Early biometric lag in the prediction of small for gestational age neonates and preeclampsia

Prediction of neonatal outcomes using gestational age vs ACOG definitions of maternal disease severity in hypertensive disorders of pregnancy

PURPOSE

Hypertensive disorders of pregnancy cause significant neonatal complications. Disease severity is often used to predict neonatal outcomes, however gestational age (GA) at delivery may be a better predictor. We aimed to assess whether disease severity or GA was more predictive of adverse neonatal outcomes.

METHODS

We included 165 participants with confirmed HELLP syndrome or severe preeclampsia (sPE). Two predictive models were constructed to assess the ability of disease severity compared to GA to predict a composite adverse neonatal outcome. The composite outcome included low birth weight, SGA, IUGR, Apgar score, and neonatal death.

RESULTS

Using severity as a predictor of binary neonatal outcome had an AUC of 0.73 (0.65-0.81), with a sensitivity (SE) of 70.3% and a specificity (SP) of 64.4%. For GA, we observed an AUC of 0.82 (0.75-0.89), with a SE of 75.7% and a SP of 76.7%.

CONCLUSION

For the composite neonatal outcome, GA was a better predictor than ACOG diagnosis (severity). This observation underscores the need for further research to validate these findings in larger cohorts and to determine their applicability to maternal outcomes.

Reduced fetal growth velocity and weight loss are associated with adverse perinatal outcome in fetuses at risk of growth restriction

BACKGROUND

Although fetal size is associated with adverse perinatal outcome, the relationship between fetal growth velocity and adverse perinatal outcome is unclear.

OBJECTIVE

This study aimed to evaluate the relationship between fetal growth velocity and signs of cerebral blood flow redistribution, and their association with birthweight and adverse perinatal outcome.

STUDY DESIGN

This study was a secondary analysis of the TRUFFLE-2 multicenter observational prospective feasibility study of fetuses at risk of fetal growth restriction between 32⁺⁰ and 36⁺⁶ weeks of gestation (n=856), evaluated by ultrasound biometry and umbilical and middle cerebral artery Doppler. Individual fetal growth velocity was calculated from the difference of birthweight and estimated fetal weight at 3, 2, and 1 week before delivery, and by linear regression of all available estimated fetal weight measurements. Fetal estimated weight and birthweight were expressed as absolute value and as multiple of the median for statistical calculation. The coefficients of the individual linear regression of estimated fetal weight measurements (growth velocity; g/wk) were plotted against the last umbilical-cerebral ratio with subclassification for perinatal outcome. The association of these measurements with adverse perinatal outcome was assessed. The adverse perinatal outcome was a composite of abnormal condition at birth or major neonatal morbidity.

RESULTS

Adverse perinatal outcome was more frequent among fetuses whose antenatal growth was <100 g/wk, irrespective of signs of cerebral blood flow redistribution. Infants with birthweight <0.65 multiple of the median were enrolled earlier, had the lowest fetal growth velocity, higher umbilical-cerebral ratio, and were more likely to have adverse perinatal outcome. A decreasing fetal growth velocity was observed in 163 (19%) women in whom the estimated fetal weight multiple of the median regression coefficient was <-0.025, and who had higher umbilical-cerebral ratio values and more frequent adverse perinatal outcome; 67 (41%; 8% of total group) of these women had negative growth velocity. Estimated fetal weight and umbilical-cerebral ratio at admission and fetal growth velocity combined by logistic regression had a higher association with adverse perinatal outcome than any of those parameters separately (relative risk, 3.3; 95% confidence interval, 2.3-4.8).

CONCLUSION

In fetuses at risk of late preterm fetal growth restriction, reduced growth velocity is associated with an increased risk of adverse perinatal outcome, irrespective of signs of cerebral blood flow redistribution. Some fetuses showed negative growth velocity, suggesting catabolic metabolism.

External validation and clinical usefulness of first-trimester prediction models for small- and large-for-gestational-age infants: a prospective cohort study

Objective

To assess the external validity of all published first‐trimester prediction models based on routinely collected maternal predictors for the risk of small‐ and large‐for‐gestational‐age (SGA and LGA) infants. Furthermore, the clinical potential of the best‐performing models was evaluated.

Design

Multicentre prospective cohort.

Setting

Thirty‐six midwifery practices and six hospitals (in the Netherlands).

Population

Pregnant women were recruited at <16 weeks of gestation between 1 July 2013 and 31 December 2015.

Methods

Prediction models were systematically selected from the literature. Information on predictors was obtained by a web‐based questionnaire. Birthweight centiles were corrected for gestational age, parity, fetal sex, and ethnicity.

Main outcome measures

Predictive performance was assessed by means of discrimination (C‐statistic) and calibration.

