Note: This post originally appeared March 14, 2014, on a blog that was a project for dietetics school. I will be adding posts from that blog in order to consolidate my posts on one site.
It’s been a very exciting week for our little crew. This week, we learned that we will be welcoming…a boy! Since we already have two girls, we are waddling (somewhat literally, for me these days) into unknown territory, but we are thrilled to meet this little guy in early August.
In anticipation of our big ultrasound, I found myself looking for any clues as to what I might be having. I turned to my new favorite pregnancy book to see if I could gain any insight.
Origins: How the Nine Months Before Birth Shape the Rest of Our Lives provides a fascinating look at the fetal origins theory. The fetal origins theory examines how the fetal environment affects health throughout the life span. An example of this is research suggesting that infants born weighing less than 7.5 pounds are more likely to develop cardiovascular disease later in life. (1)
In Origins, author Annie Murphy Paul, a science writer for the New York Times Magazine, Slate,Discover and other publications, examines pregnancy-related research to see what insights it can offer into her own pregnancy. I first read the book during our beach vacation in January, and I’ve been having a lot of fun trying to apply some of the research to my past and current pregnancies.
One of the sections that I kept thinking about after I finished the book examines the role of fetal sex in mom’s appetite. Murphy Paul describes a 2003 study of more than 300 moms, in which moms carrying male fetuses ate about 200 calories more per day that moms carrying female fetuses. Researchers could not explain exactly why that may be; however, they mentioned the possibility that testosterone from fetal testicles could trigger hunger in the mom. (2,3)
Because I’ve been unbelievably hungry this entire pregnancy, I have wondered since reading this if it may be true. Now that I’ve confirmed that I’m having a boy, I decided to further investigate the idea that fetal sex influences mom’s appetite. After reading the study cited in Origins, I searched to see if anyone had expanded on it since its publication 11 years ago.
Shortly after, Simon Langley-Evans, nutrition lecturer at University of Nottingham, wrote a counterpoint to the original study. Langley-Evans conducted his own study of 300 pregnant women and found no difference in calorie intake between moms carrying boys and moms carrying girls (4). He reinforced his findings by noting that, if boys really needed more calories, male newborns would see worse outcomes from poor maternal nutrition than girls (they don’t).
Further, a 2003 letter to the British Medical Journal (which originally published the study in question) editor raised the question of whether a mom’s knowledge of baby’s gender causes her to eat more if she is having a boy. Many cultures subscribe to a “feed the growing boy” mentality, and this may have biased the study (5).
What does this mean for you if you are expecting a boy? Not a lot. The jury is clearly still out as to whether male fetuses need more energy, and the last thing you should do if you are having a boy is to use this study as an excuse to eat more. Regardless of sex, if you are finding yourself hungrier than normal, try to fill up on nutrient-dense foods as much as possible.
Note: Origins, like pretty much everything else in the world, is available on Amazon. It is a quick, fun read, and I highly recommend it if you are interested in the fetal origins theory.
Another Note: Does this post include a nutrition-related term you don't know? Click here for some pregnancy and nutrition definitions.
1. Brown, Judith E., and Janet S. Isaacs. Nutrition through the Life Cycle. S.l.: Wadsworth Cengage Learning, 2011. Print.
2. Paul, Annie Murphy. Origins: How the Nine Months before Birth Shape the Rest of Our Lives. New York: Free, 2010. Print.
3. Tamimi, Rulla M., Pagona Lagiou, Lorelei A. Mucci, Chung-Cheng Hsieh, Hans-Olov Adami, and Dimitrios Trichopoulos. "Research Pointers: Average Energy Intake Among Pregnant Women Carrying A Boy Compared With A Girl." JSTOR. N.p., 7 June 2003. Web. 13 Mar. 2014.
4. Langley-Evans, Simon, and Alison Langley-Evans. "Energy Intake in Pregnant Women Carrying Boys or Girls: Difference Is Chance Observation." National Center for Biotechnology Information. U.S. National Library of Medicine, 13 Sept. 2003. Web. 13 Mar. 2014.
5. "Energy intake in pregnant women carrying boys or girls." British Medical Journal 13 Sept. 2003: 621+. Academic OneFile. Web. 13 Mar. 2014.