not significantly different than that of non-pregnant women. this alludes to some sort of stability mechanism that allow pregnant women to compensate for the changes they experience during pregnancy. gait gait in pregnant women often appear as a “waddle” – a forward gait that includes a lateral component. however, research has shown that the forward gait alone remains unchanged during pregnancy. it has been found that gait parameters such as gait kinematics, (velocity, stride length, and cadence) remain unchanged during the third trimester of pregnancy and 1 year after delivery. these parameters suggest that there is no change in forward movement. there is, though, a significant increase in kinetic gait parameters, which may be used to explain how gait motion remains relatively unchanged despite increase in body mass, width and changes in mass distribution about the waist during pregnancy. these kinetic gait parameters suggest an increased use of hip abductor, hip extensor, and ankle plantar flexor muscle groups. to compensate for these gait deviations, pregnant women often make adaptations that can result in musculoskeletal injuries. while the idea of "waddling" cannot be dispensed, these results suggest that exercise and conditioning may help relieve these injuries. respiratory there are many physiologic changes that occur during pregnancy that influence respiratory status and function. progesterone has noticeable effects on respiratory physiology, increasing minute volume (the amount of air breathed in and out of the lungs in 1 minute) by 40% in the first trimester via an increase in tidal volume alone, as the respiratory rate does not change during pregnancy. as a result, carbon dioxide levels in the blood decrease and the ph of the blood becomes more alkaline (i.e. the ph is higher and more basic). this causes the maternal kidneys to excrete bicarbonate to compensate for this change in ph. the combined effect of the decreased serum concentrations of both carbon dioxide and bicarbonate leads to a slight overall increase in blood ph (to 7.44 compared to 7.40 in the non-pregnant state) . if an arterial blood gas (abg) specimen is drawn on a pregnant woman, it would therefore reveal respiratory alkalosis (from the decrease in serum carbon dioxide mediated by the lungs) with a compensatory metabolic acidosis (from the decrease in serum bicarbonate mediated by the kidneys). as the uterus and fetus continue to enlarge over time, the diaphragm progressively becomes more upwardly displaced. this causes less space to be available for lung expansion in the chest cavity, and leads to a decrease in expiratory reserve volume and residual volume. this culminates in a 20% decrease in functional residual capacity (frc) during the course of the pregnancy. oxygen consumption increases by 20% to 40% during pregnancy, as the oxygen demand of the growing fetus, placenta, and increased metabolic activity of the maternal organs all increase the pregnant woman's overall oxygen requirements. this increase in oxygen consumption paired with the decrease in frc can potentially mean that pregnant people with pre-existing and/or comorbid asthma, pneumonia, or other respiratory issues may be more prone to disease exacerbation and respiratory decompensation during pregnancy.