Hi, Thanks for the query. I understand your concern. In pregnancy there is rise in blood volume ( for fetal circulation ).. this is by dilution of blood, so the hemoglobin percentage ( the oxygen carrying substance ) gets reduced. Also respiration become difficult due to decreased due to pregnancy hormones ,while oxygen demand is increased by 20% in pregnancy. All these factors together cause compensatory rise in respiratory rate & heart rate.. in an attempt to provide necessary oxygen to growing fetus. The thing can be managed by- - Rise in Hb% ( treatment/ consumption of healthy diet with proteins, iron, vitamins ) - Learning to increase respiratory capacity by using thoracic breathing ( pregnancy special Prnayama) thanks.