#333 - Exploring Healthcare Utilization in Moderate to Late Preterm Infants with Dr. Ambika Bhatnagar

Hello friends 👋

In this episode of Rupa’s Fellows Friday on The Incubator Podcast, host Rupa Srirupa welcomes Dr. Ambika Bhatnagar, a third-year neonatology fellow at Yale. Dr. Bhatnagar shares her journey from medical school in India to fellowship in the U.S. and dives into her research focusing on moderate to late preterm infants—an often overlooked but significant portion of the preterm population.

She explains why this group, though not as critically ill as extremely preterm infants, still faces unique morbidities and places a substantial burden on families and the healthcare system. Her study investigates long-term healthcare utilization in these infants over their first two years of life, analyzing not just hospital readmissions but also ER visits, subspecialty consultations, and therapy appointments.

Dr. Bhatnagar discusses her findings, including the role of breastfeeding in reducing healthcare utilization and surprising trends in demographic factors. She also shares insights on mentorship during fellowship, building a research project from scratch, and her involvement with NeoQuest, an educational platform for neonatology fellows.

This conversation highlights the importance of curiosity-driven research and its potential to improve outcomes for a vulnerable but under-researched neonatal population.

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Short Bio: Dr. Ambika Bhatnagar is a third-year Neonatology fellow at Yale University. Her research focuses on healthcare utilization in moderate to late preterm infants, exploring patterns of hospital readmissions, emergency visits, and long-term follow-up needs. She is passionate about improving outcomes for this often-overlooked neonatal population and is also involved with NeoQuest, an educational platform for neonatology fellows.

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The transcript of today's episode can be found below 👇

Srirupa: Hello everyone, welcome to another episode of the Fellow Series with the Incubator Podcast. My name is Rupa, and I'm your host in this part of the Incubator Series. I’m very excited to welcome our next guest, Dr. Ambika Bhatnagar, who is currently a third-year neonatology fellow at Yale. She graduated from BJ Medical College in India, did her residency at Riley Children’s Hospital at Indiana University, and is currently at Yale.

She is very interested in simulation-based medical training research and clinical outcomes research. I’m excited to highlight the amazing research she conducted during her fellowship on identifying and modifying risk factors associated with increased healthcare utilization in a very special patient population — the moderate to late preterm infants. So, let’s get started. Welcome, Ambika. How are you doing today?

Ambika BhatnagarI: ’m doing well. I’m post-call, but I am very excited to be on the Incubator Podcast.

Srirupa: Yay, that’s amazing. I’m always surprised by how much we work on a post-call day. I feel like that’s our baseline as neonatologists — we enjoy and spend our time on our post-call days. But let’s talk about your research. I’m very excited to hear about it, especially because I’m so happy that someone is studying moderate to late preterm infants. They are such an interesting patient population, and we can talk more about that. But first, I’d love to hear about your project.

Ambika Bhatnagar: Yes, I agree. My study looks at moderate to late preterm infants, which is one of the most understudied subgroups in the preterm population. I’m interested in this population because they actually make up the majority — about 80–85% of the preterm population. They’re not as sick as our extremely preterm infants, but they are not the same as term infants either. In the last decade, more research has shown that late preterm infants differ significantly from term infants. Delivering at 35 or 36 weeks — often for maternal reasons — is not the same as having a term baby. As we study this group more, we’ve learned they have higher rates of morbidity and mortality compared to term infants. This creates a burden on families and the healthcare system. Given their large numbers, I wanted to specifically examine the healthcare utilization of these babies in their first few years of life.

Srirupa: That’s amazing. You said it so well — this is a large patient population but so understudied. I feel like if you surveyed most neonatologists, they would say this isn’t their favorite group because they’re “not supposed” to be sick, but when they do get sick, it’s serious. They don’t eat well, they get hypoglycemia, and they can look deceptively healthy, which makes it hard for parents to understand why they have breathing or feeding problems. It’s impressive that you chose this population, and I think it will inspire other neonatology fellows to explore research beyond the usual focus. Share with us about your project.

Ambika Bhatnagar: When I developed an interest in this topic, I started with a literature review. I found a lot of research on immediate readmissions in this population — what happens in the first few weeks or months after discharge — but not much on the first two years of life, which we track in other preterm groups. Another gap was in overall healthcare utilization. Most studies only looked at ER visits or readmissions, but I wanted to capture everything — specialty visits, therapy, labs, imaging — because those also create a significant burden for families.

