Iím so pleased to announce we are expecting our second child, who is due to arrive in November! It has been almost three years since my first trimester with my son Joshua, and all those early pregnancy symptoms are back and seem to be more extreme than I remember them the first time around. (Or maybe I just have a selective memory.) I have mild morning sickness, which is really more like all-day sickness, but itís just a persistent feeling of mild queasiness instead of actual sickness. Iím also exhausted, but I think thatís because I have a toddler to care for so I donít get to rest much. And then thereís one symptom that I had completely forgotten about: shortness of breath.
My classroom is on the third floor of a big school. Itís actually the furthest possible classroom from the parking lot, and itís a long walk to get there every morning. Iím completely winded by the time Iím halfway up the second flight of stairs and any conversation Iím having stops abruptly. It also takes a long time for me to catch my breath after I get to my classroom. Since Iím a science nerd and Iím fascinated by anatomy and physiology, I decided to do a little research about the changes to the cardiovascular and respiratory systems during pregnancy.
The Heart And Lungs Of Pregnancy
I know that growing a baby requires energy and oxygen, and I remember reading somewhere that a pregnant womanís blood volume increases. A quick internet search on that topic turned up Ciliberto and Marxís†Physiological Changes Associated with Pregnancy, which was published in the journal Physiology. I love finding full-text articles online for free, and this one is a wealth of information. According to Ciliberto and Marx, a pregnant womanís blood plasma volume increases 40-50%, while her red blood cell mass increases 20-30%. Red blood cells contain hemoglobin, which carries oxygen around the body, and all this extra blood helps to give the developing baby oxygen, remove carbon dioxide and provide nutrients. Even with the increase in blood volume, a healthy womanís blood pressure typically doesnít rise during pregnancy.†A mom-to-beís heart also changes during gestation. The heart tends to enlarge slightly, some women develop a murmur, and it even shifts to the left to accomodate the growing baby. Heart rate increases by about 15%.
The stuffy nose that some women experience during pregnancy is due to a progesterone-induced swelling of the air passages. A momís respiratory rate also increases by about 15%, or 2-3 breaths per minute, which helps her get enough oxygen even though her lung volume slightly decreases thanks to the growing baby. So even though I feel like Iím sucking wind by the time I get to the third floor, itís just my bodyís way of making sure my baby gets enough oxygen.
Pollutants And Pregnancy
Every time I feel that shortness of breath, I think about all of the pollutants that I could be breathing in. A†developing fetus is especially sensitive to toxins in the air, and I want to protect my baby as much as possible. Women who live in urban areas, where there is poorer air quality, are more likely to have babies born†prematurely or with a lower birth weight.
I may joke that Iíd like to have a smaller baby next time, since my son was a full nine-and-a-half pounds, but Iím only kidding. Iíd rather have a healthy ten-pounder than a seven-pound baby who is sick. Since babies donít really need to breathe until after theyíre born, the respiratory system matures late in pregnancy and premature babies often experience respiratory distress, which can lead to a lifetime of respiratory problems like†asthma. Doesnít it make sense that a developing baby who is exposed to toxins from air pollution will grow up to have respiratory problems? Shouldnít we protect our children from a sick future?
Good Choices Arenít Enough
Since I already have a son, Iíve often been asked if I would like to have a girl this time around. My answer is the same old cliche-†ďAll we want is a healthy baby.Ē Donít we all want healthy children? Throughout my pregnancy (and even before) I choose not to smoke, not to consume alcohol, and I even avoid nail polish because of the VOCs. I take the recommendations to skip deli meat, sushi and unpasteurized cheese. Why, then, should I be forced to breathe in contaminated air that we know can harm a developing baby?
I make good choices for myself but Iíd like some help from our legislators. I canít hold my breath every time I go to an area that may have less than perfect air quality.
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