Timing of induction of labor in suspected macrosomia: retrospective cohort study, systematic review and meta-analysis.

OBJECTIVE: Large-for-gestational-age (LGA) is associated with several adverse maternal and neonatal outcomes. Although many studies have found that early induction of labor (eIOL) in LGA reduces the incidence of shoulder dystocia (SD), no current guidelines recommend this particular strategy, due to concerns about increased rates of cesarean delivery (CD) and neonatal complications. The purpose of this study was to assess whether the timing of IOL in LGA fetuses affects maternal and neonatal outcomes in a single center; and to combine these results with the evidence reported in the literature. METHODS: This study comprised two parts. The first was a retrospective cohort study that included: consecutive patients with singleton pregnancy, an estimated fetal weight (EFW) ≥90th percentile on ultrasound (US) between 35+0 and 39+0 weeks of gestation (WG), who were eligible for normal vaginal delivery. The second part was a systematic review of literature and meta-analysis that included the results of the first part as well as all previously reported studies that have compared IOL to expectant management in patients with LGA. The perinatal outcomes were CD, operative vaginal delivery (OVD), SD, brachial plexus palsy, anal sphincter injury, postpartum hemorrhage (PPH), APGAR score, umbilical arterial pH, neonatal intensive care unit (NICU) admission, use of continuous positive airway pressure (CPAP), intracranial hemorrhage (ICH), phototherapy, and bone fracture. RESULTS: Retrospective cohort: of the 547 patients, 329 (60.1%) were induced and 218 (39.9%) entered spontaneous labor. Following covariate balancing, CD was significantly higher in the IOL group in comparison to the spontaneous labor group. This difference only became apparent beyond 40WG (hazard ratio: 1.9, p=0.030). The difference between both groups for shoulder dystocia was not statistically significant. Systematic review and metanalysis: 17 studies were included in addition to our own results giving a total sample size of 111,300 participants. When IOL was performed <40+0WG, the risk for SD was significantly lower in the IOL group (OR: 0.64, 95%CI: 0.42-0.98, I2 =19%). There was no significant difference in CD rate between IOL and expectant management after pooling the results of these 17 studies. However, when removing the studies in which IOL was done exclusively before 40+0WG, the risk for CD in the remaining studies (IOL not exclusively <40+0WG) was significantly higher in the IOL group (odds ratio [OR]: 1.46, 95% confidence interval [95%CI]: 1.02-2.09, I2 =56%). There were no statistically significant differences between IOL and expectant management for the remaining perinatal outcomes. Nulliparity, history of CD, and low Bishop score but not methods of induction were independent risk factors for intrapartum CD in patients who were induced for LGA. CONCLUSION: Timing of IOL in patients with suspected macrosomia significantly impacts perinatal adverse outcomes. IOL has no impact on rates of SD but does increase CD when considered irrespective of gestational age, but it may decrease the risk of SD without increasing the risk of other adverse maternal outcomes, in particular cesarean section when performed before 40+0 WG. (GRADE: Low/Very low). This article is protected by copyright. All rights reserved.

Prediction of large-for-gestational age at 36 weeks' gestation: two-dimensional ultrasound vs three-dimensional ultrasound vs magnetic resonance imaging.

