P3 Cohort Papers
Below are the papers authored by members of the P3 Cohort team (names in bold) using data from the P3 Cohort study.
2026
Salah H, Stephenson N, Skiffington J, Leijser LM, Slater D, Metcalfe A. The association between neighborhood walkability and postpartum weight retention: A prospective cohort study. Public Health. 2026;254:106228.
In this recent study, published in Public Health, members of the P3 Cohort team explore whether living in a more walkable neighbourhood influences weight retention after pregnancy.
Using P3 Cohort data, we found that about 70% of participants retained some pregnancy weight at 6-12 months postpartum.
Participants living in more walkable neighbourhoods had lower Body Mass Index (BMI) before pregnancy. However, neighbourhood walkability was not associated with postpartum weight retention.
These findings suggest that postpartum weight may be influenced by many factors beyond neighbourhood design alone, including lifestyle and individual health behaviours.
Srajer A, Harris M, Santos J, Dalere J, King JA, Skiffington JC, Slater D, Leijser L, Metcalfe A. Obstetrical outcomes in pregnant patients following a gluten-free diet: A prospective cohort study. Int J Gynaecol Obstet. 2026.
In this recent study, published in the International Journal of Gynecology & Obstetrics, Dr. Amelia Srajer and members of the P3 Cohort team explored whether following a gluten-free diet during pregnancy is linked to differences in pregnancy and birth outcomes. Gluten-free diets are becoming more common, but there is still limited research on how they may affect pregnancy.
Using data from over 2,300 participants in the P3 Cohort, the study found that about 5% followed a gluten-free diet during pregnancy. Participants who followed a gluten-free diet had similar pregnancy and birth outcomes compared to those who did not. This included outcomes such as preterm birth, gestational diabetes, and cesarean birth—and findings were similar even among participants without celiac disease.
These results suggest that, in this cohort, following a gluten-free diet during pregnancy was not linked to increased risk of adverse outcomes. More research is still needed, but this study helps provide helpful information for individuals and families making dietary choices during pregnancy.
2025
Lambert T, Stephenson N, Skiffington J, Slater D, Leijser LM, Metcalfe A. Impact of couple vs. individual participation in pregnancy research: A comparative analysis of participant characteristics and study retention. Ann Epidemiol. 2025;111:163-167.
In this recent study, published in Annals of Epidemiology, members of the P3 Cohort team explored whether having partners participate in pregnancy research affects who joins studies and how long participants stay involved. Partner participation in research is becoming more common, but its impact on study engagement is not well understood.
Using data from the P3 Cohort, the study found that participants whose partners also took part were slightly more likely to remain in the study through the first year after birth. Specifically, 98.9% of participants with partner involvement stayed in the study, compared to 97.1% of those whose partners did not participate.
These results suggest that involving partners may help improve participant retention and support longer-term engagement in pregnancy research. This can help researchers better understand family health and experiences during and after pregnancy.
Pekarsky C, Skiffington J, Chaput K, Slater D, Leijser LM, Metcalfe A. 2025. The impact of relationship factors on antenatal depression in the context of the COVID-19 pandemic. Birth. 2025;52(1):78-88.
In this recent study, published in Birth, members of the P3 Cohort team explored how relationship factors and pandemic-related stress influenced depression during pregnancy. The COVID-19 pandemic created unique challenges for many families, but its impact on mental health during pregnancy is still being understood.
Using baseline data from P3 Cohort participants collected between 2021 and 2023, the study found that 23% of participants reported symptoms of depression during pregnancy. Relationship challenges- such as dissatisfaction, conflict, and lack of social support- were linked to higher rates of depression. However, broader pandemic-related stressors, including financial strain, isolation, and uncertainty, had an even greater impact.
These results suggest that while healthy relationships are important, external stressors can play a major role in mental health during pregnancy. The findings highlight the importance of strong social and emotional support systems, especially during times of increased stress.
Verschuur AS, van Wezel-Meijler G, Low S, Nijholt IM, Metcalfe A, Skiffington J, Slater DM, Bergeron A, Fiedrich E, Boomsma MF, Tax CMW, Leemans A., Leijser LM. Trends in Term-Equivalent Age Brain Volumes in Infants Born Across the Gestational Age Spectrum. Children (Basel). 2025;12(8):1026. [P3 Brain Health Substudy Data]
This study published in Children (Basel) used data from the P3 Cohort Brain Health to assess the effect of gestational age at birth on brain volumes at term-equivalent age in infants without overt brain injury born across the GA spectrum.
The main findings show that lower gestational age is significantly related to larger cerebrospinal fluid volume. Trends of higher gestational age with larger volume of brain tissues are seen.
This study found that lower gestational age was associated with brain tissue volumes and significantly larger cerebrospinal fluid volume.
These results suggest preterm birth may affect early brain growth and contribute to neurodevelopmental challenges encountered by preterm-born children.
2022
Pekarsky C, Skiffington J, Leijser LM, Slater D, Metcalfe A. 2022. Social Media Recruitment Strategies to Recruit Pregnant Women into a Longitudinal Observational Cohort Study: Usability Study. J Med Internet Res. 24(12):e40298.
In this study published in J Med Internet Res P3 researchers evaluated the effectiveness of Facebook, Twitter, and Instagram in recruiting a representative sample of pregnant women for the P3 Cohort.
This study found that paid social media advertisements (especially Facebook and Instagram) are feasible and cost-effective methods for recruiting a large sample of pregnant women for survey-based research.