ultrasound demonstrates the ability to establish accurate reference values for fetal aortic blood flow during the first trimester of pregnancy. Notably, aortic PS, TAMV, and ISI exhibit significant correlations with NT, CRL, and FHB, with ISI appearing more relevant than IFI, PS, TAMV, and FHB. The utilization of HDFI technology proves advantageous in efficiently detecting the site of the aortic isthmus compared to traditional color Doppler mode in early second trimesters.
RESUMEN
PURPOSE: We aimed to assess risk factors for dystocia-related cesarean section (CS) in uncomplicated Taiwanese nulliparas at term METHODS: We reviewed 1,272 deliveries by 1 obstetrician in a Taiwanese hospital between February 2004 and December 2011. These parturients were nulliparas with singleton pregnancies ≥ 37 weeks gestation who had liveborn cephalic deliveries. The CS group consisted of parturients with dystocia-related CS for the following indications: prolonged latent phase, failure to progress, or arrest of descent. Eight confounding variables [maternal age, height, weight, body mass index (BMI) in labor, gestational age, infant birth weight, gender, and cervical dilatation] were obtained from the medical records. Multivariate logistic regression analysis was used to determine the association between each variable and route of delivery. A predictive formula for CS probability was generated using a logistic regression model. RESULTS: Overall 15.0 % of nulliparas in our population underwent CS. Logistic regression analysis revealed a significant association between maternal BMI and CS (adjusted OR 1.112; 95 % CI 1.065-1.161; P < 0.001). The association between maternal age and CS was also statistically significant (adjusted OR 1.074, 95 % CI 1.033-1.116, P = 0.001). Maternal height, weight in labor, gestational age, infant birth weight, gender, and cervical dilatation were not significantly associated with the route of delivery. A predictive formula for CS probability was developed based on a combination of maternal BMI and age. CONCLUSIONS: Our results show that maternal age and BMI in labor are significantly associated with dystocia-related CS in uncomplicated Taiwanese nulliparas at term. We develop a practical formula to predict the probability for CS. Using this formula, obstetricians can estimate the risk of CS according to maternal age and BMI in labor.
