Diagnostic Accuracy of Ultrasound Scanning for Prenatal Microcephaly in the context of Zika Virus Infection: A Systematic Review and Meta-analysis

Ezinne C Chibueze,Takemoto Yo,Alex J Q Parsons,Amarjargal Dagvadorj,Chie Nagata,Katharina Da Silva Lopes,Naho Morisaki,Toshiyuki Swa,Olufemi T Oladapo,Erika Ota,Nobuyuki Horita,Olukunmi O Balogun,Rintaro Mori

doi:10.1038/s41598-017-01991-y

Abstract

To assess the accuracy of ultrasound measurements of fetal biometric parameters for prenatal diagnosis of microcephaly in the context of Zika virus (ZIKV) infection, we searched bibliographic databases for studies published until March 3rd, 2016. We extracted the numbers of true positives, false positives, true negatives, and false negatives and performed a meta-analysis to estimate group sensitivity and specificity. Predictive values for ZIKV-infected pregnancies were extrapolated from those obtained for pregnancies unrelated to ZIKV. Of 111 eligible full texts, nine studies met our inclusion criteria. Pooled estimates from two studies showed that at 3, 4 and 5 standard deviations (SDs) <mean, sensitivities were 84%, 68% and 58% for head circumference (HC); 76%, 58% and 58% for occipitofrontal diameter (OFD); and 94%, 85% and 59% for biparietal diameter (BPD). Specificities at 3, 4 and 5 SDs below the mean were 70%, 91% and 97% for HC; 84%, 97% and 97% for OFD; and 16%, 46% and 80% for BPD. No study including ZIKV-infected pregnant women was identified. OFD and HC were more consistent in specificity and sensitivity at lower thresholds compared to higher thresholds. Therefore, prenatal ultrasound appears more accurate in detecting the absence of microcephaly than its presence.

Highlights

Is a sign of fetal brain abnormality in which there is a significantly small head size for gestational age and sex
The World Health Organization (WHO) interim guidance recommends that pregnant women residing in areas of ongoing Zika virus (ZIKV) transmission should have fetal ultrasound scans to exclude microcephaly or other brain abnormalities that have been reported in fetuses of women with prenatal ZIKV infection[4]
Prenatal assessment of microcephaly has conventionally relied on ultrasound measurements of fetal biometric parameters such as the head circumference, biparietal diameter and occipitofrontal diameter[5,6,7]

Summary

Introduction

Is a sign of fetal brain abnormality in which there is a significantly small head size for gestational age and sex. Infants born with microcephaly are likely to present with variable clinical features ranging from subtle impairment in neurological development to serious intellectual disabilities in the long term. It is a rare condition occurring in 5.8 to 18.7 per 100,000 pregnancies and often arising from a wide variety of conditions that can cause abnormal brain growth[1]. In 2015, a 20-fold increase in neonatal microcephaly was observed in association with Zika virus (ZIKV) infections in pregnant women in Latin America[2]. Prenatal assessment of microcephaly has conventionally relied on ultrasound measurements of fetal biometric parameters such as the head circumference, biparietal diameter and occipitofrontal diameter[5,6,7]. Due to the rare nature of this condition, the application of different parameters and limits, the risk of wrong or missed diagnosis is high[9,10,11,12]

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Results

Conclusion