The Use of a Software-Assisted Method to Estimate Fetal Weight at and Near Term Using Magnetic Resonance Imaging.

OBJECTIVE: The aim of this study was to apply a semi-automated calculation method of fetal body volume and, thus, of magnetic resonance-estimated fetal weight (MR-EFW) prior to planned delivery and to evaluate whether the technique of measurement could be simplified while remaining accurate. METHODS: MR-EFW was calculated using a semi-automated method at 38.6 weeks of gestation in 36 patients and compared to the picture archiving and communication system (PACS). Per patient, 8 sequences were acquired with a slice thickness of 4-8 mm and an intersection gap of 0, 4, 8, 12, 16, or 20 mm. The median absolute relative errors for MR-EFW and the time of planimetric measurements were calculated for all 8 sequences and for each method (assisted vs. PACS), and the difference between the methods was calculated. RESULTS: The median delivery weight was 3,280 g. The overall median relative error for all 288 MR-EFW calculations was 2.4% using the semi-automated method and 2.2% for the PACS method. Measurements did not differ between the 8 sequences using the assisted method (p = 0.313) or the PACS (p = 0.118), while the time of planimetric measurement decreased significantly with a larger gap (p < 0.001) and in the assisted method compared to the PACS method (p < 0.01). CONCLUSION: Our simplified MR-EFW measurement showed a dramatic decrease in time of planimetric measurement without a decrease in the accuracy of weight estimates.

The association of first trimester uterine arteries Doppler velocimetry with different clinical phenotypes of hypertensive disorders of pregnancy: a longitudinal study.

Introduction: Current classification of hypertensive disorders of pregnancy (HDP) is mostly based on temporal classification differentiating HDP according to early and late onset of the disease. However, epidemiological and clinical data suggest that there are two different clinical phenotypes of HDP that coexist at any gestational age: HDP associated to intrauterine growth restriction (HDP-IUGR) and HDP associated to appropriate for gestational age fetal growth (HDP-AGAf). The aim of the study was to evaluate the association of first trimester uterine arteries (UtA) by Doppler velocimetry, and maternal risk factors with HDP according to two different classifications: one based on gestational age at delivery (early- and late-HDP), and one based on longitudinal ultrasound evaluation of fetal growth (HDP-IUGR and HDP-AGAf), independently of the gestational age. Methods: Maternal characteristics and mean pulsatility index (PI) of UtA were collected at 11-13 gestational weeks. A longitudinal ultrasound follow-up of fetal growth in each trimester and clinical outcome were obtained in 4290 singleton pregnancies. Results: UtA-PI was significantly higher in women who developed HDP-IUGR (n = 22) and the odds ratio (OR) to develop HDP-IUGR from 25 to 39 weeks was 8.6 (p < .0001). HDP-AGAf (n = 112) was significantly associated with a higher BMI, multiparity, and maternal age, but not with UtA-PI (OR 1.3; p = .2). In women with an abnormal UtA-PI, the odds of developing early (n = 15) and late-HDP (n = 119) were 3.0 (p = .03) and 1.7 (p = .002), respectively. The AUCs for HDP-IUGR and early-HDP were 0.84 and 0.71, respectively. Discussion: UtA Doppler velocimetry in the first trimester was strongly associated with HDP-IUGR all along gestation, as a proxy of placental insufficiency, and showed no association with HDP-AGAf. Our findings suggest an efficacy of first trimester UtA Doppler velocimetry to identify HDP-IUGR independently of the gestational age, and a limited value for HDP not associated with intrauterine growth restriction (IUGR).

Third trimester abdominal circumference, estimated fetal weight and uterine artery doppler for the identification of newborns small and large for gestational age.

OBJECTIVE: To understand if ultrasound biometric evaluation at 30-32 weeks of gestation is a valuable screening tool for the detection of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) infants at birth in a low risk population. STUDY DESIGN: We enrolled 1848 pregnant women with singleton pregnancy undergoing routine fetal biometry. We divided the infants into four groups: moderate SGA, severe SGA, moderate LGA and severe LGA. We considered third-trimester estimated fetal weight (EFW), abdominal circumference (AC), EFW centile (EFWc), AC centile (ACc) and compared their prediction toward SGA and LGA to determine which of these parameters was the best estimator for fetal size. Then we took the strongest predictive value and added all history-related and ultrasound factors to run a stepdown multivariate logistic regression. All the variables were then dichotomized and sensitivity models only for statistically significant parameters were calculated. RESULTS: We identified the following predictive factors for each outcome: for severe SGA: EFWc with p<0.001, uterine artery pulsatility index (UtA PI) with p<0.002. For moderate SGA: EFWc with p<0.001, UtA PI with p<0.004, maternal preeclampsia p<0.002. For moderate and severe LGA: EFWc with p<0.001. CONCLUSION: We can detect in a low-risk population a group at risk of growth deviations. Adding Doppler velocimetry to 30-32 weeks EFWc improves the specificity (84%) regarding SGA newborns, maintaining a good sensitivity (71%), and reducing the population to be re-screened from 27 to 17%. An ultrasound examination at 34-36 weeks or the clinical assessment of maternal risk factors remain the best tools for LGA newborns.