Results

The validation cohort consisted of 2582 pregnant women. The outcomes of SGA <10th percentile and LGA >90th percentile occurred in 203 and 224 women, respectively. The C‐statistics of the included models ranged from 0.52 to 0.64 for SGA (n = 6), and from 0.60 to 0.69 for LGA (n = 6). All models yielded higher C‐statistics for more severe cases of SGA (<5th percentile) and LGA (>95th percentile). Initial calibration showed poor‐to‐moderate agreement between the predicted probabilities and the observed outcomes, but this improved substantially after recalibration.

Conclusion

The clinical relevance of the models is limited because of their moderate predictive performance, and because the definitions of SGA and LGA do not exclude constitutionally small or large infants. As most clinically relevant fetal growth deviations are related to ‘vascular’ or ‘metabolic’ factors, models predicting hypertensive disorders and gestational diabetes are likely to be more specific.

Tweetable abstract

The clinical relevance of prediction models for the risk of small‐ and large‐for‐gestational‐age is limited.

The clinical relevance of prediction models for the risk of small‐ and large‐for‐gestational‐age is limited.

Slow fetal growth between first and early second trimester ultrasound scans and risk of small for gestational age (SGA) birth

Objectives

To investigate the association between fetal growth between first and early second trimester ultrasound scan and the risk of severe small for gestational age (SGA) birth.

Methods

This cohort study included 69 550 singleton pregnancies with first trimester dating and an early second trimester growth scan in Stockholm and Gotland Counties, Sweden between 2008 and 2014. Exposure was difference in biparietal diameter growth between observed and expected at the second trimester scan, calculated by z-scores. Risk of birth of a severe SGA infant (birth weight for gestational age by fetal sex less than the 3^rd centile) was calculated using multivariable logistic regression analysis and presented as adjusted odds ratio (aOR).

Results

Parietal growth less than 2.5 percentile between first and second trimester ultrasound examination was associated with elevated risk of being born severe SGA. (aOR 1.67; 95% Confidence Interval 1.28–2.18). The risks of preterm severe SGA (birth before 37 weeks) and term severe SGA (birth 37 weeks or later) were at similar levels, and risk of severe SGA were also elevated in the absence of preeclampsia, hypertensive diseases or gestational diabetes.

Conclusions

Fetuses with slow growth of biparietal diameter at ultrasound examination in early second trimester exhibit increased risk of being born SGA independent of gestational age at birth and presence of maternal hypertensive diseases or diabetes mellitus.

Two-dimensional sonographic placental measurements in the prediction of small-for-gestational-age infants

OBJECTIVES

To determine the utility of two-dimensional (2D) sonographic placental measurements in the prediction of small-for-gestational-age (SGA) infants.

METHODS

The maximal diameter along the fetal surface of the placenta and the maximal placental thickness were measured at 18-24 weeks' gestation, and the measurements repeated in the orthogonal plane. 'Biometric lags' were calculated as the difference between sonographic gestational age, estimated using each of a number of fetal biometric measurements, and actual gestational age. These variables were analyzed individually and in combination as predictors of birth weight<10(th) percentile (SGA<10) and <5(th) percentile (SGA<5).

RESULTS

1909 singleton pregnancies were included. Mean placental diameter (SGA<10, P<0.001; SGA<5, P=0.002) and thickness (SGA<10, P<0.006; SGA<5, P=0.065) were significantly smaller in SGA pregnancies. The biometric lags were greater in SGA pregnancies, the lag in abdominal circumference (AC) being the most predictive of SGA (P<0.0001). Multivariable models were significantly predictive of both SGA<10(th) percentile (area under the receiver-operating characteristics curve (AUC) =0.7404) and <5(th) percentile (AUC=0.7204), the best fitting models including AC lag and mean placental diameter and thickness.

CONCLUSIONS

2D placental measurements taken in mid-gestation are significantly associated with the incidence of SGA. Biometric lags can improve the predictive ability further. These easily obtained variables should be considered in future efforts to develop a clinically useful predictive model for adverse outcome of pregnancy.

Ultrasound assessment of intrauterine growth restriction: relationship to neonatal body composition

OBJECTIVE

The objective of the study was to compare prenatal ultrasound parameters for intrauterine growth restriction (IUGR) with newborn percent body fat (%BF).

STUDY DESIGN

This was a prospective study of 87 pregnancies followed with ultrasound. Subjects were categorized into 3 groups: estimated fetal weight (EFW) less than the 10th percentile, abdominal circumference (AC) less than the fifth percentile, and normal biometry. Neonatal %BF by air displacement plethysmography was compared between each group using multivariable analyses.

RESULTS

The %BF in the EFW less than the 10th percentile group (5.1 ± 2.9%) was significantly lower than either AC less than the fifth percentile (9.5 ± 3.3%) or normal groups (11.6 ± 5.6%). EFW less than the 10th percentile best predicted %BF by regression model. Neonatal morbidity was not significantly higher in the EFW less than the 10th percentile group.

CONCLUSION

Newborn %BF was significantly lower in infants with EFW less than the 10th percentile compared with AC less than the fifth percentile, an intermediate finding. An AC less than the fifth percentile on ultrasound does not reflect the same severity of IUGR as EFW less than the 10th percentile.