Srirupa: That’s great. How did you plan your project, and what did you find?

Ambika Bhatnagar: It wasn’t easy, but I had a great mentor. We looked at babies born in our healthcare system — four NICUs in total, one level 4 and three level 3’s — between 32+0 and 36+6 weeks’ gestation over five and a half years (January 2016 to July 2021). We excluded babies with major congenital anomalies or complex heart disease, as those babies would have increased healthcare utilization at baseline. We also excluded those who died during birth hospitalization or didn’t follow up in our system. Our final cohort was 3,818 infants.

We extracted the data from Epic with the help of our analytics team, but cleaning the dataset was a massive task. Initially, there were about 80,000 encounters in the first two years of life, which I consolidated to about 40,000 after removing duplicates (e.g., one visit counted as multiple encounters – for example, an infant saw a cardiologist, had an echo and an EKG may have been counted as three separate encounters). I categorized encounters into ten types — hospitalizations, ER visits, specialty visits, therapy, labs, imaging, etc.

Another thing that is missing in the literature is how to describe health care utilization; there is no standardized information. There is no validated tool that describes what's high utilization and what's low utilization. So we described utilization patterns, then calculated total encounters per baby. Based on that, we divided the cohort into low, medium, and high utilizers, adjusting for follow-up time. Using a multinomial regression model, we identified maternal, neonatal, and social risk factors for high versus low utilization.

It's so interesting with large datasets how many different ways there are to interpret the results. One key finding was that breastfeeding at discharge was associated with decreased healthcare utilization — a modifiable factor. Interestingly, earlier studies found breastfeeding was linked to higher utilization in the first month due to jaundice, but our longer-term view showed the opposite. Another interesting finding was that being identified as Black/African American was associated with lower utilization, which we’re still exploring.

Srirupa: That’s fascinating and really adds to the literature on this tricky patient group. You mentioned your mentorship at Yale — tell us how you found your mentor and developed that relationship.

Ambika Bhatnagar: I’ve always been interested in clinical outcomes research. Clinically, I enjoy talking to parents and answering their questions about long-term outcomes. There’s still so much we don’t know, and the EHR contains so much valuable data if we can clean and interpret it.

At Yale, I shared my interests widely and was advised to meet many people before committing to a mentor — finding someone who matches not just your interests but also your personality and mentorship style. I was fortunate to meet Dr. Katie Buck in neonatology, who shares my passion for studying moderate to late preterm infants.

Srirupa: That’s wonderful. As you rightly said, you have to meet as many people as possible, because you never know who will turn out to be your life mentor versus career mentor versus a research project mentor. So I totally get that because I think that we tend to explore so much in fellowship. And one of the biggest things that we get as part of our fellowship is lifelong mentorship from the attendings that we work with during fellowship.

I also saw that you’re involved in NeoQuest. Tell our listeners about it.

Ambika Bhatnagar: NeoQuest is a platform by NeoReviews where we publish a question each month based on newly published articles. It’s great for fellows interested in writing and literature review. We create questions in an engaging, educational format. It’s been a great way to combine my love of teaching, literature review, and creative question writing.

Srirupa: I agree — I would also add to that that I was a junior author for two years with NeoQuest and it was a very fulfilling experience. You get to study the process of writing an article and writing a question. So it sort of like satisfies that educator in you because you're actually working on how you create a question, how that question can be tricky in a lot of ways, and how you can create explanations that would be helpful for readers. You get to work with Dr. Rita Datis and Dr. Dara Brodsky, who are master educators globally and nationally. And so that also adds to the experience as well. I got promoted as a senior author there. And so me and Ambika are working together. It's a wonderful, wonderful opportunity for Neonatology fellows interested in education. Ambika, you’ve done amazing work. What advice would you give incoming fellows interested in your research area?

Ambika Bhatnagar: Be curious — whether in clinical care or research. That curiosity will lead you to your scholarly work, whether QI or clinical outcomes research. For outcomes research, find a great mentor, network, and don’t be intimidated by large datasets — the skills can be learned. It’s incredibly satisfying to turn a messy dataset into clear, meaningful results.

Srirupa: Absolutely — every fellow knows the joy of a beautiful final table! So, what’s next for your career?

Ambika Bhatnagar: I’m currently looking for a job and want to stay in academics. I’d like to teach and continue building on the skills I’ve developed.

Srirupa: That’s wonderful. I’m sure you’ll shine wherever you go. Thank you for joining us today and sharing your work.