OBJECTIVE: To compare the performance of two-dimensional ultrasound (2D-US), three-dimensional ultrasound (3D-US) and magnetic resonance imaging (MRI) at 36 weeks' gestation in predicting the delivery of a large-for-gestational-age (LGA) neonate, defined as birth weight ≥ 95th percentile, in patients at high and low risk for macrosomia. METHODS: This was a secondary analysis of a prospective observational study conducted between January 2017 and February 2019. Women with a singleton pregnancy at 36 weeks' gestation underwent 2D-US, 3D-US and MRI within 15 min for estimation of fetal weight. Weight estimations and birth weight were plotted on a growth curve to obtain percentiles for comparison. Participants were considered high risk if they had at least one of the following risk factors: diabetes mellitus, estimated fetal weight ≥ 90th percentile at the routine third-trimester ultrasound examination, obesity (prepregnancy body mass index ≥ 30 kg/m2) or excessive weight gain during pregnancy. The outcome was the diagnostic performance of each modality in the prediction of birth weight ≥ 95th percentile, expressed as the area under the receiver-operating-characteristics curve (AUC), sensitivity, specificity and positive and negative predictive values. RESULTS: A total of 965 women were included, of whom 533 (55.23%) were high risk and 432 (44.77%) were low risk. In the low-risk group, the AUCs for birth weight ≥ 95th percentile were 0.982 for MRI, 0.964 for 2D-US and 0.962 for 3D-US; pairwise comparisons were non-significant. 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 was noted between MRI and both 2D-US (P = 0.002) and 3D-US (P = 0.002), but not between 2D-US and 3D-US (P = 0.503). In the high-risk group, MRI had the highest sensitivity (65.79%) compared with 2D-US (36.84%, P = 0.002) and 3D-US (21.05%, P < 0.001), whereas 3D-US had the highest specificity (98.99%) compared with 2D-US (96.77%, P = 0.005) and MRI (96.97%, P = 0.004). CONCLUSIONS: At 36 weeks' gestation, MRI has better performance compared with 2D-US and 3D-US in predicting birth weight ≥ 95th percentile in patients at high risk for macrosomia, whereas the performance of 2D-US and 3D-US is comparable. For low-risk patients, the three modalities perform similarly. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Prevalence of and risk factors for failure of fetal magnetic resonance imaging due to maternal claustrophobia or malaise.

OBJECTIVE: To evaluate the prevalence of and risk factors for failure of fetal magnetic resonance imaging (MRI) due to maternal claustrophobia or malaise. METHODS: This retrospective cohort study included pregnant women who underwent fetal MRI for clinical indications or research purposes between January 2012 and December 2019 at a single center. One group included patients who completed the entire examination and the other group inlcuded patients who interrupted their MRI examination due to claustrophobia/malaise. We estimated the rate of MRI failure due to maternal claustrophobia/malaise and compared maternal and clinical variables between the two groups. Multiple logistic regression analysis was performed to identify independent risk factors for claustrophobia/malaise during MRI examination in pregnancy. RESULTS: Among 3413 patients who agreed to undergo fetal MRI, the prevalence of failure because of claustrophobia or malaise was 2.1%. The rate of claustrophobia/malaise in patients who underwent MRI for a clinical indication was lower compared to that in patients who underwent MRI for research purposes only (0.6% (4/696) vs 2.4% (65/2678); P = 0.003). Fetal MRI performed for research purposes only (adjusted odds ratio (aOR), 0.05 (95% CI, 0.01-0.48); P = 0.003), higher maternal age (aOR, 1.07 (95% CI, 1.02-1.12); P = 0.003) and later gestational age at the time of fetal MRI (aOR, 1.46 (95% CI, 1.16-2.04); P = 0.008) were independent risk factors for claustrophobia/malaise. Shorter fetal MRI duration (aOR, 0.77 (95% CI, 0.63-0.88); P = 0.001) was also associated with claustrophobia/malaise during the procedure. Body mass index, ethnic origin, multiple pregnancy, being parous and size of the magnetic bore were not associated with MRI failure due to claustrophobia/malaise. CONCLUSION: The rate of fetal MRI failure due to claustrophobia or malaise was found to be low, particularly when the examination was performed for a clinical indication, and should not be considered a common problem in the pregnant population. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Magnetic resonance scoring system for assessment of adnexal masses: added value of diffusion-weighted imaging including apparent diffusion coefficient map.

OBJECTIVES: To validate prospectively the ADNEX magnetic resonance (MR) scoring system to assess adnexal masses and to evaluate a new, modified ADNEX MR scoring system that incorporates diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) mapping. METHODS: Between January 2015 and September 2018, 323 consecutive women with adnexal masses diagnosed on transvaginal ultrasound (TVS) underwent standardized MR imaging (MRI) including diffusion and dynamic contrast-enhanced sequences. Of these, 131 underwent subsequent surgery. For interpretation of the MRI examinations, we applied the five-category ADNEX MR scoring system, along with a modified scoring system including DWI with ADC mapping. For both scoring systems, a score was given for all adnexal masses. Histological diagnosis was considered as the gold standard and lesions were classified as benign or malignant. The difference between the predictive values for diagnosing malignancy of the classical and modified scoring systems was assessed on the basis of the areas under the receiver-operating-characteristics (AUC) curves. The sensitivity and specificity for diagnosing malignancy of each score were also calculated. RESULTS: Among the 131 women with adnexal mass(es) diagnosed on TVS who underwent MRI and subsequent surgery, the surgery revealed 161 adnexal masses in 126 women; five women had no mass. Histological examination confirmed 161 adnexal masses, of which all had been detected on MRI: 32 malignant tumors, 15 borderline tumors, which were classified as part of the malignant group (n = 47), and 114 benign lesions. The AUC for prediction of a malignant lesion was 0.938 (95% CI, 0.902-0.975) using the classical ADNEX MR scoring system and 0.974 (95% CI, 0.953-0.996) using the modified scoring system. Pairwise comparison of these AUCs revealed a significant difference (P = 0.0032). The sensitivity and specificity for diagnosing malignancy with an ADNEX MR score of 4 or more were 95.5% and 86.6%, respectively, using the classic scoring system, and 95.7% and 93.3%, respectively, using the modified scoring system. CONCLUSION: DWI with ADC mapping could be integrated into the ADNEX MR scoring system to improve specificity, thereby potentially optimizing clinical management by avoiding unnecessary surgery. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

