Evidence for cognitive plasticity during pregnancy via enhanced learning and memory

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

Abstract

Introduction. Fueled by anecdotal reports of “poor memory” from pregnant and postpartum women, decades of research on “baby brain” have looked for cognitive deficits broadly, and memory impairments specifically, associated with pregnancy. Apart from a few limited areas of small performance decrements, such studies have largely come up short. This discrepancy between objective and subjective reports of memory during pregnancy suggests that the oft cited “baby brain” may actually be capturing memory adjacent processes, e.g., redistributed attention towards more ecologically relevant stimuli and tasks. Unfortunately, few studies have examined memory in pregnant women using ecologically relevant stimuli. In the current study we examined a form of memory akin to that which is improved during pregnancy in rodents – spatial associative memory (object paired with scene) using objects that differed in their ecological relevance to the experience of pregnancy (baby vs. adult).

Hypotheses. We hypothesized that pregnant women would either show evidence for attentional reorienting (reflected as better performance on the baby than adult stimuli) and/or evidence for a general cognitive enhancement (better performance than never pregnant women on both stimuli types).

Study population. There were two groups of women who were seen over two waves spaced 4 weeks apart. The first group was N = 74 women who were in the 32nd week of pregnancy (18-40 years old, mean age = 28.92 years, N = 17 with their first child), of whom N = 52 returned at 36 weeks pregnancy. The second group was N = 88 nulliparous women who were between 18-45 years old at wave 1 (mean age = 30.58 or 31.57 years – depending on whether they were seen in person or online due to COVID-19), of whom N = 60 returned 4 weeks later for wave 2.

Methods. Wave 1 involved participants completing questionnaires assessing sleep quality and depression symptoms, as well as a memory task that involved passively viewing scenes paired with objects (see Figure 1), followed by an immediate memory test (recognition of objects alone and pairing objects with scenes). Wave 2, which was 4 weeks later, involved the same memory test a second time (to assess remote memory).

Results. We saw evidence for both attentional reorienting and general cognitive enhancement in memory for pregnant, relative to nulliparous, women. In terms of attentional reorienting, we saw that pregnant women showed equal learning about ecologically relevant (baby) vs. less relevant (adult) objects, t(140) = 1.24, p = .217, d = -.10, whereas the nulliparous women showed worse learning to baby than adult objects, t(140) = 3.65, p = .001, d = .31. Moreover, pregnant women performed marginally better than the nulliparous women for learning about baby objects, t(155) = 1.96, p = .052, d = -.31. However, this boost in learning did not transfer to enhanced long-term memory for those specific objects. In terms of a general cognitive enhancement, we saw that pregnant women exhibited higher performance accuracy overall than nulliparous women on the object-scene pairing at wave 2, F(1, 90) = 3.96, p = .050, partial η2 = .04, (better associative memory retention); see figure 2. Findings were robust to controlling for sleep, parity, and depression scores.

Authors

• Bridget Callaghan, The University of California, Los Angeles
  Presenting Author

• Clare McCormack

• Nim Tottenham, Columbia University

• Catherine Monk, Columbia University Irving Medical Center