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So you got a baby and lost your memory. Wait, why did I start talking about that? Call it Pregnancy Brain, Mommy Brain, Momnesia…they all describe a state of impaired memory or fuzzy-headedness that many new moms experience. It can start way before birth. When I first started to notice how forgetful I had become during my first pregnancy, I asked my doctor about it in alarm. He scoffed and said it was just my imagination. Meanwhile, his nurse rolled her eyes and commiserated with me as soon as he’d left. We both – along with every one of my pregnant or new mother friends – knew something was up. We were walking into a room only to forget why we’d done so. We were losing our keys, forgetting to write a grocery list and then losing the list that we did remember to write. We were dressing ourselves in mismatched socks and worrying that we’d drive off and leave our baby in her seat on the sidewalk. So what is happening to us? As I researched the phenomenon, I discovered there is no surprise that women notice changes in cognition during pregnancy, which is apparently an important time for a woman’s central nervous system development. However, there seems to be relatively little research about how pregnancy changes a mother’s brain, most of it has been conducted with rodents, and lots of it is contradictory. One helpful source of information is a literature review published in Current Directions in Psychological Science, a journal published by the Association for Psychological Science. Psychologist Laura Glynn of Chapman University was one of the authors, along with Curt Sandman of the University of California, Irvine. The article reviews research that suggests that reproductive hormones are readying a woman’s brain for the demands of motherhood. Glynn suggests this might be why moms wake up when the baby stirs but dads continue to sleep. Hormones In fact, surging hormone levels go a long way toward explaining Mommy Brain. During pregnancy, the brain is subjected to between twenty and forty times more progesterone and estrogen. And these hormones affect all kinds of neurons in the brain, including, researchers think, spatial memory. By the time the baby is born, huge surges of oxytocin – which cause the uterus to contract and milk production to begin – are also affecting the woman’s brain circuits. In an article published in 2010 in the journal Behavioral Neuroscience (American Psychological Association), researchers reported that the brains of new mothers actually expand in areas linked to motivation and behavior. Led by neuroscientist Pilyoung Kim, PhD, now with the National Institute of Mental Health, the authors speculated that hormonal changes right after birth, including increases in estrogen, oxytocin, and prolactin, may help make mothers’ brains susceptible to reshaping in response to their babies. The researchers performed baseline and follow-up high-resolution magnetic- resonance imaging on the brains of nineteen women who gave birth at Yale-New Haven Hospital. A comparison of images taken two to four weeks and three to four months after the women gave birth showed that gray matter volume increased by a small but significant amount in various parts of the brain. In adults, gray matter volume doesn’t ordinarily change over a few months without significant learning, brain injury, or illness, or major environ- mental change. The areas affected support maternal motivation, reward, and emotion processing; sensory integration; and reasoning and judgment. In particular, the mothers who most enthusiastically rated their babies as special, beautiful, ideal, perfect, and so on were significantly more likely to develop bigger mid-brains than the less awestruck mothers in key areas linked to maternal motivation, rewards, and the regulation of emotions. The mothers averaged just over thirty-three years of age and had an average of eighteen years of formal education. All were breastfeeding, nearly half had other children, and none had serious postpartum depression. Although these early findings require replication with a larger and more representative sample of women, they raise intriguing questions about the interaction between mother and child (not to mention father and child). The authors wrote that intense sensory-tactile stimulation of a baby may trigger the adult brain to grow in key areas, allowing mothers, in this case, to “orchestrate a new and increased repertoire of complex interactive behaviors with infants.” Further study using adoptive mothers could help “tease out effects of postpartum hormones versus mother-infant interactions,” said Kim, and help resolve the question of whether the brain changes behavior or behavior changes the brain – or both. A side effect of the research may be to study postpartum depression, and to help women who experience it. The authors said that postpartum depression may involve reductions in the same brain areas that grew in mothers who were not depressed. “The abnormal changes may be associated with difficulties in learning the rewarding value of infant stimuli and in regulating emotions during the postpartum period,” they wrote. Not Just Hormones Aside from hormones, there are other valid reasons why pregnant women as well as new moms may not feel razor sharp. Pre-birth, there is lots to do – finishing up at work in preparation for maternity leave; preparing older children for the birth, doctor or midwife appointments; and so on. Once baby is born, life changes immeasurably and, if there are other children in the family, lots of conflicting needs and related stress. Add to that the lack of a good night’s sleep, and memory lapses can be expected.
Like my own doctor did, some academics dismiss Mommy Brain as a myth, and some think it’s a sexist one. Dr. Ros Crawley, who led a team of researchers from Sunderland University in the U.K. in 2003, suggested that negative mood swings were causing pregnant women’s reported memory problems, or that the reason could be “cultural expectations of impairments which make women more aware of forgetting things and attributing such mistakes to their pregnancy.” Crawley hypothesizes that pregnancy is associated with cognitive deficits, not because of the effect of being pregnant per se, but simply because pregnancy is a major life event involving huge emotional and practical upheaval. Various studies have linked the cognitive deficits of pregnancy with sleep deprivation, fatigue, and depression. Crawley is quoted in an October, 2010 article in The Psychologist (British Psychological Society) by Christian Jarrett as saying, “Maybe you’d find something similar if you looked at another major life event like bereavement where those factors might be contributing. But because it’s fairly plausible that pregnancy as a physiological event might have an effect on cognition – because of the hormonal changes – I suspect that’s why people have looked for that more intently, in terms of pregnancy itself.” In an attempt to sort out the controversy, Julie Henry, a psychologist at the University of New South Wales in Sydney, Australia, led a meta-analysis of the existing research in 2007. She found that research on the topic falls mainly in two categories: those studies that asked pregnant women whether they have any problems, and others that used objective measures. The studies using objective tests of memory and attention during pregnancy have proven to be inconsistent. For every study that reports an apparent deficit, there’s another that turns up a negative result. Henry and her colleagues noticed that many of the objective studies had small sample sizes that lacked the power to detect relatively subtle differences in brain functioning. And some of the inconsistency could be methodological. On the other hand, the self-reporting study results are strikingly consistent, says Henry. Across the board, approximately two thirds of women report having some kind of memory or attention problems that they attribute to their pregnancy. Does it Matter? Whether or not there is a scientific basis for your forgetfulness, it is real if you experience it. Some of the research unfortunately seems to conflate short-term memory challenges with intelligence. They are not the same thing; having a baby does not make you ditzy or dumb, even though it might feel that way on your worst day of new parenting. Look at it this way: New parenthood is an emotionally intense time and, for first-time mothers, a time of intense learning. And with those experiences, growth – emotional and intellectual – is inevitable. Additionally, you’re learning important skills like multitasking, time management, responsibility, negotiation, and emotional intelligence. So try to get some sleep, hang your keys on a hook by the door, and concentrate on remembering where you put the baby. You’ll be fine.
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