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Prediction of large-for-gestational age at 36 weeks’ gestation: two-dimensional vs three-Dimensional vs magnetic resonance imaging

Ultrasound Obstet Gynecol. 2023 Sep 19. doi: 10.1002/uog.27485. Online ahead of print.


OBJECTIVE: To compare the performance of two-dimensional ultrasound (2D-US) three-dimensional ultrasound (3D-US) and magnetic resonance imaging (MRI) at 36 weeks of gestation (WG) in the prediction of Large-for-Gestational-Age (LGA) fetuses defined as birthweight > 95th percentile in a high- and low-risk groups for macrosomia.

METHODS: This was a prospective observational study conducted between January 2017 and February 2019. Women with singleton pregnancy at 36 WG underwent simultaneously 2D-US, 3D-US, and MRI. By plotting the weight estimations and the birthweight on the growth curve, a percentile was obtained, and it was used for comparison. The study population was divided into high- and low-risk groups, according to at least one of the following risk factors: the presence of diabetes, suspicion of macrosomia during the third trimester (> 90th percentile at the ultrasound routine scan), obesity (body mass index, BMI, > 30 kg/m2 ), and excessive weight gain. The outcome was the measurement of the performance of each diagnostic modality in the prediction of birthweight > 95th percentile. Statistical analysis was performed by calculating the area under the receiver operating characteristic (ROC) curve (AUC), sensitivity, specificity, positive and negative predictive values for each modality.

RESULTS: Out of 988 patients, 965 were eligible: 533 (55.23%) in the high-risk group and 432 (44.77%) in the low-risk group. In the low-risk group, the AUCs were 0.982 for MRI, 0.964 for 2D-US, and 0.962 for 3D-US. No statistical significance was found among these three methods. In the high-risk group, the AUCs were 0.959 for MRI, 0.909 for 2D-US, and 0.894 for 3D-US. A statistically significant difference between MRI and both 2D-US (p = 0.002) and 3D-US (p = 0.002) was found. MRI had the highest sensitivity (65.79%) compared with both 2D-US (36.84%) and 3D-US (21.05%) ultrasound (p = 0.002 and p < 0.001, respectively). The 3D-US had the highest specificity (98.99%) compared to both methods (2D-US: 96.77%, p = 0.005, and MRI: 96.97%, p = 0.004).

CONCLUSION: At 36 WG, MRI performs better than 2D-US and 3D-US in predicting birthweight > 95th percentile at birth, especially in patients at high-risk for macrosomia, while 2D-US and 3D-US are comparable. For low-risk patients, the three modalities perform similarly. This article is protected by copyright. All rights reserved.

PMID:37725758 | DOI:10.1002/uog.27485

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