Given the inconsistency between subjective and objective reports on hyperosmia, research suggests that pregnant women don’t necessarily have a stronger sense of smell, but are perhaps better at identifying smells. Interestingly, though, even in a study where six different scents were tested, there was no difference in detection threshold between the two groups. Another study reported that, relative to non-pregnant women, pregnant women are particularly sensitive to odors such as cooking foods, cigarette smoke, spoiled food, perfumes, and spices.Ī few studies have examined scent detection thresholds (the smallest volume of air that still results in odor detection) in pregnant versus non-pregnant women. Subjectively, around two-thirds of women rate their sense of smell as stronger than usual while pregnant. Although anecdotes of hyperosmia have existed for a century, scientific literature on the topic is sparse. Why does my sense of smell become so much stronger?Īccording to many women, a heightened sense of smell, called hyperosmia, is one of their earliest signs of pregnancy. It’s a sensitive system, and despite how crappy it makes mom feel, morning sickness likely provides an evolutionary advantage for the baby’s development. Rather, morning sickness is likely more associated with foods prone to microorganisms in the times before refrigeration (like meats), or bitter vegetables, the taste of which signaled “poison!” to our early human ancestors. Of course, these so-called toxins are really not toxic at all to healthy adult women, and the placenta does a superb job of filtering out waste and fighting infection. Many women also naturally tend to be more “turned off” to eating meat, fish, and certain plants during this time. This “toxin theory” is supported by several pieces of evidence, including the fact that morning sickness is more common in societies with “risky foods,” that it only occurs in humans (we have very broad diets, after all), and that more severe morning sickness is associated with lower rates of miscarriage. Research has shown that the area postrema has receptors for hCG, which may explain why it’s particularly sensitive during pregnancy. Importantly, the area postrema lacks a blood-brain barrier, which means it can detect toxins in the bloodstream and cerebrospinal fluid. Vomiting is controlled by an area in the hindbrain called the area postrema. A more recent theory states that vomiting during early pregnancy serves a beneficial function by ridding the body of food that may unsettle this important developmental stage.Īrea postrema, labelled 3rd from the bottom. The central nervous system critically forms during this time, and this delicate process is highly susceptible to disruption by toxins circulating in the mother’s bloodstream. We do know that the first trimester is an important time in fetal development.
The correlation is interesting, but it doesn’t explain why morning sickness happens. Studies have shown a temporal relationship between hCG and morning sickness, meaning that levels of hCG in the bloodstream and frequency of vomiting appear to peak at the same time. The most popular theory is that morning sickness is the body’s reaction to the increase in the pregnancy hormone human chorionic gonadotropic (hCG). The cause of morning sickness isn’t entirely clear. For most women, morning sickness goes away after around 18 weeks. Thrust into the limelight as a result of Kate Middleton’s hospitalizations, around 1% of pregnant women experience more severe, prolonged morning sickness called hyperemesis gravidarum, which can result in dehydration, weight loss, and require serious medical attention.
More than half – perhaps up to 90% – of pregnant women experience nausea or vomiting to some degree, particularly in the morning. She then followed with, “I was going to ask you to explain something else to me, but I totally forgot what it was.”ĭoes “pregnancy brain” actually exist? There’s no doubt that many changes are happening to a woman’s body during pregnancy, but how do these changes affect (or originate in) the brain? To answer my friend’s question – and in an effort to address whatever else she was forgetting at the time – here is Part 1 of my expectant mom’s guide to the crazy neuroscience of pregnancy. A few months ago, my friend asked me, “Why have I become so forgetful since I became pregnant?” I told her I didn’t know, but that I’d look into it and write an article for her.
0 kommentar(er)
