Antenatal magnetic resonance imaging versus ultrasound for predicting neonatal macrosomia: a systematic review and meta-analysis

BACKGROUND: Fetal macrosomia is associated with an increased risk of adverse maternal and neonatal outcomes. OBJECTIVES: To compare the accuracy of antenatal two-dimensional (2D) ultrasound, three-dimensional (3D) ultrasound, and magnetic resonance imaging (MRI) in predicting fetal macrosomia at birth. SEARCH STRATEGY: Medline (1966-2013), Embase, the Cochrane Library and Web of Knowledge. SELECTION CRITERIA: Cohort or diagnostic accuracy studies of women with a singleton pregnancy, who had third-trimester imaging to predict macrosomia (>4000 g, >4500 g or >90th or >95th centile). DATA COLLECTION AND ANALYSIS: Two reviewers screened studies, performed data extraction and assessed methodological quality. The bivariate model was used to obtain summary sensitivities, specificities and likelihood ratios. MAIN RESULTS: Fifty-eight studies (34 367 pregnant women) were included. Most were poorly reported. Only one study assessed 3D ultrasound volumetry. For predicting birthweight >4000 g or >90th centile, the summary sensitivity for 2D ultrasound (Hadlock) estimated fetal weight (EFW) >90th centile or >4000 g (29 studies) was 0.56 (95% CI 0.49-0.61), 2D ultrasound abdominal circumference (AC) >35 cm (four studies) was 0.80 (95% confidence interval [95% CI] 0.69-0.87) and MRI EFW (three studies) was 0.93 (95% CI 0.76-0.98). The summary specificities were 0.92 (95% CI 0.90-0.94), 0.86 (95% CI 0.74-0.93) and 0.95 (95% CI 0.92-0.97), respectively. CONCLUSION: There is insufficient evidence to conclude that MRI EFW is more sensitive than 2D ultrasound AC (which is more sensitive than 2D EFW); although it was more specific. Further primary research is required before recommending MRI EFW for use in clinical practice

Intrapartum assessment of caput succedaneum by transperineal ultrasound: a two-centre pilot study.

Digital assessments of caput succedaneum are subjective; however, caput succedaneum can also be expressed as ultrasound measured skin-skull distance (SSD). In this study, we aimed to compare the clinical and ultrasound assessment of caput succedaneum (caput) in nulliparous women in the first stage of labour. Furthermore, we aimed to investigate the repeatability of ultrasound measurements. We observed a significant but low correlation between clinical and ultrasound assessments (Kappa value 0.29; P < 0.01). Interobserver repeatability for SSD showed an intraclass correlation coefficient of 0.96 (95% CI, 0.93-0.98). The mean difference for the caput measurements was -0.4 mm (95% CI, -0.85 to 0.05), and limits of agreement were -3.44 to 2.64 mm. We conclude that ultrasound measured SSD is an objective expression of caput with significant correlation with clinical assessment

[Prevention of shoulder dystocia by an ultrasound selection at the beginning of labour of foetuses with large abdominal circumference]

International audienceOBJECTIVE: Prevent shoulder dystocia occuring with macrosomic foetuses, by an ultrasound screening, at the beginning of labour, made by a member of obstetrics staff. MATERIAL AND METHOD: A prospective study in the maternity hospital, la Mère et l'Enfant of University Teaching Hospital, Besançon, about 170 patients. We have measured only one parameter: the foetal abdominal circumference (AC). RESULTS: An AC>or=350 mm had a sensitivity of 100% to detect newborns of birth weight>or=4250 g. CONCLUSION: An AC>or=350 mm measured during labour by a member of obstetrics staff allow to alert and to make the staff sensitive to a risk of macrosomia and shoulder dystocia

[Assisted vaginal delivery using the vacuum extractor in frank breech presentation]

