Postnatal growth in infants born before 30 weeks' gestation

Area of Science:

• Neonatalogy
• Pediatric Nutrition
• Growth and Development

Background:

• Premature infants born between 23 to 29 weeks' gestation require specialized nutritional support.
• Parenteral nutrition is often used to establish feeding before milk intake begins in these vulnerable infants.

Purpose of the Study:

• To determine the postnatal weight patterns of very premature infants up to 14 weeks after birth.
• To compare weight loss, regain time, and growth rates in relation to gestational age and birth weight status.

Main Methods:

• Retrospective analysis of 184 singleton survivors born between 23 to 29 weeks' gestation.
• Monitoring of postnatal weight, nutritional intake (parenteral and milk feeding), and growth parameters up to 14 weeks.
• Comparison of infants based on gestational age subgroups and small for gestational age (SGA) status.

Main Results:

• A mean postnatal weight loss of 14% of birth weight occurred around 6 days of age.
• More immature infants exhibited greater weight loss and longer recovery times, despite higher initial fluid intake.
• Postnatal weight gain exceeded intrauterine growth rates from the fourth week onwards for all gestational subgroups.
• Despite catch-up growth, mean body weight remained below the 10th percentile of the intrauterine growth curve.
• Infants small for gestational age showed higher early growth rates but remained significantly lighter at 2 years.

Conclusions:

• Very premature infants undergo significant initial postnatal weight loss, with recovery taking longer in more immature infants.
• While postnatal growth rates can surpass intrauterine rates, initial weight loss impacts long-term weight trajectory.
• Infants small for gestational age demonstrate catch-up growth but maintain lower body weight at 2 years, highlighting the need for continued monitoring.