Comparison of Postnatal Growth Charts of Singleton Preterm and Term Infants Using World Health Organization Standards at 40-160 Weeks Postmenstrual Age: A Chinese Single-Center Retrospective Cohort Study

The growth diversity of preterm infants at 0-36 months corrected age in China: a real-world observational study

Background

Premature delivery interrupts the natural growth of the fetus. The postnatal healthy management of preterm infants still follows term standards after a postmenstrual age (PMA) of 40 weeks and there is a lack of research on the longitudinal dynamic postnatal growth tracks of preterm infants.

Methods

Based on the database established by the Wuhan University Internet+ Early Childhood Development Alliance in China, information on preterm infants, including birth registration and health follow-ups from 2016 to 2022, was incorporated into the health management system. Standardized anthropometric measurements of preterm infants were recorded from birth to a corrected age (CA) of 36 months. A generalized additive model based on location, scale, and shape was used to establish the percentile values and growth curves.

Results

In total, 79,514 preterm infants were included in this study, and the birth weights at each gestational age (GA) were similar to Chinese standards. When evaluated by term birth weight, we found that the proportions of extrauterine growth retardation at a PMA of 40 weeks were all above 10% in the GA ≤34-week groups and reached between 17.19% and 55.56% in very preterm infants (VPIs). There was a high incidence of preterm infants with a weight below the third percentile in VPIs when referring to term standards at CAs of 0, 6, 12, 24, and 36 months (p < 0.001). We established natural growth curves of the preterm population with different GAs between CAs of 0 and 36 months, which indicated that the weight/length of late preterm infants was close to term standards while the growth trajectory of VPIs consistently lagged behind (p < 0.001).

Conclusion

Our study revealed the different growth trajectories of preterm infants with different GAs. A set of growth curves and percentile values for preterm infants of different GAs between CAs of 0 and 36 months were established, offering an optional method for growth assessment of this special population.

The trajectories of physical growth in 4 months postnatal corrected age among preterm infants discharged from neonatal intensive care units and associated factors: A prospective study

Objectives

Growth retardation is a risk for premature infants. In addition to demographic and perinatal factors, preterm infants' physical growth may be affected by neonatal intensive care unit (NICU) stress, maternal postpartum depression, and mother-infant interaction. This study aimed to investigate the trajectories of physical growth in 4 months corrected age among preterm infants discharged from the NICU and the impactors on these trajectories.

Methods

A prospective study was conducted among 318 preterm infants from September 2019 to April 2021 in Shanghai, China. Latent growth modeling was applied to identify the weight, length, and head circumference growth trajectories in 4 months corrected age and explore the effects of demographic and medical characteristics, infant stress during NICU stay, maternal postpartum depression, and mother-infant interaction on each trajectory.

Results

Unconditional latent growth models showed curve trajectories with increasingly slower growth in weight, length, and head circumference until 4 months of corrected age. Conditional latent growth models showed that a longer length of stay in the NICU and more skin punctures were negatively associated with weight at 40 weeks corrected gestational age (β = -0.43 and -0.19, respectively, P < 0.05). The maternal postpartum depression between 40 weeks corrected gestational age and 1 month corrected postnatal age was associated with a lower growth rate of length (β = -0.17, P = 0.040), while between 2 and 3 months corrected postnatal age, there were lower growth rates of weight and head circumference (β = -0.15 and -0.19, respectively, P < 0.05). The mother-infant interaction scores between 40 weeks corrected gestational age and 1 month corrected postnatal age negatively predicted the growth rate of weight (β = -0.19, P = 0.020).

Conclusion

The physical growth trajectories of preterm infants discharged from the NICU were influenced by infant stress during the NICU stay, maternal postpartum depression and mother-infant interaction.