Postmortem fetal imaging: prospective blinded comparison of two-dimensional ultrasound with magnetic resonance imaging.

OBJECTIVE: To compare the diagnostic rate and accuracy of 3-Tesla (T) postmortem magnetic resonance imaging (PM-MRI) and postmortem ultrasound (PM-US) in an unselected fetal population. METHODS: We performed prospectively, in a blinded manner, 3-T PM-MRI and PM-US on 160 unselected fetuses at 13-41 weeks of gestation. All imaging was reported according to a prespecified template, for five anatomical regions: brain, thorax, heart, abdomen and spine. The rates of non-diagnostic results for PM-US and PM-MRI were compared and, for results that were diagnostic, we calculated sensitivity, specificity and concordance rates for each anatomical region, using conventional autopsy as the reference standard. RESULTS: 3-T PM-MRI performed significantly better than did PM-US overall and in particular for fetuses ≥ 20 weeks' gestation. Specifically, the non-diagnostic rates for PM-MRI vs PM-US were 4.4% vs 26.9% (7/160 vs 43/160; P < 0.001) for the brain, 5.2% vs 17.4% (8/155 vs 27/155; P < 0.001) for the thorax, 3.8% vs 30.6% (6/157 vs 48/157; P < 0.001) for the heart and 3.2% vs 23.6% (5/157 vs 37/157; P < 0.001) for the abdomen. For the spine, both techniques showed an equally low non-diagnostic rate. When both postmortem imaging techniques were diagnostic, they had similar accuracy, with no difference in sensitivity or specificity, and similar concordance with autopsy (PM-US, 79.5-96.5%; PM-MRI, 81.6-99.1%). CONCLUSIONS: PM-MRI performed significantly better than PM-US in this unselected population, due mainly to a lower non-diagnostic rate. PM-MRI should remain the first-line imaging investigation for perinatal autopsy, but PM-US could be considered if MRI is not available, albeit with a higher non-diagnostic rate. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Postmortem examination of human fetuses: comparison of two-dimensional ultrasound with invasive autopsy.

OBJECTIVE: To assess the diagnostic accuracy of postmortem ultrasound performed by operators blinded to prenatal findings and to invasive autopsy results in fetuses at different gestational ages and to investigate the effect of various parameters on its diagnostic success. METHODS: We performed postmortem two-dimensional ultrasound examination, blinded to clinical details, on 163 fetuses at 13-42 weeks' gestation. Logistic regression analysis was used to investigate the effect of: (i) gestational age at postmortem ultrasound, (ii) presence of maceration and (iii) mode of death, on whether the exam succeeded or failed to reach a diagnosis. In 123 cases in which invasive autopsy was available, the diagnostic accuracy of ultrasound in detecting major organ abnormalities was evaluated, using invasive autopsy as the gold standard. RESULTS: For the fetal brain, postmortem ultrasound exam was non-diagnostic in significantly more fetuses with maceration (39.5%; 17/43) vs those without maceration (20.0%; 24/120) (P = 0.013). For the fetal thorax, the exam was non-diagnostic in 34.1% (15/44) of fetuses < 20 weeks of gestation and in 10.9% (13/119) of fetuses ≥ 20 weeks (P < 0.001). For the heart and abdominal organs, there was no association between non-diagnostic postmortem ultrasound and the variables tested. For fetuses < 20 weeks, specificity of postmortem ultrasound examination was 83.3% for detection of anomalies of the brain, 68.6% for the thorax and 77.4% for the heart. For fetuses ≥ 20 weeks, sensitivity and specificity were, respectively, 61.9% and 74.2% for detection of anomalies of the brain, 29.5% and 87.0% for the thorax and 65.0% and 83.1% for the heart. For the fetal abdominal organs, sensitivity was 60.7% and specificity 75.8%, and postmortem ultrasound was particularly useful for detection of abnormalities of the kidneys, irrespective of gestational age. CONCLUSION: Although maceration may lead to failure of postmortem ultrasound examination in some cases, this technique achieves diagnostically acceptable levels of accuracy for fetal brain and abdominal organs, compared with conventional autopsy. It may therefore play a role as a first-line examination before other virtual autopsy techniques are indicated. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Prenatal prediction of postnatal large-for-dates neonates using a simplified MRI method: comparison with conventional 2D ultrasound estimates.

