JMIR Publications

ABSTRACT

Background:

Pregnancy and childbirth involve significant health challenges, including preventable maternal deaths, severe complications, and disparities tied to social determinants, underscoring the need for improved maternal care and support. Pregnancy, a complex physiological state, could benefit from a more comprehensive, continuous care model that captures dynamic changes and enhances maternal-fetal outcomes.

Objective:

This large-scale, real-world, high-density study uses wearable data to investigate maternal biobehavioral trajectories (sleep, temperature trends, cardiorespiratory, and activity data) for pregnancies leading to loss, preterm, and term births, exploring how demographics factors like age and body mass index (BMI) affect these trajectories.

Methods:

Retrospective observational analysis of pregnancies from a large sample of 10,319 18–51-year-old female Oura Ring users (324 preterm births, 5039 term births, 4955 pregnancies ending in loss before 20 weeks of gestation). Oura biobehavioral data were analyzed across a 64-week window encompassing 8 weeks prior to the estimated start of pregnancy (the first day of the last menstrual period), through pregnancy and postpartum (up to 56 weeks following pregnancy start), via Generalized Estimating Equation (GEE) statistical modeling.

Results:

The outcomes highlight the complex dynamics underlying changes in participants’ sleep, temperature trends, cardiorespiratory, and activity data throughout pregnancy. Oura biobehavioral data trajectories followed non-linear trends, with significantly larger fluctuations occurring around the beginning and end of pregnancy. Most changes fell within a magnitude of 1–2 standard deviations from the pre-pregnancy baseline, with a notable increase in participants’ nighttime wake time around birth, exceeding 3 standard deviations above baseline (all P-values < .001). Age and BMI influenced the trajectories of change across all biometrics (all P-values < .01); however, the magnitudes of these effects were generally small and may not be of practical relevance. In pregnancies that end in loss, distinct deflections in Oura biobehavioral metrics emerge and become apparent approximately one week before the pregnancy end.

Conclusions:

The distinct behavioral and physiological changes that accompany pregnancy reflect its complexity, involving extensive biological, hormonal, and behavioral adaptations coordinated to optimize maternal and fetal development. A deeper focus on normative physiological changes and their underlying mechanisms has the potential to advance maternal-fetal medicine, improve clinical outcomes, and address key gaps in scientific understanding.