Exploring prenatal stress and its influence on maternal placental physiology and infant development in Galapagos

Recent UNC PhD graduate Dr. Hannah Jahnke and team including UNC’s Dr. Amanda Thompson and USFQ’s Dr. Enrique Teran have published a paper in Placenta titled “Maternal stress, placental 11β-hydroxysteroid dehydrogenase type 2, and infant HPA axis development in humans: Psychosocial and physiological pathways.” This was a collaborative effort with Oskar Jandl Hospital on San Cristobal, Galapagos.

This paper looked at 24 mothers and infants in Galapagos and highlights how prenatal stress influences maternal placental physiology and infant development. They find that high maternal stress decreases the expression of a protective enzyme and thus increases an infant’s long-term disease risk.

Maternal prenatal stress has been shown to disregulate an infant’s hypothalamic-pituitary-adrenal axis (HPA axis) development, leading to a higher risk for metabolic and neurobehavioral disorders in the long-term. During pregnancy, placental 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2) protects the fetus from high levels of maternal cortisol (commonly known as the “stress hormone”) by limiting the amount of cortisol that reaches the fetus, but little is known about what influences its functioning.

In this work, researchers assessed how maternal distress influences placental HSD11B2 functioning (through both methylation and expression), and how HSD11B2 in turn, is associated with infant HPA axis development. It was concluded that maternal HPA axis disregulation (based on cortisol) during pregnancy is associated with lower placental HSD11B2 expression, which is associated with an exaggerated cortisol reactivity in infants. While these results are seemingly contradictory to an adaptive framework, where maternal distress would decrease HSD11B2 methylation, thus increasing HSD11B2 expression to provide a protective effect to the infant in times of adversity, these results are consistent with findings from many other studies and may fit into a broader physiological model where adaptive responses become disrupted through overuse.

Further, sex-specific analyses revealed that maternal depressive symptoms may influence the functioning of placental HSD11B2 differently in girls (n = 11, 46%) than in boys (n = 13, 54%), though the sample size was small. Specifically, maternal depressive symptoms were marginally associated with higher HSD11B2 methylation and significantly associated with lower HSD11B2 expression in the placentas of girls, but not of boys. These results are consistent with others’ findings that infant sex is often associated with differences in placental function and physiology.

Although the mechanisms behind sex differences in fetal programming remain unknown, others have suggested that these differences in early life may be the consequence of a “viability-vulnerability tradeoff,” in which males do not adjust to early life adversity, and thus only the most fit survive, while females modify their growth in response to adversity, improving their viability but increasing their vulnerability to the deleterious effects of these adjustments later in life.

This work contributes to evolutionary theories of early life adaptation and serves as foundational exploratory research on the understudied placental influence on fetal programming, which has consequences for long-term disease development. To our knowledge, this is one of the first studies to examine how both HSD11B2 methylation and expression in the placenta respond to maternal distress and shape infant cortisol

Recent Posts


Follow Us

Scroll to Top

In 2022, the Galapagos Science Center (GSC) and the broader UNC & USFQ Galapagos Initiative will celebrate its 10th Anniversary. We are proud to announce the World Summit on Island Sustainability scheduled to be held on June 26–30, 2022 at the Galapagos Science Center and the Community Convention Center on San Cristobal Island.

The content of the World Summit will be distributed globally through social media and results documented through papers published in a book written as part of the Galapagos Book Series by Springer Nature and edited by Steve Walsh (UNC) & Carlos Mena (USFQ) as well as Jill Stewart (UNC) and Juan Pablo Muñoz (GSC/USC). The book will be inclusive and accessible by the broader island community including scientists, managers, residents, tourists, and government and non-government organizations.

While the most obvious goal of organizing the World Summit on Island Sustainability is to celebrate the 10th Anniversary of the GSC and the UNC-USFQ Galapagos Initiative, other goals will be addressed through special opportunities created as part of our operational planning of the World Summit.

For instance, we seek to elevate and highlight the Galapagos in the island conservation discourse, seeking to interact with other island networks in more obvious and conspicuous ways to benefit the Galapagos Islands, the UNC-USFQ Galapagos Initiative, and the world. We will seize the opportunity to further develop the I2N2 – International Islands Network-of-Networks. Further, we wish to highlight and emphasize multiple visions of a sustainable future for the Galapagos Islands and we cannot do this alone. Therefore, engaging the Ecuadorian Ministry of Environment, the Ministry of Tourism, the Government Council of Galapagos, the Galapagos National Park, and local Galapagos authorities, including government and non-government organizations and local citizen groups, is imperative.

The Galapagos Science Center on San Cristobal Island, Galapagos

Borrowing from Hawaii’s and Guam’s Green Growth Program and the Global Island Partnership, we wish to examine existing global programs that emphasize island sustainability and their incorporation into life, policies, and circumstances in the Galapagos Islands. We will also seek to enhance our connections with the institutional members of our International Galapagos Science Consortium and expand the Consortium through the recruitment of other member institutions. We will also work to benefit islands and their local communities by working with citizen groups as well as important NGOs who seek to improve the natural conditions in the Galapagos and diminish the impact of the human dimension on the future of Galapagos’ ecosystems.

Lastly, we will use the World Summit to benefit UNC & USFQ and our constituencies through a strong and vibrant communication plan about the World Summit, creating corporate relationships as sponsors, identifying funding goals through donors, and benefiting our study abroad program for student engagement in the Galapagos Islands. We plan to develop and issue a Galapagos Sustainability Communique after the World Summit that includes the vision and insights of all its participants for a sustainable Galapagos with applicability to global island settings.

We are eager to hear your perspective and have you join us at the World Summit on Island Sustainability!