Quentin Smith and Dr. Brock Kirwan, Department of Pyschology
Pregnancy is a complicated biological process that is often accompanied by reported cognitive changes among pregnant women. Pregnant women commonly report diminished cognitive functioning during pregnancy, with “forgetfulness” and “a poor memory” as the most common complaints (Brett & Baxendale, 2001; Crawley, 2002). However, despite these anecdotally reported deficits, the evidence suggesting memory impairments in pregnancy are equivocal. In a recent meta-analysis of 14 studies of memory in pregnancy, it was concluded that pregnancy disrupts some, but not all, memory processes (J. D. Henry & Rendell, 2007). In particular, memory tasks that place high demands on executive cognitive control seem to be impacted. Examples of memory processes requiring executive cognitive control include free recall (the recollection without any cues of previously studied material) and prospective memory (remembering to perform a task in the future).
Prospective memory is traditionally categorized as either event- or time-based. Event-based prospective memory refers to when the intended action is triggered by some external cue (e.g., give a telephone message to a co-worker when she returns to the office), while time-based prospective memory refers to performing the intended action at a certain time (e.g., making a telephone call at a specific time in the future).
Funded by ORCA, we performed a study to evaluate memory performance of pregnant women where we evaluated event-based prospective memory by utilizing a prospective memory task embedded within a separate task. In the ongoing task, subjects were presented with a series of five-letter strings and asked to determine if the letters in the 2nd and 4th positions were the same or if they were different. We administered questionnaires (The Pittsburgh Sleep Quality Index, The State Trait Anxiety Index, and the Beck Depression Inventory-II) in order to assess and control for possible ameliorating factors such as depression, anxiety, and quality of sleeping during the weeks prior to testing. We hypothesized that pregnant women would be impaired in the prospective memory task relative to non-pregnant controls.
The prospective memory task was modified after the methods employed by Bisiacchi and colleagues (Bisiacchi, Schiff, Ciccola, & Kliegel, 2009) and consisted of three separate conditions: the ongoing condition, the prospective memory condition, and the distractor condition. In the ongoing condition, participants were asked to determine if the letters in the second and fourth positions of five-letter strings were the same (e.g., NGNGN) or if they were different (e.g., NGNWN). Responses were given with the ‘C’ (same) and ‘M’ (different) keys. Letters in the first, third, and fifth positions were always identical. The prospective memory condition consisted in the second and/or fourth position being occupied by the letter ‘B’ (e.g., KBKLK or YBYBY). In these trials, rather than pressing ‘C’ or ‘M’, participants were instructed to press the ‘B’ key.
We found no evidence for an effect of pregnancy on prospective memory performance. Even when controlling for differences in sleep quality and depression, pregnant subjects performed equally as well as non-pregnant subjects on the prospective memory task. Our data are consistent with other studies that have failed to demonstrate an impairment in laboratory-based tests of prospective memory in pregnancy. Onyper and colleagues (2010) tested a group of women in their second or third trimester of pregnancy and a group of non-pregnant controls using a prospective memory task. For the task, the women were instructed to remind an experimenter to check the phone for an important message, but to do so only after completing a battery task first. While pregnant women took longer to remind the experimenter, there was no significant difference in the likelihood of remembering to remind the experimenter between pregnant and non-pregnant women. Similarly, Cuttler and colleagues (2011) demonstrated that pregnant women were not impaired on a laboratory-based test of prospective memory. However, Cuttler and colleagues also administered a series of field measures of prospective memory (e.g., asking participants to place telephone calls or mail an item after participating in the laboratory experiment). The authors report significant differences on two out of three of the field measures.
Pregnancy is a complicated biological process and cognitive changes associated with pregnancy have been demonstrated in numerous studies. We investigated the relationship between pregnancy and prospective memory with an eye toward the effects of depression, anxiety, and sleep quality on memory performance. Although we did not observe a relationship between these factors and prospective memory performance, continued research will be needed to account for the effects of pregnancy on prospective memory in field trials.
- Bisiacchi, P. S., Schiff, S., Ciccola, A., & Kliegel, M. (2009). The role of dual-task and task-switch in prospective memory: behavioural data and neural correlates. Neuropsychologia, 47(5), 1362-1373.
- Brett, M., & Baxendale, S. (2001). Motherhood and memory: a review. Psychoneuroendocrinology, 26(4), 339-362.
- Crawley, R. (2002). Self-Perception of Cognitive Changes during Pregnancy and the Early Postpartum: Salience and Attentional Effects. Applied Cognitive Psychology, 16, 617-633.
- Cuttler, C., Graf, P., Pawluski, J. L., & Galea, L. A. (2011). Everyday life memory deficits in pregnant women. Can J Exp Psychol, 65(1), 27-37.
- Henry, J. D., & Rendell, P. G. (2007). A review of the impact of pregnancy on memory function. J Clin Exp Neuropsychol, 29(8), 793-803.
- Onyper, S. V., Searleman, A., Thacher, P. V., Maine, E. E., & Johnson, A. G. (2010). Executive functioning and general cognitive ability in pregnant women and matched controls. J Clin Exp Neuropsychol, 32(9), 986-995.