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Prematurity Awareness Month: Research on Moderate to Late Preterm Infants

November 19, 2024

With Dr. Catherine Buck

We spoke to Dr. Catherine Buck whose research focuses heavily on moderate to late preterm infants. Here's some of what she's been working on in honor of Prematurity Awareness Month.

What are some key discoveries you've made recently?

The goal of my research is to understand how early life factors, such as health problems during pregnancy or how a baby grew or developed during pregnancy, may influence the way a baby growth and develops after birth and through early childhood. We want to use that information to help us improve our clinical decisions early on so that we can minimize risks later. I have focused my work on moderate to late preterm infants, which have often been labeled as the ‘forgotten preemies’. These infants are born just slightly preterm, 4 to 8 weeks too early. While infants born moderate and late preterm usually do well after birth, we have learned that they are still at risk of some complications from being born preterm, such as differences in the way that they grow and differences in the way that they may learn and behave in school.

Using data from babies born at our center at Yale, as well as data from neonatal intensive care units (NICUs) in the U.S., we have found that moderate to late preterm infants whose mother had diabetes in pregnancy, had some differences in the way that they grew in the first week or so after birth. We worry that these subtle changes in early weight may have consequences long term. We published these studies in the last 2 years. These studies have led us to design an observational study of infants born moderate to late preterm in our NICU to understand WHY we see some of these early differences in weight, and to try to figure out if there are long term consequences of these early weight changes. We first designed a pilot study, in which we enrolled 150 babies born after 30 weeks gestational age and followed some measures of fat tissue development through the time of hospital discharge. We have not published our results of that pilot study yet, but our preliminary work has found some differences in fat measures at discharge in preterm babies born to a mother with diabetes in pregnancy (higher measures of fat!) compared to babies who were born at term and not exposed to diabetes in pregnancy. We have also been working explore some hormone and metabolite changes in the blood, urine, and breastmilk of these infants to try and understand if there are some early markers which can either predict these changes or help explain why. We are starting to see some differences in the patterns of metabolites and hormones related to fat tissue development in the blood and urine of babies in the diabetes exposed groups compared to those not in the diabetes group. This includes higher levels of metabolites related to protein synthesis and lipid metabolism, which are important substrates for growth and fat development.

What is the most innovative aspect of your research?

I think that the most innovative aspect of my work is first, the population that we are studying – as I mentioned this group of moderate to late preterm infants is understudied, but they make up the majority of those that we care for in the NICU. And second, our group has been working to use comprehensive body composition assessments to try to really understand what “growth” means in this group, beyond just weight and length. We use point of care ultrasound (POCUS) to try to find regions of the body where fat is developing. To that end, I was involved in a multicenter study where we were one of the first groups to describe using this methodology in preterm infants longitudinally.

Why is this research important during Prematurity Awareness Month?

We are working to try and prevent any consequences (that we can) from being born preterm. We take care of babies in the NICU during this critical window of development, and there are long term consequences of all the clinical decisions that we make.

What is your favorite aspect of your research?

The longitudinal connections that our research team is able to make with the families that are involved in our studies is really rewarding. It’s really inspiring that our patients want to be involved in our studies so that they can help figure out how to provide better care for the babies that come after them. It’s also really fun taking pictures with the ultrasound machine of babies' bicep muscles, and then showing their parents how strong their babies are getting over time.

What are some key takeaways for readers?

Moderate to late preterm infants, the ‘forgotten preemies’ are the most common infants that we care for in our NICU. We don’t have enough research specific to this group to really know how best to help this group of infants grow in the NICU and afterward. We think that growth beyond weight and length is important, but we are still trying to figure exactly what parts of that growth is the best pattern or proportion.

What comes next? More studies, clinical changes, legislation/advocacy/policy?

More research! As we continue to follow our research subject over time, we hope to be able to try to find interventions (or different ways that we provide nutrition) that we can additionally study.