Pregnancy is marked by several physiological changes and this is no surprise. But, many of these changes can be new for the mothers which can worry them about the fetal development. Thereby, it is important for you to know about the core physiological changes in the mother which are just a part of normal pregnancy. These changes include:
- Changes In The Cardiovascular System
- Cardiac output increases, resistance to blood flow and blood pressure reduce during pregnancy.
- Volume of blood plasma and amount of red blood cells increase by 4th week of gestation.
- During pregnancy it is normal to experience increased cardiac output (amount of blood pumped out per minute), reduced systemic vascular resistance (to help maintain a blood flow) and reduced systemic blood pressure.
- Increased water and sodium retention in the blood can also lead to the expansion in blood volume during the course of pregnancy.
- The amount of red blood cells and volume of blood plasma begin to take place in the 4th week of pregnancy and a peak is reached between 28th and 34th At this time, the maternal blood circulation requires to maintain equilibrium between water molecules and sodium ions, which leads to 6-8 liters of water retention in the body and sodium retention equivalent to 900-1,000 mEq, respectively.
- By the time, a pregnancy reaches to term, the final plasma volume is 30%-50% more than a non-pregnant woman, ranging between 4700 mL and 5200 mL.
- Changes In The Respiratory Tract
- The dimensions of the diaphragm and thorax change to facilitate the increased demand of oxygen.
- To meet these increased oxygen demands, the pulmonary ventilation is increased by 30% to 40%
- The onset of pregnancy is marked with the changes in the diaphragm and thorax due to the increased demands of the maternal body.
- In the first trimester, the lower opening of the rib cage increases from (subcostal granuloma) 680 to 1030. Simultaneously, the diaphragm rises by 4 cm and the chest diameter is increased by 2 cm or more.
- As the pregnancy proceeds, FRC (volume of air present in lungs present after normal expiration) is reduced from 1.7 L to 1.35 L which leads to the lung capacity reduction by 5%. The ERV(expiratory reserve volume) is reduced and the tidal volume is increased at this time.
- The oxygen requirement increases to50mL/min, out of which 20mL/min is used by the reproductive tissues. To meet this increased oxygen requirement, the pulmonary ventilation is increased by 30% to 40% as compared to a non-pregnant state.
Renal Physiology Of Pregnancy: Changes In Kidneys During Pregnancy
- During pregnancy the blood flowing to the kidney and the filtration rate are significantly increased.
- The waste products to be excreted out of the renal system are also increased in quantities.
- By the time a pregnancy reaches 16th week of gestation, the blood flow in the kidneys is increased by 80% and similarly the rate of glomerular filtration rate is increased by 55%.
- During this time, as the kidneys need to filter increased amounts of waste products out of the body, the kidneys swell up and the become 1 cm longer.
- The levels of proteins excreted out of the body, condition termed as proteinuria, is also increased in pregnancy as compared with the normal urinary protein excretion levels which are upto 150 mg/24 hours.
- However, if the levels exceed the value of 300 mg/24 hours, then it is your time to worry and seek assistance from your doctor.
- At the same time, you are likely to experience gestational glycosuria, which is characterized by excessive sugar excreted in the urine. This condition results from reduced tubular glucose reabsorption in the kidney and normally does not mean that your carbohydrate metabolism is disrupted.
- Changes In Liver Metabolism
- Blood flowing to the liver and the size of liver are not changed in pregnancy, but the liver metabolism is significantly changed.
It is important to know that despite being overworked during pregnancy, the blood flow through the liver and the size of liver do not change. However, gestation is marked by altered function and metabolism which show distinction changes in the levels of serum proteins.
- At this stage, the concentrations of certain proteins in the serum are increased which include ceruloplasmin, fibrinogen, transferrin and thyroid-binding globulin.
- On the other hand, the serum albumin levels are increased by 25%. By the time, your pregnancy reaches its completion the serum cholesterol level and triglycerides level are increased by 50% and 300% respectively.
- Changes In Skin
During pregnancy many physiological changes take place in the body to prepare the mother to nurture the baby in her womb and later breastfeed the child after birth.
- Several skin conditions, pigmentation, stretch marks and vein enlargement are common during pregnancy.
- These conditions normally go away soon after pregnancy.
- These include breast enlargement, increase in the size of the belly, swelling of legs and feet, pigmentation of pregnancy called as chloasma gravidarum.
- These changes usually subside gradually after delivery as the placental hormones cease to cause an effect to the body after the end of pregnancy.
- Chloasma gravidarum usually resolves after delivery in a few months due to scarcity of the affecting hormones.
- But in some cases it can persist in a woman throughout her lifespan. It is called as the mask of pregnancy which affects the cheeks, neck, upper arms and other body parts.
- A line of pigmentation from the belly button to the pubic bone is called linea nigra or the pregnancy line. It is also caused by the hormonal changes in pregnancy and resolves with the shedding of the placenta in a few months usually.
- Many women also experience stretch marks on their body, particularly on the belly region. Numerous lotions and creams have been proven beneficial and claim to settle the issue.
Changes In Nails And Hair During Pregnancy
Due to the surge of hormones in pregnancy, your nails and hair are likely to go through a variety of changes.
- Nails begin to grow fast but become brittle during pregnancy. The hair growth is significantly increased during this time as well.
- While during this time, you might notice that your nails are growing faster than before, you will also find them to be increasingly brittle.
- Similarly, during pregnancy your hair growth is likely to improve as the ovarian androgens and corticosteroids levels increase during this time and the hair growth cycle enters the growing phase known as anagen.
- However, as the hormones go back to their normal levels during the postpartum period, the increased hair growth in reversed and resting phase (telogen) is reached.