OBJECTIVE: To evaluate the performance of a simple semi-automated method for estimation of fetal weight (EFW) using magnetic resonance imaging (MRI) as compared with two-dimensional (2D) ultrasound (US) for the prediction of large-for-dates neonates. METHODS: Data of two groups of women with singleton pregnancy between March 2011 and May 2016 were retrieved from our database and evaluated retrospectively: the first group included women who underwent US-EFW and MRI-EFW within 48 h before delivery and the second group included women who had these evaluations between 35 + 0 weeks and 37 + 6 weeks of gestation, more than 48 h before delivery. US-EFW was based on Hadlock et al. and MRI-EFW on the formula described by Baker et al. For MRI-EFW, planimetric measurement of the fetal body volume (FBV) was performed using a semi-automated method and the time required for measurement was noted. Outcome measure was the performance of MRI-EFW vs US-EFW in the prediction of large-for-dates neonates, both ≤ 48 h and > 48 h before delivery. Receiver-operating characteristics (ROC) curves for each method were compared using the DeLong method. RESULTS: Of the 270 women included in the first group, 48 (17.8%) newborns had birth weight ≥ 90th centile and 30 (11.1%) ≥ 95th centile. The second group included 83 women, and nine (10.8%) newborns had birth weight ≥ 95th centile. Median time needed for FBV planimetric measurements in all 353 fetuses was 3.5 (range, 1.5-5.5) min. The area under the ROC curve (AUC) for prediction of large-for-dates neonates by prenatal MRI performed within 48 h before delivery was significantly higher than that by US (for birth weight ≥ 90th centile, difference between AUCs = 0.085, standard error (SE) = 0.020, P < 0.001; for birth weight ≥ 95th centile, difference between AUCs = 0.036, SE = 0.014, P = 0.01). Similarly, MRI-EFW was better than US-EFW in predicting birth weight ≥ 95th centile when both examinations were performed > 48 h prior to delivery (difference between AUCs = 0.077, SE = 0.039, P = 0.045). CONCLUSION: MRI planimetry using our purpose-designed semi-automated method is not time-consuming. The predictive performance of MRI-EFW performed immediately prior to or remote from delivery is significantly better than that of US-EFW for the prediction of large-for-dates neonates. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

[Physiological hydronephrosis in pregnancy: Occurrence and possible causes. An MRI study]. / L'hydronéphrose physiologique durant la grossesse : prévalences et causes possibles. Une étude basée sur l'IRM.

INTRODUCTION: The etiology of the uretero-hydronephrosis in pregnancy is just hypothesis: hormonal or mechanical hypothesis, only investigated by echographic studies. MRI permits to visualize the entirety of the urinary tract, which can be helpful to find out a mechanical cause. METHODOLOGY: We have analysed the MRI of 100 asymptomatic pregnant women. We have determined the number and locations of the uretero-hydronephroses and researched whether there is any relationship between the uretero-hydronephrosis and certain abdominal structures. We focused on the psoas muscle and measured its depth, width and calculated its surface by a reproducible method. RESULTS: The analysis revealed that the uretero-hydronephrosis was predominantly at the right side (63%) and in the majority of the cases limited to the kidney (42%) and/or the proximal third of the ureter (42%). We were able to rule out some proposed etiologies: a compression of the ureter between the uterus and the iliac or ovarian vessels; a protective effect of the left intestinal structures. A link was observed between the psoas muscle and the physiological uretero-hydronephrosis: the ipsilateral psoas muscle seemed smaller in pregnant women presenting a uretero-hydronephrosis. CONCLUSION: We have highlighted a link between a physiological uretero-hydronephrosis during pregnancy and a lesser developped psoas muscle. The hypothesis proposed is that a smaller psoas muscle would have a less protective effect of the ureter due to a lesser development. This study offers a practical conclusion: a left sided uretero-hydronephrosis during pregnancy and/or including the entirety of the ureter is more probably a pathological hydronephrosis. LEVEL OF EVIDENCE: 4.