International audienceOBJECTIVES: When all the breech conditions for the acceptance of a vaginal breech birth are present, we occasionally practise a total breech extraction for non frank breech presentations. Similarly, for frank breech presentations, instead of using the fetal leg as tractor, we sometimes apply the vacuum extractor on the breech presentation in order to perform the first step of the total breech extraction. The vacuum extractor is not traumatic for the fetus and enable a quick extraction. This study was conducted to describe the technique we use in our ward. PATIENTS AND METHODS: A retrospective study including every singleton delivery with a breech presentation and a tried and assisted vaginal delivery using the vacuum extractor in our maternity ward from 1994 to 2004. A descriptive analysis of maternal, fetal and obstetrical elements has been carried out. RESULTS: Twenty-eight deliveries were indexed. In each case, a vaginal delivery was performed. Neonatal outcomes were satisfactory with a five minutes Apgar score always higher than 7. In all 96.5% of the extractions were realized under pelvic level +2. The main indication of extraction (78.5%) was a second stage of labour which was too long. CONCLUSION: Obstetricians should know several techniques to accept and to manage breech deliveries. Indications for assisted vaginal delivery using the vacuum extractor in frank breech presentation are unusual, concerning delay in the second stage with an engaged foetus. This technique may avoid some cesarean sections. Nevertheless vaginal breech delivery try should be happening with great caution and with a strict patient's eligibility

[Ultrasound in the diagnosis of fetal head engagement. A preliminary French prospective study]

International audienceOBJECTIVE: The subjectivity and inter- and intra-observer variability of transvaginal (TV) digital examination in the diagnosis of fetal head engagement set a real problem in the strategic choice of the mode of delivery. We conducted a preliminary study on the feasibility of using ultrasound in the diagnosis of fetal head engagement during labour. MATERIAL AND METHOD: From 3rd January to 20th February 2007, a prospective monocentered study was set up by comparing the fetal head position in the pelvic cavity obtained by TV digital examination with the ultrasound measurement of the perineum-fetal head distance. Sixty-five measurements were obtained from 45 patients (single pregnancies, cephalic presentations), during labour and/or at complete cervical dilatation, by a single operator. RESULTS: Whenever the perineum-fetal head distance was greater than 60 mm, the fetal head was not engaged in the pelvic cavity, with a specificity of 89% and a negative predictive value of 94.1%. However, if the distance is less or equal to 60 mm, the fetal head was engaged with a sensitivity of 97.8% and a positive predictive value of 95.6%. It was even possible to define the fetal head station in the cavity as the distances are now known: high cavity : 50 mm, mid cavity : 38 mm, low cavity : 20 mm. CONCLUSION: This technique based on a single distance measurement is not difficult and the reference point is easily localized. An abdominal probe is sufficient, making the diffusion of this method quite easy. With its excellent negative predictive value, transperineal ultrasound would allow obstetricians avoid difficult vaginal extractions, localize correctly the fetal position in the cavity and obtain the exact fetal head orientation, even in case of scalp blood humps. The feasibility and relevance of this technique must be confirmed by larger studies

[Instrumental extractions using Thierry's spatulas: evaluation of the risk of perineal laceration according to occiput position in operative deliveries]

International audienceOBJECTIVE: Risk factors for severe perineal lacerations are nowadays well-known and they include operative vaginal deliveries and extractions in occiput posterior (OP) positions. The aim of this study was to assess whether OP position increases the risk for anal sphincter injury when compared with occiput anterior (OA) positions in operative deliveries using Thierry's spatulas. METHODS: Retrospective study of 163 extractions with Thierry's spatulas over a five-year period (January 2000 to December 2005) performed in a general hospital. Singleton cephalic pregnancies at term were studied and the incidence of severe perineal lacerations was noted in deliveries in OP and OA positions. RESULTS: In these 163 cases, the varieties of presentation obtained by vaginal examination were 129 in anterior and 34 in posterior positions. Eleven posterior positions rotated anteriorly on delivery and 23 remained in a posterior position. The OA group (n=140) and the OP group (n=23) were constituted. Anal sphincter injury occurred significantly more often in the OP group compared with the OA group (17.4% versus 2.9%, p=0.014) with an odds ratio of 7.1 (95% CI 1.6-31). Only one fourth-degree laceration was noted. Within the OP group, the incidence of vaginal lacerations was increased compared to the OA group, but without any significant difference (43.5% versus 27.9%, p=0.20). In a logistic regression model, the OP position was 6.4 times (95% CI 1.3-31.5) more likely to be associated with anal sphincter injury than OA position. The incidence of OP position was 14.1% within the whole population studied and Thierry's spatulas permit anterior rotations of occipito posterior presentation in only 32.4% of cases. CONCLUSION: The efficiency of Thierry's spatulas is proven. As with forceps and vacuum extractors, extraction with Thierry's spatulas is a risk factor for perineal laceration compared to a spontaneous delivery. In deliveries with spatulas, OP head positions further increase this perineal risk against OA positions. OP positions before fetal extractions do not seem to be an ideal situation for using spatulas, even if an anterior rotation is achieved in one-third of cases