Evidence of subjective, but not objective, cognitive deficit in new mothers at 1-year postpartum

• In Event: Advances in Understanding Maternal Memory Processes from Pregnancy to Postpartum: Risk-Buffering, ‘Baby-Brain,’ and Ecological Approaches

Abstract

“Baby-brain” is a colloquial term that refers to cognitive decline experienced by women during the transition to motherhood (pregnancy and the postpartum period) and is self-reported by approximately 80% of expectant mothers. Subtle memory deficits have been consistently found during pregnancy, including objective deficits in working memory, recall, processing speed, and general cognition, as well as lower self-rated memory. However, there is considerably fewer studies investigating cognition in the postpartum period, and evidence for differences in cognitive performance between postpartum versus non-postpartum women is mixed. When assessing the extant literature as a whole, it is clear that the number of studies showing non-significant changes or differences in cognitive function in the postpartum period outweigh those showing significant cognitive deficits. The endurance of cognitive deficits into the postpartum period therefore remains unclear in the scientific literature. Poor understanding about the time-course of cognitive changes in early motherhood represents a shortcoming in maternal healthcare, and has implications for how women’s cognitive abilities in the postpartum period are perceived by society, employers, and themselves.

In early motherhood, we investigated cognitive performance in 43 first-time mothers at one year postpartum, and 43 age- and education-matched nulliparous women. Mothers and non-mothers showed no significant differences on measures of objective cognition (verbal memory, working memory, processing speed or theory of mind; Table 1). Despite the absence of objective differences, mothers self-reported significantly worse subjective memory than non-mothers. To interpret this discrepancy, we investigated relationships between subjective memory, objective memory, and wellbeing.

Subjective & Objective Memory: Mothers, but not non-mothers, showed a positive correlation between subjective and objective measures of memory, indicating mothers are ‘in-tune’ with their memory performance (Figure 1a,c). We speculate that mothers’ increased awareness of their memory performance may arise from two factors; a greater daily cognitive load (i.e., an increase in the number of items and tasks to remember in daily life), and an increased attention to memory lapses. With an increased cognitive load, there become more opportunities to forget an item or task. Memory errors in the postpartum period also carry heavier consequences, making memory lapses more salient. Therefore, pregnancy and early motherhood may make women more attuned to their functioning through a higher sensitivity to minor memory or concentration lapses, which encourages mothers to evaluate and re-evaluate their subjective memory regularly.

Subjective Memory and Wellbeing: Mothers also demonstrated a positive relationship between subjective memory and wellbeing (sleep, anxiety, and depression), where better wellbeing correlated with higher subjective memory, which was not apparent in non-mothers (Figure 1b,d). The results suggest that poorer sleep, higher anxiety, and higher depression are related to reports of poorer subjective memory in mothers.

Our results refute the phenomena of “baby-brain” deficits at one year postpartum, with no evidence of cognitive differences between mothers and non-mothers, and suggest that measuring and controlling for differences in sleep, depression, and anxiety is essential when assessing cognition in the postpartum period, and providing appropriate support for new mothers who are experiencing poor wellbeing.

Authors

• Edwina R Orchard, Yale University
  Presenting Author

• Phillip GD Ward, Monash University

• Gary F Egan, Monash University

• Sharna D Jamadar, Monash University