Which of the following parameters are not increased during pregnancy :
RESPIRATORY SYSTEM: With the enlargement of the uterus, specially in the later months, there is elevation of the diaphragm by 4 cm. Total lung capacity is reduced by 5% due to this elevation. Diaphragmatic excursion is increased by 1-2 cm and breathing becomes diaphragmatic. Total pulmonary resistance is reduced due to progesterone effect. The subcostal angle increases from 68deg to 103deg, the transverse diameter of the chest expands by 2 cm and the chest circumference increases by 5-7 cm. The mucosa of the nasopharynx becomes hyperemic and edematous. This may cause nasal stuffiness and rarely epistaxis. Hyperventilation occurs during pregnancy leading to increase in tidal volume and therefore respiratory minute volume by 40%. It is probably due to progesterone acting on the respiratory center and also to increase in sensitivity of the center to carbon dioxide. The woman feels shoness of breath. Reference: Dutta Textbook of Obstetrics 24th edition page 55
Vital capacity
Blood volume
Extracellular fluid
Weight
General obstetrics