A lot of normal changes during pregnancy occur. A pregnant mother may expect changes in their body as the baby grows inside of her for nine months. But for first time mothers, these changes may definitely surprise them and sometimes can cause panic to the starting family. One must then remember the following normal physiologic alterations in a pregnant woman:
Changes in the Reproductive System
The uterus will start to undergo enlargement and thickening, also known as uterine hypertrophy. The superior part of the uterus, or the fundus, is the most remarkable area. The fundus will be then palpable at the level of the umbilicus by 4 ½ months (20th week of age of gestation, AOG). At the 36th week, the fundus can be palpated at the level of the xiphoid, lowest vertical border of the sternum. It will then descend slightly during the last 3 weeks because of gradual fetal descent into the pelvis.
The cervix will have a pronounced softening and bluish discoloration due to the increased vascularity, swelling and hypertrophy of the cervical glands. It is known as the Goodell’s sign. A cervical plug will also be formed by the thick mucus clotting at the cervical opening.
Ovulation will then stop throughout pregnancy, as hormonal regulation suppresses this function of the ovaries.
In the vagina, there is increased vascularity too followed by softening of the perineum and vulva. This results to the cyanotic appearance of the vaginal wall, also known as Chadwick’s sign. The vaginal mucosa will have an increase in thickness with the connective tissues loosening and the muscle cells in this area will enlarge. There is an expected increase in vaginal secretions with pH of 3.5-6 due to the increased production of lactic acid from the normal presence of doderlein bacillus in this part of the body.
In addition, the mother will experience breast tenderness and tingling during the early weeks of the pregnancy. The nipples will increase in size and pigmentation. By the start of the 2nd semester, colostrums is expected to flow out. At the same time, there is elevation of Montgomery glands or hypertrophic sebaceous glands.
Changes in the Integumentary System
Changes in the Metabolic System
An average weight gain of 24 to 28 lbs (11-13 kg) is expected. The breakdown of the weight gain is as follows: fetus (3400 grams); maternal stocks (1800-3600 grams); additional blood (1700 grams); breast tissue (1400 grams); amniotic fluid (1000 gram); placenta (500 gram); uterus (1 gram). The expected weight gain should be consistent, ideally speaking. During the 1st trimester, 2-4 lbs is expected. By the end of 2nd trimester, 12-14 lbs should be added. And at the end of the last trimester, 8-12 lbs is gained.
The average pregnant woman will keep 6-7 liters of extra water throughout pregnancy. There will be increased protein metabolism due to the increased necessities of the fetus, uterus and maternal blood.
The normal action of insulin will be inhibited during pregnancy due to the release of hormones by the placenta: human placental lactogen, estrogen, progesterone and added insulin. Based on studies, pregnancy has the potential to increase diabetic chances and can aggravate the present status of a diabetic pregnant mother. It is during pregnancy that there is glucose sparing as it is utilized by maternal tissues and glucose shunting for fetal use via the placenta.
In fat metabolism, fats are more totally absorbed by a pregnant woman’s body. This makes plasma lipid levels increase especially during the latter half of pregnancy. As expected also, iron requirements increase to 20-40 mg daily. By the latter half again of pregnancy, iron is delivered to the fetus and stored in the fetal liver for future use.
Changes in the Endocrine System
The placenta is busy producing hormones such as estrogen, progesterone, human chorionic gonadotropin and human placental lactogen. With the higher levels of estrogen and progesterone, the pituitary gland will suppress productions of luteinizing hormone, follicle stimulating hormone and oxytocin.
Changes in the Cardiovascular System
The heart will be displaced upwards by the elevation of the diaphragm. A notable clinical finding, normal in pregnancy, is a common splitting of the first heart sound, with usual systolic murmurs.
The cardiac volume will increase, by about 40-50% which results to a slight heart hypertrophy and elevation of cardiac output, to which also increases when the pregnant woman lies on her back facing the left side. There is expected anemia to some pregnant women. The pulse rate increases by 10-15 beats per minute. A slight decrease in BP is also expected during the last 2 trimesters.
The total circulating red blood cells will expectedly increase with leukocyte count elevation during the labor phase. On the other hand, fibrinogen and other clotting factors increase by about 50%.
Changes in the Respiratory System
Sometimes, one may notice that a pregnant woman often performs hyperventilation. It is due to the increased respiratory rate and tidal volume. Even after taking arterial blood gas studies, mild respiratory alkalosis will be expected due to a bodily compensatory process to lowered amounts of bicarbonate in the blood.
The enlargement of the uterus causes the elevation of the diaphragm. At the same time, the thoracic cage expands through flaring of the ribs resulting to an increase mobility of rib accessories.
Changes in the Urinary System
The ureters of a pregnant woman become dilated and elongated due to pressure upon growth of the fetus. Glomerular filtration rate in the kidneys also increase. Glucose may be detected in the urine because of heightened renal threshold of glucose. But it is already alarming when traces of protein are present since it signifies a hypertensive pregnancy disorder or other renal disorders.
“Procreation is a gift from the divine and child bearing is a miracle.”