ABSTRACT
Background: Certain forms of prenatal maternal stress (PNMS) are risk factors for preterm birth and low birthweight. In the context of the COVID-19 pandemic, two components of PNMS, objective hardship and subjective distress, may be differentially associated with birth outcomes. We aimed to determine the association of pandemic-related objective hardship and subjective distress with birth outcomes, and we explored moderating factors of objective hardship. Methods: Australian women who delivered during the pandemic completed online questionnaires at baseline and at two months postpartum, including self-reports of pandemic-related objective hardship, subjective distress and birth outcomes. We conducted linear regressions with objective hardship and subjective distress controlled for objective hardship as predictor variables and gestational length and birthweight as outcome variables. Moderation of objective distress by subjective distress, infant sex, and change in diet was evaluated by adding two-way interaction terms. Results: The sample included 2285 women (51.6% male infants, 48.0% female and 0.4% unreported sex). Age 30-34 years was the most frequent maternal age category. No associations between maternal objective hardship or subjective distress with gestational age at birth or birthweight were identified. After controlling for objective hardship, female infant sex and self-reported improvement in maternal diet were significantly associated with lower birthweight (β = -0.090 and -0.069, respectively), but there were no significant interactions with objective hardship. Conclusions: Objective hardship and subjective distress were not associated with birth outcomes. Other factors such as change in diet and infant sex may be more important for risk stratification in this context.