Our Maternal-Fetal Medicine fellow was talking about a delivery that occurred while I was away. The fetus was growth-restricted and developed worsening indices on Doppler ultrasound of the umbilical arteries. What was initially an increased Systolic/Diastolic ratio became first absent and then reversed end-diastolic flow. As this occurred over several weeks, the patient herself had worsening blood pressures and symptoms related to her pre-eclampsia and the fetal tracing became more concerning. She was ultimately delivered and her tiny and premature baby was now in the care of the neonatologists.
The fellow’s presentation focused on the ultrasound findings and the surveillance of pregnancies that become complicated in this way. What was known was the best current management in this case. The unknown was why this had happened in the first place. I was about to interrupt the presentation when our fellow, knowing what I was going to ask, looked over at me and said “Yes, I did collect the placenta.”
Pre-eclampsia is a common condition and growth restriction, by definition, occurs in 10% of pregnancies. The conditions are highly related. We have risk factors for both, but we seldom know the cause. Our treatments seem crude to a bench researcher; try to control the condition as long as you can, and if either patient or her fetus becomes too sick, deliver the pregnancy.
As an obstetrics and gynecology resident, I was fascinated by developmental programming in these fetuses and sent in a grant application to the American Institute of Ultrasound in Medicine requesting seed funding to look at the hormonal associations with growth restriction. Their contribution to my research was a turning point for me. I had always thought of myself as a clinical researcher and this was my first exploration of translational research. During my fellowship in Maternal-Fetal Medicine, I collected ultrasound data on growth restricted pregnancies and sampled placentas and cord blood from the pregnancies when they delivered. What I had thought would be a one-off project became a jumping off point for continued exploration into placental biology.
Five years later, I have established a placenta bank at the University of Arizona. What was a small study focusing on just one condition has inspired the creation of a bigger project. Our residents and fellows now contribute to the bank and have the ability to answer their own questions with the samples already collected. The bank is a resource to all of us and has fostered collaborations with the University of Arizona Biorepository and the department of Animal and Comparative Biomedical Sciences. My initial work focused on changes in leptin, renin, and C-reactive protein in cord blood, but as I learned more, the objective changed to include RNA analysis of the placental tissue. We noted that the structural protein expression was different in the growth-restricted pregnancies. This has led to the proposal of a whole different model regarding the causation of preeclampsia and growth restriction.
We will wait and see how this baby does in the neonatal intensive care unit. As we go about our conservative management until the risk becomes too great to continue, it is a comfort to know we are looking for reasons; if we understand possible mechanisms better, there is the potential to mitigate or reverse the development of fetal and maternal morbidities.
How has ultrasound shaped your career? Has an ultrasound study led you down an unexpected path? Comment below or let us know on Twitter: @AIUM_Ultrasound.
Meghan Hill, MBBS, is Assistant Professor at The University of Arizona College of Medicine, Department of Obstetrics & Gynecology.