Reference:
- Dr. RPS Maternal and Newborn Care: A Comprehensive Guide and Source Book for Teaching and Learning, 2nd Edition, ISBN 9789719822653, by Rosalinda Parado Salustiano (Ch. 5, pp. 80–116)
Reproductive System
The Uterus grows from 7.5 × 4 × 2.5 cm, pyriform/pear-shaped to 32 × 24 × 22 cm, globular/oval. Its weight increases from 60 ~ 70 grams to 1,000 grams. Despite this, no new uterine muscle is formed. The existing muscle fibers become hypertrophic, and new fibroelastic tissues form to make stronger uterine walls. Changes are progressive.
- 12 weeks: the corpus and fundus become globular; almost spherical.
- Fundal Height is at the level of the symphysis pubis until the 12th week, and is generally only palpable by the 13th week just above the symphysis pubis. It reaches the umbilicus by the 20th to 22nd week, and the xiphoid process by the early 36th week. This is also expressed in Bartholomew’s Rule.
- Increased vascularity (because of Estrogen) results in three probable signs of pregnancy:
- Hegar’s Sign: softening of the isthmus.
- Goodell’s Sign: softening of the cervix
- Chadwick’s Sign: blue/purple discoloration of the cervix and vaginal mucosa. This may also be seen as a presumptive sign of labor as observed by the pregnant woman.
- Braxton Hicks Contractions: intermittent, irregular, painless, abdominal, and false labor contractions felt by 4 months, and is more pronounced on the 8th month.
- Ballottement: rebounding of the fetal head against examining fingers by 4 to 5 months (16th to 18th week of gestation). This is felt by healthcare examiners on the third Leopold’s Maneuver (Pawlick’s Maneuver).
- Secondary Amenorrhea: often the first sign that alerts a woman to pregnancy; the lengthened lifespan of the corpus luteum (from two weeks to two months) prevents another menstrual period to initiate.
- Uterine Electrical Activity: low and uncoordinated in early gestation, progressively intensifying and synchronizing at term. This synchronization occurs twice as fast in multiparas.
The cervix becomes shorter, thicker, and more elastic. Its mucosal lining increases mucus production (from edema and thickening), which creates the mucus plug by week 7 that protects the uterus from bacterial contamination. As previously mentioned, this is also subject to Chadwick’s Sign, becoming discolored to blue/purple from increased vascularity. The vagina also becomes thicker and hypertrophic, thickening the vaginal mucosa. Leukorrhea occurs as whitish, mucoid, non-foul, non-pruritic vaginal secretions increase along with estrogen. Vaginal acidity increases, adding protection against bacterial invasion.
Ovulation and maturation cease as the ovaries’ function is overtaken by the corpus luteum in early pregnancy; it functions maximally during the first 6 to 7 months of pregnancy.
The perineum becomes hypertrophic, experiences edema, and relaxation. It also becomes a deeper color due to vascularization. The breasts increase in size and firmness. The areola and surrounding skin darkens and enlarges, along with the alveoli system, alveoli duct, and Montgomery’s glands. Superficial veins enlarge and become prominent. Breastfeeding can be done as early as 4 to 5 months (for other infants, if needed), as colostrum begins to be produced.
Endocrine System
The major endocrine organ during pregnancy is the placenta. Its chorion (15 to 20) secrete Human Chorionic Gonadotropins (hCG) which (a) maintain the corpus luteum by secreting progesterone in early pregnancy, its most important function, and (b) aids in diagnosing pregnancy, as it is detectable in serum (by 8 to 10 days after implantation) and urine (by 10 to 14 days after first missed menstruation). hCG is found to be elevated in pregnant women experiencing vomiting.
- The placenta matures by 10 to 12 weeks (3 months), increasing placental hormones estrogen, progesterone, hCG, and hPL/hCS (Human Placental Lactogen/Human Chorionic Somatomammotropin).
hPL is the major diabetogenic hormone in pregnancy, contributing to gestational DM.
The anterior pituitary gland becomes ready for breastfeeding through increase prolactin. FSH production from the APG does not result in ovulation. The posterior pituitary gland (PPG) secretes oxytocin from the hypothalamus when fetal head pressure on the cervix increases. Oxytocin acts to stimulate the uterine myometrium, causing uterine contractions and labor onset, especially with the decrease in progesterone, which inhibit contractions, in late pregnancy.
