Do pregnant women breathe more?

We Posed this question to Dr, Gerald Hackett from The Rosie Maternity Hospital in Cambridge...

Gerald - Good afternoon. I'm Gerry Hackett. I'm a Consultant Obstetrician and Gynaecologist who work at the Rosie. Amongst many other things, I'm a Foetal Medicine Specialist and you've kindly asked me a question about pregnant mums and do they have to breathe more. Certainly, during pregnancy, a mother and a baby need more oxygen. Actually, many people think that the oxygen is just for the baby, but actually, at least half the extra oxygen the mother is taking in is for the placenta. Certainly, also during pregnancy, the mother's basic metabolism just gets higher. During pregnancy, mothers do breathe more. They in fact breathe more deeply. They don't breathe more often, more frequently, just more deeply. And actually, strangely enough, despite taking up extra oxygen in her blood, mothers in pregnancy often feel breathless and that's one of the most common symptoms of pregnancy, is breathlessness strangely enough. So during pregnancy, mothers will feel more breathless that even though they're taking up more oxygen, and letting out more carbon dioxide, they do this in part by movement of the diaphragm. Of course, as the pregnancy gets larger, you'd expect there to be less movement in the diaphragm. But in fact, there's just as much as always and so that tidal volume, the amount of air that a mother will breathe in and breathe out is much the same in pregnancy as outside of pregnancy. The airflow is much the same. The extra oxygen passes through the placenta, is taken up by the placenta, but also by the baby and it transfers quickly over to the baby's side because the haemoglobin - that is the red cells actually in the baby's circulation- picks up oxygen much more easily than our own haemoglobin would do. It binds that oxygen and it releases it into the baby's circulation. Diana - Pregnant women don't breathe more often, but they do breathe more deeply. And surprisingly, the movement their diaphragm can make isn't impeded by the growing baby. And on the forum, CliffordK said their adding 50 pounds to anybody or make it take more energy to walk across the room and oxygen is required to release that energy.