Adaptation of physiology in pregnancy
During gestation, the pregnant mother undergoes important anatomical and physiological changes to nurture and accommodate the developing fetus. These changes begin with conception and have an effect on each organ system within the body. Women experiencing Associate in Nursing uncomplicated gestation, these changes resolve when gestation with marginal residual effects. It is necessary to know the conventional physiological changes occurring in gestation as this can facilitate differentiate from variations that square measure abnormal.
In pregnant women, physiological changes occur not only related to changes in shape and weight, but also in biochemical, physiological, and even emotional changes. As the fetus grows and pushes the diaphragm upward, the shape and size of the chest cavity changes even it does not make it smaller. The lung capacity for air remains the same as before. Further, respiratory speed and vital capacity do not change.
Tidal volume, ventilator volume, and oxygen uptake increase during the pregnancy since the shape of the thoracic cavity changes. As a result, it breathes faster. During pregnancy, hormonal changes and mechanical factors also occur. These changes are needed to sufficiently increase metabolic and circulating needs for the growth of the fetus, placenta, and uterus. From mechanical factors, there is an increase in the diaphragm, especially after the second trimester of pregnancy due to an enlarged fetus. This causes a decrease in functional residual capacity (a volume of air that is not used in the lungs of about 20%). During normal pregnancy, there is a decrease in airway resistance by 50%.
These changes cause changes in blood chemistry and gas. Due to increased ventilation, there is a decrease in pCO2 to 30 mmHg, fixed pO2ranges from 90 – 106 mmHg. The decrease in pCO2 will take a secondary mechanism of the kidney to reduce plasma bicarbonate to 18-22 mEq / l. This change causing the blood pH does not change. Anatomically there is an increase in subcostal angle from 68.5 – 103.5 during pregnancy. This physical change is caused by the elevation of the diaphragm by about 4 cm and the increase in chest transverse diameter to a maximum of 2 cm.
Here are we have submitted some changes that occur in each trimester:
Maternal oxygen demand increases in response to accelerated metabolic rate and increased oxygen demand in uterine and breast tissue. The fetus needs oxygen and a way to get rid of carbon dioxide. Increased oxygen levels cause the ligament in the rib cage to relax. This is done to make sure the expansion of the chest cavity increases. Pregnant women breathe deeper but the frequency of breathing only slightly increases. The increased respiratory tidal volume associated with normal breathing frequency causes an increase in one-minute breath volume of about 26%.
An increase in breath volume of one minute causes the carbon dioxide concentration of the dialveoli to decrease. Besides, in pregnancy, there is also a change in the respiratory system to be able to fulfill oxygen needs. Besides, there is a diaphragm pressure because the uterine urge enlarges at 32 weeks’ gestation. This is found as compensation for uterine pressure and increased oxygen demand. Awareness of taking a deep breath increases in early pregnancy. That might be interpreted as dyspnoea. It often suggests that there is a lung disorder, even though it’s in good condition. Increased breathing effort during pregnancy is likely to be induced mainly by progesterone and estrogen. The increased breathing effort results in pCO2 or reduced carbon dioxide pressure.
During pregnancy, the thoracic srikumferensia will increase by about 6 cm. Also, the diaphragm will rise to around 4 cm due to suppression of the uterus in the abdominal cavity. In advanced pregnancy, tidal volume, ventilation volume per minute and oxygen uptake per minute will increase significantly. Due to a decrease in oxygen pressure, a pregnant woman often feels and complains of shortness of breath and thus increases breathing effort.
The movement of the diaphragm is increasingly limited as the size of the uterus increases in the abdominal cavity. Pregnant women will breathe deeper so that gas mixing can increase and oxygen consumption increases by 20%. At 32 weeks and more, the intestines depressed the uterus is enlarged towards the diaphragm. So, the diaphragm is less mobile to move resulting in difficulty in breathing for pregnant women.
Pregnant gymnastics is an exercise for pregnant women aimed to strengthen leg muscles, considering that the legs will support the growing body weight along with increasing gestational age. Preventing varicose veins’, widening the veins (veins) segmentally which is not uncommon in pregnant women. Extend the breath will push the stomach toward the chest. This will make the chest cavity narrower and the mother’s breath cannot be optimal. With doing pregnancy exercise, the mother will be invited to practice. This thing is done for her breath getting longer and relaxes.
Types of breathing patterns:
- Eupnea. Rhythm and normal respiratory rate
- Takipneu. Increased respiratory rate
- Bradypnea. Slow but normal breathing
- Apnea. There is no breathing
- Chene Stokes. Breathing gradually faster and deeper, and then slowing down between periods of apnea.
- Biots. Fast breathing and deep stop suddenly
- Kussmaul. Fast and deep breathing without stopping
Going the 5th month of pregnancy, expiratory reserves more volume, and residual volume. Later, functional residual capacity decreases. Then, nearing the end of pregnancy decreases by 20% compared to non-pregnant women. In general, there was an increase in the inspiratory reserve volume so that total lung capacity did not change. In some pregnant women, a decrease in functional residual capacity does not cause problems. For those who experience a change in the closing volume earlier, such as a result of smoking, obesity, or scoliosis, can experience initial airway obstructions with advanced pregnancy that causes hypoxemia. The Trendelenburg maneuver and supin position can also reduce the abnormal relationship between closing volume and functional residual capacity. Residual volume and functional residual capacity return to normal condition after labor.