Birth weight for gestational age: standard growth charts for the Polish population

Introduction. Birth weight is one of the most important factors determining neonatal well-being. From an epidemiological viewpoint, a neonatal reference chart provides a picture of the health status of a population. Global customized growth charts seem to be the most practical in multicultural settings, allowing adjustment for ethnicity. However, regional charts might be a valuable contribution to reliable growth assessment. Our study aims to establish a reference tool for growth assessment and visualize the local potential, by creating standard charts based on the data from the tertiary center with the highest number of deliveries per year in Poland. Material and Methods. We retrospectively analysed  31,353 records from the electronic database of singleton births from a five-year period from a tertiary hospital in Poznań, Poland. We excluded pre-term deliveries and high-risk pregnancies basing on well-known factors influencing fetal growth, bringing the number of records to  21,379. The data were processed separately by gender (females n=10,312, 48.2% and males n=11,067, 51.8%). Percentiles were calculated for each week of gestational age. Means and standard deviations were determined. Results. Standard growth charts (including 3rd, 10th, 25th, 50th, 75th, 90th and 97th percentiles) are presented. Descriptive data of population distribution are shown. Conclusions. In conclusion, obtaining standard growth charts for mature newborns has created the opportunity for a more actual and adequate assessment of the Polish neonatal population. It should allow for the implementation of new standards in future research on perinatal care.

The growth rates and influencing factors of preterm and full-term infants: A birth cohort study

This study aimed to explore the growth rates and influencing factors of the length and weight of preterm and full-term infants in the urban areas of Hubei province to provide a reference for child health and related clinical fields. A birth cohort study was used to analyze the growth rates and influencing factors of the length and weight of preterm and full-term infants using a multivariate regression analysis. The growth rates of the length and weight of preterm infants were significantly lower than those of full-term infants from birth to 3 months of age (P < .05), and gradually caught up to the level of full-term infants after 3 months of age (P > .05). Meanwhile, there were some influencing factors that had significant differences by their contribution to the growth rates of the length and weight of preterm and full-term infants. This study proposed that perinatal factors were attached more importance to the growth rates of preterm infants in the urban areas of Hubei province.

Differences in Postnatal Growth of Preterm Infants in Northern China Compared to the INTERGROWTH-21st Preterm Postnatal Growth Standards: A Retrospective Cohort Study

BACKGROUND

The INTERGROWTH-21st preterm postnatal growth standards (IPPGS) have increasingly been used to evaluate the growth of preterm infants worldwide. However, the validity of IPPGS's application to specific preterm populations remains controversial. This retrospective cohort study aimed to formulate reference growth charts for a preterm cohort in northern China and compare them to the IPPGS.

METHODS

A total of 1,827 healthy preterm infants with follow-up visits before 70 weeks of postmenstrual age (PMA) were retrospectively sampled from a preterm cohort (N = 2,011) born between 1 January 2011 and 28 February 2021, at the First Affiliated Hospital of Shandong First Medical University. Using the Generalized Additive Models for Location, Scale, and Shape method, 5,539 sets of longitudinal data were used to construct percentile and Z-score charts of length, weight, and head circumference (HC) at 40-64 weeks of PMA. Z-scores of length, weight, and HC (LAZ, WAZ, and HCZ) before 64 weeks were calculated using the IPPGS. Differences in the 50th percentile values between preterm infants and IPPGS (dLength, dWeight, and dHC) were calculated. Z-scores were assigned to six PMA clusters: 40-44, 44-48, 48-52, 52-56, 56-60, and 60-64 weeks for comparison between sexes.

RESULTS

For eligible infants, the mean PMA and weight at birth were 33.93 weeks and 2.3 kg, respectively. Boys, late preterm infants, twins, and infants with exclusively breastfeeding accounted for 55.8, 70.6, 27.8, and 45.9%, respectively. Compared to IPPGS, preterm infants were longer and heavier, especially for dLength in girls (range, 2.19-2.97 cm), which almost spanned the 50th and 90th percentiles of IPPGS. The dHC tended to narrow with PMA for both sexes. The mean LAZ, WAZ, and HCZ of both sexes at all PMA clusters were >0, especially for LAZ and WAZ (about 1.0 relative to IPPGS), indicating higher levels than the IPPGS at 40-64 weeks. Girls had larger LAZ at each PMA cluster, larger WAZ at 40-44 weeks, and lower HCZ after 56 weeks than boys. HCZ declined with PMA for both sexes.

CONCLUSION

Postnatal growth of this preterm cohort was considerably higher than that of the IPPGS at 40-64 weeks of PMA with sex differences.