Morris - maternal physiologic adaptations

So the pregnancy changes that you experience as a result of all of these hormonal influences that are new to your body actually do allow you to accommodate to the extra work your body needs to do. So for example, our basal metabolic rate is higher when we’re pregnant. Our stroke volume or the amount of blood that’s pumped through our heart per minute is higher and our minute ventilation volume is higher and all of those changes allow us to deliver more oxygen to the baby. If you have a woman with either major cardiovascular or respiratory illnesses for example, they can’t accommodate the same way as a healthy woman can and you are more likely to have the growth restriction. Gastric emptying is delayed when we are pregnant so when we’re not pregnant we can empty a big meal out of our stomach in about an hour and a half. And when you’re pregnant it takes about up to four hours and when you’re in labour it’s like 16 hours. One of the changes we ask pregnant women to make is small frequent meals to work around that so that they can get the optimal amount of nutrition without carrying that big meal around in their stomach for four hours. Our body fluid increases by 50% and that allows us to accommodate our renal function, our glomerular filtration rate, which is a measurement we use; the amount that’s filtered per minute actually goes up during pregnancy so that we can handle all the additional metabolic work that you’re doing and the baby is doing. So basically it’s a body that’s working way harder than it was just to get through the business of living and those pregnancy changes do help us.