Thyroid changes result in increased basal metabolic rate (BMR), only returning to normal levels 6 weeks postpartum. This is due to elevated serum estrogen, placental effects, and renal clearance of iodide. Increased BMP is manifested by increased pulse rate and cardiac output, a slight rise in temperature, and heat intolerance. The Parathyroid glands enhance calcium and phosphorus metabolism to meet fetal needs of calcium. If calcium needs are not met, maternal cramping occur from calcium-phosphorus imbalance.
- The pancreas increase insulin production in response to increased metabolism.
Finally, the adrenal cortex increase cortisol production to promote metabolism and activate gluconeogenesis (protein to glucose) when energy is required, and aldosterone for sodium retention (and therefore water reabsorption), resulting in the cushingoid features of pregnancy
Respiratory Systems
The lungs have a slight increase in vital capacity. Oxygen consumption increases by 15% from 6 to 40 weeks of pregnancy. The fetus consumes oxygen and contributes carbon dioxide, demanding increased oxygen and increased excretion of carbon dioxide. This creates a tendency to hyperventilate, resulting in dizziness, lightheadedness, pallor, and tingling sensation on fingertips/lips.
- Resolve hyperventilation and avoid respiratory alkalosis by promoting re-breathing with a paper bag or cupped hands.
The gravid woman experiences increased vascularity (from estrogen) of the nose, contributing to common epistaxis, nasal stuffiness, hoarseness, eustachian tube blockage (potential temporary deafness). Respiratory rate does not vary largely, reaching a maximum of 24 respirations per minute while at rest (normally 20). Lung volume may decrease based on mechanical, hormonal, or biochemical influences.
The diaphragm rises by as much as one inch at the final month of pregnancy (week 36 to 38), resulting shortness of breath or dyspnea. This discomfort of pregnancy is relieved after lightening, the descent of the fetal presenting part into the pelvic inlet.
Circulatory System
Cardiac rate increases by 10 to 15 BPM in the second and third trimesters. Blood pressure remains constant by may drop slight in the second trimester. Disturbance of blood pressure is primarily due to vena caval syndrome/supine hypotensive syndrome, where the inferior vena cava becomes compression when laying in a supine position, decreasing cardiac output and producing hypotension. This is managed by remaining in a left lateral recumbent position.
- Palpitations may occur due to sympathetic nervous system disturbances (early pregnancy) or increased intraabdominal pressure (late pregnancy). Transient murmurs (increased blood viscosity and displacement of the heart) and slight cardiomegaly also occur.
- Increased tissue demands and water retention increase cardiac output by 20% to 30%, and blood volume by 30% to 50%. Physiologic anemia may occur, where red blood cells are not proportionate with the blood volume.
- As previously mentioned, estrogen levels increase vascularity, producing Hegar’s, Goodell’s, and Chadwick’s signs. Pelvic veins become distended and leg varicosities appear.
- Fibrinogen increases by 50% due to progesterone, which increases risk for thromboembolism, e.g. DVT. Monitor for DVT with Homan’s sign.
| Parameter | Value in Pregnancy |
|---|---|
| Red Blood Cells | Increased by 30%, but often drops in the second and third trimesters. |
| Hemoglobin | 12 to 15 g/dL |
| Hematocrit | 37% to 42% in pregnancy. This may drop by 10% in the second and third trimesters from pseudoanemia/physiologic anemia. |
| White Blood Cells | Elevated to 5,500 to 11,500/mm3 in pregnancy, 20,000/mm3 in labor, and 25,000/mm3 postpartum. These findings are normal; leukocytosis is not usually a sign of infection. |
Gastrointestinal System
- Mouth: increased estrogen; increased saliva acidity, salivation in women with nausea (ptyalism) disappearing after delivery, increased vascularity (soft and swollen gums, difficulty chewing, bleeding), and potential benign mouth tumors from vascular proliferation.
- Stomach: displaced backwards, with bowel sounds potentially unheard in all quadrants. Difficult digestion results from pressure/compression by the gravid uterus, resulting in pyrosis (heartburn), a discomfort of pregnancy. Motility, digestion, and emptying time are all slowed due to progesterone. This also contributes to morning sickness, another discomfort of pregnancy.
