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Published on: June 29, 2013
Comparison of fetal and neonatal growth curves in detecting growth restriction
Anna Maria Marconi1, Stefania Ronzoni, Patrizia Bozzetti
1From the Departments of Obstetrics and Gynecology and Statistics, DMSD San Paolo, University of Milan, Milan, Italy; and Division of Perinatal Medicine, Department of Pediatrics, University of Colorado School of Medicine, Denver, Colorado.
Insights
Neonatal standards for classifying intrauterine growth restriction (IUGR) infants are misleading. Neonatal outcome is similar for IUGR infants regardless of whether they are defined as appropriate for gestational age (AGA) or small for gestational age (SGA).
Area of Science:
- Perinatology
- Neonatalogy
- Fetal Medicine
Background:
- Intrauterine growth restriction (IUGR) affects fetal development.
- Umbilical artery pulsatility index is a key indicator of fetal well-being.
- Accurate classification of IUGR is crucial for predicting neonatal outcomes.
Purpose of the Study:
- To evaluate the neonatal outcomes of infants with intrauterine growth restriction (IUGR) and abnormal umbilical artery pulsatility index.
- To compare outcomes based on neonatal birth weight/gestational age standards versus intrauterine growth charts.
Main Methods:
- Analysis of 53 pregnancies with severe IUGR (abnormal pulsatility index) and 79 matched controls (normal growth).
- Comparison of neonatal birth weight, body size, maternal, obstetric, and neonatal morbidity/mortality data.
- Statistical analysis using chi-squared, Student t-tests, and analysis of covariance.
Main Results:
- 47% of IUGR infants were classified as appropriate for gestational age (AGA) and 53% as small for gestational age (SGA) by neonatal standards.
- IUGR infants (both AGA and SGA classifications) had significantly smaller body size measurements than controls.
- Higher neonatal intensive care unit admission (92% vs. 62%) and mortality (11% vs. 1%) in IUGR infants compared to AGA controls.
Conclusions:
- Neonatal outcome is similar in IUGR infants of the same clinical severity, irrespective of AGA or SGA classification by neonatal standards.
- Neonatal birth weight/gestational age curves can be misleading for identifying low birth weight infants.
- Obstetric data should be prioritized when available for accurate IUGR assessment.
Objective:
To evaluate the outcome of intrauterine growth restriction (IUGR) infants with abnormal pulsatility index of the umbilical artery according to the neonatal birth weight/gestational age standards and the intrauterine growth charts.
Methods:
We analyzed 53 pregnancies with severe IUGR classified as group 2 (22 IUGR: abnormal pulsatility index and normal fetal heart rate) and group 3 (31 IUGR: abnormal pulsatility index and fetal heart rate). Neonatal birth weight/gestational age distribution, body size measurements, maternal characteristics and obstetric outcome, and neonatal major and minor morbidity and mortality were compared with those obtained in 79 singleton pregnancies with normal fetal growth and pulsatility index, matched for gestational age (appropriate for gestational age [AGA] group). Differences were analyzed with the chi(2) test and the Student t test. Differences between means corrected for gestational age in the different groups were assessed by analysis of covariance test. A P<.05 was considered significant.
Results:
At delivery, using the neonatal standards, 25 of 53 (47%) IUGR showed a birth weight above the 10th percentile (IUGR(AGA)), whereas in 28, birth weight was below the 10th percentile (IUGR small for gestational age [SGA]-IUGR(SGA)). All body size measurements were significantly higher in AGA than in IUGR(AGA) and IUGR(SGA). Forty-nine of 79 (62%) AGA and 49 of 53 (92%) IUGR were admitted to the neonatal intensive care unit (P<.001). One of 79 (1%) AGA and 6 of 53 (11%) IUGR newborns died within 28 days (P<.02). Major and minor morbidity was not different.
Conclusion:
This study shows that neonatal outcome is similar in IUGR of the same clinical severity, whether or not they could be defined AGA or SGA according to the neonatal standards. Neonatal curves are misleading in detecting low birth weight infants and should be used only when obstetric data are unavailable.
Level Of Evidence:
II.
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