[Recurrence of congenital diaphragmatic hernia]. / Une récidive de hernie diaphragmatique congénitale.

Through the case report of a child who had had a congenital diaphragmatic hernia (cdh) and then relapsed 8 months after initial surgery, the various risk factors related to a cdh, its pre- and postnatal management as well as some long-term complications are discussed.

Par le biais du cas clinique d'un enfant qui a été opéré d'une hernie diaphragmatique congénitale (HDC) et qui a récidivé 8 mois plus tard, les différents facteurs de risques liés à la HDC, sa prise en charge ante et post-natale ainsi que quelques possibles complications à long terme sont discutés.

Osteoid osteoma of the pisiform bone: A rare cause of wrist pain.

Non-traumatic wrist pain remains a diagnostic challenge. An accurate diagnosis is crucial in order to choose the appropriate treatment. We report the case of a 23-year-old female with a four-month history of mainly nocturnal wrist pain. There was no history of trauma or prior surgery. Radiographs and CT scans showed a lytic lesion with central nidus and sclerotic margins in the pisiform bone. Bone scan showed increased uptake in the pisiform bone. The diagnosis of osteoid osteoma was confirmed by histopathological analysis after complete surgical resection. Osteoid osteoma of the carpal bones is a rare cause of wrist pain and can raise diagnostic issues. Diagnosis is based on both clinical and radiological features; histopathological analysis can confirm the diagnosis. Treatment depends on several criteria and multiple options are possible, but surgical excision is often preferred for the wrist. Osteoid osteoma should always be considered in young patients presenting with chronic unexplained wrist pain.

Stomach position in prediction of survival in left-sided congenital diaphragmatic hernia with or without fetoscopic endoluminal tracheal occlusion.

OBJECTIVE: To investigate the value of fetal stomach position in predicting postnatal outcome in left-sided congenital diaphragmatic hernia (CDH) with and without fetoscopic endoluminal tracheal occlusion (FETO). METHODS: This was a retrospective review of CDH cases that were expectantly managed or treated with FETO, assessed from May 2008 to October 2013, in which we graded, on a scale of 1-4, stomach position on the four-chamber view of the heart with respect to thoracic structures. Logistic regression analysis was used to investigate the effect of management center (Paris, Brussels, Barcelona, Milan), stomach grading, observed-to-expected lung area-to-head circumference ratio (O/E-LHR), gestational age at delivery, birth weight in expectantly managed CDH, gestational ages at FETO and at removal and period of tracheal occlusion, on postnatal survival in CDH cases treated with FETO. RESULTS: We identified 67 expectantly managed CDH cases and 47 CDH cases that were treated with FETO. In expectantly managed CDH, stomach position and O/E-LHR predicted postnatal survival independently. In CDH treated with FETO, stomach position and gestational age at delivery predicted postnatal survival independently. CONCLUSION: In left-sided CDH with or without FETO, stomach position is predictive of postnatal survival.

Impact of operator experience on the variability of fetal lung volume estimation by 3D-ultrasound (VOCAL) and magnetic resonance imaging in fetuses with congenital diaphragmatic hernia.

OBJECTIVE: To evaluate the impact of operator experience in volumetric measurements on intra- and inter-observer variability of lung volume estimation by 3-dimensional (3D) ultrasound and magnetic resonance imaging (MRI) in fetuses with congenital diaphragmatic hernia (CDH). METHODS: We conducted a retrospective single-center study. Total fetal lung volume (TFLV) was measured twice using 52 stored 3D-ultrasound volumes and 52 corresponding MRI exams by a fetal medicine specialist with no experience in volumetric measurements and two operators experienced in the respective techniques. Bland-Altman analysis was performed to evaluate intra- and inter-observer variability. RESULTS: Measurements of TFLV by 3D-ultrasound showed higher intra-observer variability compared with MRI irrespective of operator experience, with narrower 95% limits of agreement on MRI as compared with ultrasound measurements. Similarly, 3D-ultrasound showed higher inter-observer variability as compared with MRI. Finally the 95% limits of agreement at ultrasound were quite comparable for intra-observer variability between the experienced and the inexperienced operator. CONCLUSION: Our study shows that operator experience has an impact on the variability of TFLV and, in the absence of experience in volumetric measurements, estimation of TFLV in fetuses with CDH by 3D-ultrasound shows higher variability than MRI measurements, but even in experienced hands variability is greater for 3D-ultrasound.

