NCT02713568

Estimation of Fetal Weight by MR Imaging to PREdict Neonatal MACROsomia (PREMACRO Study)

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 2,413 (actual)
• Sponsor: Brugmann University Hospital · Academic / Other
• Sex: Female
• Age: 18 Years
• Healthy volunteers: Accepted

Summary

Macrosomia and growth restriction are important causes of perinatal morbidity, at or near to term. However, clear identification of 'at risk' foetuses is difficult and clinical estimates of fetal weight are poor. Historically, ultrasound has been used as a second line in such cases but the accuracy of this imaging modality in the mid- to late third trimester is also limited. Estimated fetal weight (EFW) is an important part of the clinical assessment and is used to guide obstetric interventions, when a fetus is small or large for dates. It frequently is the single most important component guiding interventions, such as induction of labour or Caesarean section. Due to the imprecision of ultrasound-derived EFW, particularly in cases of suspected macrosomia in the 3rd trimester, the investigators believe that these estimates should not be used to make important obstetric decisions regarding mode and timing of delivery and that a more accurate method of assessment could produce better outcomes by restricting interventions to those foetuses at greatest risk. Some publications have already demonstrated that magnetic resonance (MR) imaging derived-EFW close to delivery, is more accurate than ultrasound The goal of the present study is thus to compare the performance of magentic resonance imaging derived-EFW, versus ultrasound derived-EFW at 36 weeks of gestation, regarding the prediction of neonatal macrosomia.

Detailed description

Macrosomia and growth restriction are important causes of perinatal morbidity, at or near to term. However, clear identification of 'at risk' foetuses is difficult and clinical estimates of fetal weight are poor. Historically, ultrasound has been used as a second line in such cases but the accuracy of this imaging modality in the mid- to late third trimester is also limited. Estimated fetal weight (EFW) is an important part of the clinical assessment and is used to guide obstetric interventions, when a fetus is small or large for dates. When a diagnosis of intra-uterine growth restriction (IUGR) is made, the decision-making process is complex, particularly at very early gestations and involves multiple different factors, including maternal status, cardiotocography, liquor volume and dopplers. However, a large body of research is now available to assist with the management of both early and late-onset intrauterine growth restriction (IUGR) but there is a paucity of evidence to guide clinical practice, once macrosomia has been diagnosed, therefore the EFW is frequently the single most important component guiding interventions, such as induction of labour or Caesarean section. Fetal macrosomia is associated with a higher incidence of perinatal morbidity, including shoulder dystocia and brachial plexus injury in the fetus and anal sphincter tears, uterine atony and haemorrhage in the mother. A recent multicentre randomised controlled trial appears to confirm the advantages of a policy of induction of labour for suspected macrosomia, demonstrating a clear reduction in the rates of shoulder dystocia and composite perinatal morbidity. However, some earlier but lower quality, observational studies have questioned the benefit of EFW made by ultrasonography in the last trimester, for suspected macrosomia, demonstrating that this practice can increase the risk of caesarean and instrumental delivery, without reducing perinatal morbidity. Despite this conflicting data and a lack of evidence to support routine third trimester ultrasound, the absence of specific guidance, coupled with concerns regarding perinatal outcomes,mean that obstetricians will increasingly request an ultrasound at around 34-36 weeks gestation to identify foetuses above the 90th or below the 10th centiles. This practice will inevitably lead to increased and potentially harmful interventions based on relatively inaccurate data. Due to the imprecision of ultrasound-derived EFW, particularly in cases of suspected macrosomia in the 3rd trimester, the investigators believe that these estimates should not be used to make important obstetric decisions regarding mode and timing of delivery and that a more accurate method of assessment could produce better outcomes by restricting interventions to those foetuses at greatest risk. Some publications have already demonstrated that magnetic resonance (MR) imaging derived-EFW close to delivery, is more accurate than ultrasound, with a mean percentage error superior to that of ultrasound and a recent meta-analyses has confirmed this promising accuracy. The goal of the present study is thus to compare the performance of magentic resonance imaging derived-EFW, versus ultrasound derived-EFW at 36 weeks of gestation, regarding the prediction of neonatal macrosomia.

Conditions

• Fetal Macrosomia

Interventions

Type	Name	Description
OTHER	Ultrasound examination	Prenatal Ultrasound examinations will be carried out using transabdominal sonography only by experienced consultants in MFM. Ultrasound-Estimated Fetal Weight will be obtained between 36.0-36.6 weeks of gestation, according to Hadlock et al. Operators performing the Ultrasound-Estimated Fetal Weight will be blinded to the results of Magnetic Resonance-Estimated Fetal Weight. The participants, general practitioners, obstetricians and midwifes of the patients will be aware of the results of Ultrasound-Estimated Fetal Weight which will be used for clinical management. For the primary outcome measure, macrosomia during Ultrasound-Estimated Fetal Weight will be defined as ≥ P95 based on Yudkin et al. For secondary outcome measures, it will be redefined as ≥ P90 or ≥ P99 based on Yudkin.
OTHER	Magnetic resonance examination	MRI will be performed the same day as the Ultrasound examination, using a clinical 1.5T whole-body unit. Operators performing Fetal Body Volume measurements will be blinded from Ultrasound-Estimated Fetal Weight results. Magnetic Resonance-Estimated Fetal Weight will be calculated using the equation 0,12+1,031\*Fetal Body Volume = MR imaging weight (g) developed by Baker. General practitioners, obstetricians and midwifes of the patients will be blinded to the results of the Magnetic Resonance-Estimated Fetal Weight. For the primary outcome measure, macrosomia will be defined as ≥ P95 based on Yudkin et al. For secondary outcome measures, it will be defined as ≥ P90 or ≥ P99.

Timeline

• Start date: 2016-03-08
• Primary completion: 2020-03-10
• Completion: 2020-03-10
• First posted: 2016-03-18
• Last updated: 2020-08-06

Locations

1 site across 1 country: Belgium