The Incredible Shrinking Brain

. . . Or, how I got pregnant and lost my mind

We were on our way to the auto-repair shop. My husband led the procession, his car freshly smashed from a minor spin-out. I was following closely behind in our second car. We stopped at a red light. When the light turned green, my husband hesitated for a moment. Because I was living in a separate universe I call “Planet Pregnant,” I didn’t. The front end of my car fused slowly into the rear end of his. Although no one was hurt and the damage was slight, we ended up putting two cars in the shop that afternoon instead of just one. As the baby developed and my belly grew to five times the size of my head, my brain size seemed to decrease proportionately. The term “pea-brained” began to take on a new, personal meaning for me. And, of course, it was all my husband’s fault: “Honey, you shrank my brain by getting me into this mess,” I told him. As a matter of fact, the ineptitude that seems to accompany so many pregnancies — forgetfulness, a tendency to lose things, an inability to concentrate and general spaciness — apparently is an unavoidable biological phenomenon. According to results from two recent studies, the maternal brain literally becomes smaller late in a woman’s pregnancy.

Studies Chart Shrinkage Using magnetic resonance imaging, a team of British researchers led by London anesthesiologist Anita Holdcroft, M.D., recently scanned the brains of 10 pregnant women who were in their final two months of pregnancy and then again at two and six months postpartum. Holdcroft’s original objective was to look for swollen air passages and changes in brain size in pregnant women with preeclampsia. She was shocked to learn that instead of swelling, the subjects’ brains were smaller during pregnancy than after delivery. “Brain cell volume actually decreases in pregnancy,” Holdcroft says. “The changes are not that big, but they are measurable.” Speculating that hormonal alterations of brain metabolism are responsible for the shrinkage, Holdcroft found similar changes in brain volume in menstruating women. She since has launched a larger study of pregnant women to test the hormone theory.

Pregnancy-Induced Slowness The link between brain contraction and so-called “pregnancy-induced slowness” is not clear, but research conducted earlier this year by University of Southern California psychologist J. Galen Buckwalter, Ph.D., suggests that pregnant brains not only shrink, but they also suffer impaired cognitive functioning. Buckwalter, who has likened pregnancy to “a big assault on the brain,” tested 19 highly educated pregnant women whose average IQ was about 110. He found that all of the subjects had experienced depressed functioning of their concentration and short-term memory. In addition, the women’s ability to learn and retain new information was reduced. In a test of how well pregnant vs. nonpregnant women with similar IQs learned new information, the pregnant subjects scored in the lowest 5 percent. Buckwalter will test the group again at one to two years postpartum. Like Holdcroft, Buckwalter is studying the possible connection between the concentrations of pregnancy-altered hormones and the mental glitch.

Real-Life Proof Laboratory studies are fine, but real life — mine, for example — offers the best proof. Take my recurring theme while pregnant: repeatedly missing obstetric appointments. This did not surprise the unflappable receptionist at my doctor’s office. In fact, when I showed up for one phantom appointment (nothing was scheduled for me that day), she told me about one patient who sat in her car for 20 minutes to warm the engine up before she realized she had never turned the key. Worse, perhaps, is the sudden inarticulateness that can come with pregnancy. A pregnant friend of mine gave her husband this long-winded answer when he asked if she’d seen his keys: “They’re on that thing between the living room and the kitchen, and it’s long and it’s made of wood and about 32 inches high.” Translation: the counter. Naturally, all this is embarrassing, wastes time and results in some intriguing explanations for lamebrainness. Um. I can’t think or speak because I’m making my baby’s eyeballs today. It all seems fairly innocuous until you realize that some mental lapses could bankrupt you. One woman I know kept adding money ($300 and up) to her checkbook balance instead of subtracting when she paid bills. Another pregnant friend’s math impairment caused her to lose count while attempting to organize 89 stock photos at work. “It was like I forgot how to count,” she groused. Someone else finally did it for her. If one brain is pregnant, it’s good to have a normal-size one around as backup.

Don’t Worry — It’s Temporary Brain shrinkage is part of the many normal body changes that take place in pregnant women, according to Holdcroft’s study. Thankfully, the gray matter seems to plump back up to normal size sometime after childbirth. Until then, pregnant women can compensate for their crippled brains by making lists, pasting notes to their foreheads, sending themselves e-mail and appealing to the kindness of strangers. Excuse me, but could you tell me if the checker gave me the correct change, because I am too pregnant to know the difference. I’m sure researchers would agree that we need to issue some sort of warning to the public. Perhaps an open letter in the form of a T-shirt: “Baby on board. Brain back in nine months.”