Bilateral lesions of the globus pallidus in a young woman.

We report a case of stroke due to cocaine abuse in a 30-year-old woman. The initial examinations pointing to this diagnosis were CT and MRI. Magnetic Resonance Imaging revealed bilateral globus pallidus infarction characterized by restricted Diffusion with low ADC values. There was also a partial hemorrhagic component confirmed on T2* sequence. After gadolinium injection there was a ring enhancement consistent with a blood brain barrier leakage. Similar lesions have been described in post hypoxic-anoxic injuries such as following cardiac arrest, severe blood loss and CO intoxication.

Arabin cervical pessary in women at high risk of preterm birth: a magnetic resonance imaging observational follow-up study.

OBJECTIVE: To help elucidate the mechanism of action of the Arabin cervical pessary in pregnancies at high risk for preterm delivery. METHODS: Cervical length and uterocervical angle were evaluated in relation to gestational age in 198 pregnancies not at high risk for preterm birth that underwent clinical fetal magnetic resonance imaging (MRI). Additionally, in 73 singleton pregnancies at high risk for preterm birth, an Arabin cervical pessary was placed at 14-33 weeks' gestation. We performed MRI of the cervix immediately before and after placement and at monthly follow-up until removal of the pessary. In a subgroup of 54 pregnancies with a short cervix and pessary placement at 17-31 weeks' gestation, the uterocervical angle and cervical length at follow-up were compared with the preplacement values. RESULTS: In pregnancies not at high risk for preterm birth, the uterocervical angle did not vary, but cervical length showed a significant decrease with gestational age (r = -0.15, P < 0.05). Among the high-risk patients, the cervical pessary was successfully placed at first attempt in 60 (82.2%) and by the second attempt in 66 (90.4%), remaining well positioned until removal. In five patients we failed to place the pessary after two attempts, in one patient the pessary dislodged during follow-up and in one case the pessary was partly placed in the external cervical canal and triggered labor the next day. Among the subgroup of 54 patients, the median uterocervical angle immediately after pessary placement was significantly more acute than that prior to placement in the 46 (85.2%) who delivered after 34 weeks (132° vs 146°, P < 0.01), but was unchanged in the eight patients who delivered before 34 weeks (143° vs 152°, P > 0.05). CONCLUSION: In patients at high risk for preterm delivery, correct placement of the Arabin cervical pessary should be checked immediately; this can be performed quickly and easily using MRI. This study provides some evidence that, in singleton pregnancies with a short cervix, a cervical pessary delays birth through a mechanical effect on the uterocervical angle.

Determination of fetal body volume measurement at term with magnetic resonance imaging: effect of various factors.

PURPOSE: To evaluate various factors that potentially influence the fetal body volume (FBV) measurement using magnetic resonance imaging (MRI) and to analyze whether the technique of measurement could be simplified. MATERIALS AND METHODS: In 20 singleton pregnancies scheduled for a planned delivery, FBV measurements were performed by two independent operators on sagittal, axial and coronal planes and with various slice thickness and intersection gap, totalizing 100 examinations. MR estimation of fetal weight (MR-EFW) was calculated based on the equation developed by Baker. The relative error of MR-EFW was calculated in function of birth weight (BW). Regression analysis was used to investigate the effect on the relative error of MR-EFW of different variables but also to investigate the effect on the measurement time of the FBV of various factors. RESULTS: The mean relative error of MR-EFW was 1.96% and was significantly associated only with patient's BMI but not with the type of MR sequence used or other variables. Type of MR sequence used and BW were significantly associated with the measurement time of FBV. CONCLUSION: Using MRI, the time for FBV measurement can be significantly reduced using thicker slices or intersection gap, with similar accuracy.