Doppler ultrasound of umbilical and middle cerebral artery in third trimester small-for-gestational age fetuses to decide on timing of delivery for suspected fetal growth restriction: A cohort with nested RCT (DRIGITAT).

OBJECTIVE: To assess the association of the umbilicocerebral ratio (UCR) with adverse perinatal outcome in late preterm small-for-gestational age (SGA) fetuses and to investigate the effect on perinatal outcomes of immediate delivery. DESIGN: Multicentre cohort study with nested randomised controlled trial (RCT). SETTING: Nineteen secondary and tertiary care centres. POPULATION: Singleton SGA pregnancies (estimated fetal weight [EFW] or fetal abdominal circumference [FAC] <10th centile) from 32 to 36+6 weeks. METHODS: Women were classified: (1) RCT-eligible: abnormal UCR twice consecutive and EFW below the 3rd centile at/or below 35 weeks or below the 10th centile at 36 weeks; (2) abnormal UCR once or intermittent; (3) never abnormal UCR. Consenting RCT-eligible patients were randomised for immediate delivery from 34 weeks or expectant management until 37 weeks. MAIN OUTCOME MEASURES: A composite adverse perinatal outcome (CAPO), defined as perinatal death, birth asphyxia or major neonatal morbidity. RESULTS: The cohort consisted of 690 women. The study was halted prematurely for low RCT-inclusion rates (n = 40). In the RCT-eligible group, gestational age at delivery, birthweight and birthweight multiple of the median (MoM) (0.66, 95% confidence interval [CI] 0.59-0.72) were significantly lower and the CAPO (n = 50, 44%, p < 0.05) was more frequent. Among patients randomised for immediate delivery there was a near-significant lower birthweight (p = 0.05) and higher CAPO (p = 0.07). EFW MoM, pre-eclampsia, gestational hypertension and Doppler classification were independently associated with the CAPO (area under the curve 0.71, 95% CI 0.67-0.76). CONCLUSIONS: Perinatal risk was effectively identified by low EFW MoM and UCR. Early delivery of SGA fetuses with an abnormal UCR at 34-36 weeks should only be performed in the context of clinical trials.

Practice variation in diagnosis, monitoring and management of fetal growth restriction in the Netherlands.

OBJECTIVES: Fetal growth restriction (FGR) is a condition characterized by its complexity in diagnosis and management. There is a need for early accurate diagnosis, evidence-based monitoring and management of FGR to improve neonatal outcomes. This study evaluated differences and similarities in protocols of Dutch hospitals in the approach of (suspected) FGR in the context of the national guideline. STUDY DESIGN: FGR protocols were collected from Dutch hospitals between November 2019 and June 2020. Collected data were coded for further analysis and categorized in eight predetermined key domains of definition, preventive measures, testing, referral, monitoring strategies, interventions, mode of delivery and pathologic placenta examination. RESULTS: 55 of 71 approached hospitals (78 %) responded to the request and 54 protocols (76 %) were obtained. Protocols used variable definitions of FGR, and management was mostly based on fetal biometry results in combination with Doppler results (n = 47, 87 %). In pregnancies with an abdominal circumference (AC) or an estimated fetal weight (EFW) <10th percentile with normal Doppler results, induction of labour was recommended ≥37 weeks (n = 1, 2 %), ≥38-40 weeks (n = 23, 43 %); ≥41 weeks (n = 1, 2 %) or not specified (n = 29, 54 %). In case of an umbilical artery (UA) Doppler pulsatility index >95th percentile, (preterm) labour induction was recommended in the majority of the protocols regardless of fetal size (≥36 weeks: n = 2, 4 %; ≥37 weeks: n = 41, 76 %, not stated: n = 11, 20 %). CONCLUSION: This study found practice variation in all predetermined domains of FGR protocols of Dutch hospitals, underscoring the complexity of the condition. The differences found in this study feed the research agenda that informs the process of improving obstetric care by better identification of the fetus at risk for consequences of FGR, improving evidence-based monitoring strategies to identify (imminent) fetal hypoxia, and more accurate timing of delivery.

The Possible Role of Placental Morphometry in the Detection of Fetal Growth Restriction.

Fetal growth restriction (FGR) is often the result of placental insufficiency and is characterized by insufficient transplacental transport of nutrients and oxygen. The main underlying entities of placental insufficiency, the pathophysiologic mechanism, can broadly be divided into impairments in blood flow and exchange capacity over the syncytiovascular membranes of the fetal placenta villi. Fetal growth restriction is not synonymous with small for gestational age and techniques to distinguish between both are needed. Placental insufficiency has significant associations with adverse pregnancy outcomes (perinatal mortality and morbidity). Even in apparently healthy survivors, altered fetal programming may lead to long-term neurodevelopmental and metabolic effects. Although the concept of fetal growth restriction is well appreciated in contemporary obstetrics, the appropriate detection of FGR remains an issue in clinical practice. Several approaches have aimed to improve detection, e.g., uniform definition of FGR, use of Doppler ultrasound profiles and use of growth trajectories by ultrasound fetal biometry. However, the role of placental morphometry (placental dimensions/shape and weight) deserves further exploration. This review article covers the clinical relevance of placental morphometry during pregnancy and at birth to help recognize fetuses who are growth restricted. The assessment has wide intra- and interindividual variability with various consequences. Previous studies have shown that a small placental surface area and low placental weight are associated with a slower growth of the fetus. Parameters such as placental surface area, placental volume and placental weight in relation to birth weight can help to identify FGR. In the future, a model including sophisticated antenatal placental morphometry may prove to be a clinically useful method for screening or diagnosing growth restricted fetuses, in order to provide optimal monitoring.