- Gastrointestinal Tract Relaxation: as an effect of progesterone; contributes to morning sickness, flatulence, constipation, and hemorrhoids as discomforts of pregnancy.
- Gall Bladder: another organ relaxed by progesterone, delaying emptying time. Prolonged storage predisposes the cholesterol to crystallize, forming a gallstone.
- Liver: displaced, but blood flow is not affected. Laboratory findings may mimic liver disease, as albumin is decreased by 30%, serum alkaline phosphatase is increased by two to three times, and cholesterol is double the nonpregnant level (normally 150 to 200 mg/dL).
- Urinary System: urinary frequency is present in the first and third trimesters, when the uterus places pressure on the bladder. In the second trimester, as the uterus rises to the abdominal cavity, the uterus undergoes retroversion. Renal function is also compromised by the vena caval syndrome. Management is the same.
- Renal plasma flow* is increased by 25% to 50%. It is normal by the end of the third trimester.
- Glomerular* filtration rate (GFR) is increased by 50% in the second and third trimester. This increases urinary output with decreased specific gravity.
- Increased renal tubular reabsorption rate, urea clearance, and creatinine clearance.
- Bladder capacity is 1,500 mL in the second trimester.
- Glycosuria occurs as glucose threshold decreases.
- The smooth muscles of the bladder and ureters relax, persisting for up to 4/6 weeks after delivery and results in ureter dilation, decreased bladder tone, and increased potential for stasis and UTI.
Integumentary System
Starting from the second trimester onwards, various marks may appear:
- Chloasma: dark patches on the cheeks, nose, and neck; the “mask of pregnancy” due to increased melanocyte-stimulating hormones of pregnancy.
- Linea Nigra: a dark line from the symphysis pubis upward to the xiphoid process due to increased estrogen.
- Striae Gravidarum: stretch marks; silvery streaks on the abdomen, upper thighs, and lower breasts due to adrenal hypertrophy.
- Palmar Erythema: redness of the palms from vascularization by estrogen.
- Vascular Spider Nevi: redness of the face from vascularization by estrogen.
- Diaphoresis: resulting from increased BMR (from thyroid gland changes).
Musculoskeletal Changes
Increased estrogen, progesterone, and relaxin relaxes ligaments and joints; softening and relaxation of the symphysis pubis and sacroiliac joints (increased size of the birth canal), pelvic looseness (resulting in a waddling gait), and difficulty in maintaining balance.
- Due to impaired balance, bathing in tubs is not suggested.
The added stress on the ligaments and muscles of the mid- and lower spine results in backache. This is further contributed to by lordosis as the center of gravity shifts forward during pregnancy.
Fetal bone ossification on the seventh month depleted calcium, predisposing the mother to leg cramps from calcium-phosphorus imbalance. the pressure of the gravid uterus on the nerves supplying the lower extremities also contribute.
Psychosocial Changes
| First Trimester | Second Trimester | Third Trimester |
|---|---|---|
| Denial | Acceptance | |
| Ambivalence; Emotional Lability | Fantasizing/Day-dreaming | Fear, anxiety, dreams of labor, pain, mutilation, and death |
| Focusing on the self | Introspective, evaluating marriage, career, and in-laws | Preparing for birth; nesting behavior, role-playing |
| Task: acceptance of pregnancy | Task: preparation for physical separation | Task: attainment of maternal role |
The nurse must understand these psychosocial adaptations and implement them into care:
- Encourage the pregnant woman to verbalize and express her feelings, concerns, and discomforts. Encourage her to ask questions.
- Validate the normalcy of women’s feelings and reactions in order to provide psychological support.
- Improve level of maternal comfort. Provide health teachings related to the prevention and management of common discomforts of pregnancy and the daily hygiene of pregnancy.
- Recommend attendance in prenatal classes in the third trimester.
Seven Dimensions of Maternal Development (Lederma & Weis)
- Acceptance of the pregnancy
- Motivation and preparation for motherhood
- Relationship with husband/partner
- Relationship with her own mother
- Preparation for labor
- Sense of control in labor
- Self-esteem and well-being in labor