Maternal Adaptations to Pregnancy

Chapter 6: Maternal Adaptations to Pregnancy

1. In-Class Worksheet

  • Focus areas regarding changes during pregnancy include:
    • Integumentary changes
    • Cardiovascular changes
    • Respiratory changes
    • Gastrointestinal (GI) changes
    • Genitourinary (GU) changes
    • Reproductive changes
    • Hormonal changes
    • Musculoskeletal changes
    • Changes in lab values (e.g., Red Blood Cell (RBC) count, Hemoglobin, White Blood Cell (WBC) count, clotting factors)

2. Changes in Body Systems

Integumentary Changes

  • Skin Changes:

    • Hyperpigmentation
    • Chloasma/Melasma (dark patches of skin)
    • Linea nigra (dark line along the abdomen)
    • Vascular changes in the skin

  • Connective Tissue:

    • Striae gravidarum (stretch marks)

  • Hair and Nails:

    • Changes in hair growth and nail strength.
Reproductive Changes

  • Vagina and Vulva:

    • Increased vascularity, resulting in changes in appearance
    • Thickening of vaginal mucosa
    • Prominence of vaginal rugae
    • Increased lactic acid production:
    • Leukorrhea: Increased vaginal discharge
    • Mucous Plug: Formation to protect the uterus

  • Ovaries:

    • Continuous secretion of progesterone is critical
    • Corpus luteum responsible for progesterone production
    • Ovulation ceases throughout pregnancy

  • Breasts:

    • Estrogen stimulates mammary ductal tissue growth
    • Progesterone aids in growth of lobes, lobules, and alveoli
    • Colostrum secreted as early breast milk
    • Darkening of the areola occurs due to hormonal changes

3. Changes in the Cardiovascular System

Blood Volume Changes

  • General Increase in Blood Volume:

    • Increases begin at 6 weeks gestation.

  • Plasma Volume:

    • Elevates from 6 to 8 weeks until 32 weeks gestation.

  • RBC Volume Increase:

    • Increased by approximately 20% to 30%.
    • RBC mass does not see significant increase until 20 weeks.
    • RBC count throughout pregnancy normally ranges from 2.71 - 4.55 million/µL.
    • Concept of Physiologic Anemia of Pregnancy:
    • Dilutional effect due to increase in plasma volume.
Heart Changes
  • Heart Muscles:
    • Increase in myocardium size by 10% to 15% during the first trimester.
    • Changes in heart sounds are common as the heart adapts to increased workload.
Hemodynamics

  • Cardiac Output:

    • Increases by 30% to 50% to meet increased metabolic demands.

  • Systemic Vascular Resistance:

    • Decreases during pregnancy, allowing for greater blood flow.

  • Blood Pressure:

    • Effects of maternal positioning (e.g., supine hypotension syndrome).
Blood Flow Changes
  • Altered Blood Flow Patterns:
    • Importance of uteroplacental unit for fetal development.
    • Renal plasma flow increases up to 30% to support maternal and fetal needs.
    • Increased circulation to the skin and breasts noted.
  • Venous Return Obstruction:
    • Expanding uterus may obstruct venous return from lower extremities, resulting in potential edema.
Additional Hematological Changes
  • Increased iron absorption is necessary to support growing fetal blood volume.
  • Significant increases in clotting factors help prevent hemorrhage during birth.

4. Fundal Height Measurement

  • Measuring Techniques:
    • Using a measuring tape for accuracy from the top of pubic bone to the top of the uterus.
    • Finger method is less accurate.
  • Expected Measurements by Gestation Weeks:
    • At 12 weeks: Fundus is above the symphysis pubis.
    • At 20 weeks: Fundus at the belly button.
    • At 36 to 40 weeks: Fundus descends about 4 cm as the baby engages in the pelvis.
    • Fundal height is typically used to track gestational age within ± 2 cm during pregnancy.

5. Hormonal Changes

  • Estrogen:

    • Stimulates development of uterus and breasts, vascular changes, and may cause hyperpigmentation.

  • Progesterone:

    • Essential for maintaining uterine lining for implantation, decreasing uterine contractions, and promoting breast development for lactation.

6. Respiratory Changes

  • Oxygen Consumption:
    • Increases due to heightened metabolic demands and hormonal effects.
  • Hormonal Influence:
    • Significant effects from progesterone and estrogen causing respiratory tract changes.
  • Physical Changes due to Uterus Growth:
    • Diaphragm elevation and relaxation of ligaments around the ribs facilitates lung expansion but may cause shortness of breath.

7. Gastrointestinal Changes

  • Various impacts from pregnancy on appetite, mouth, esophagus, stomach, and intestines, leading to frequent food aversions and nausea in early pregnancy.

8. Urinary Changes

  • Bladder:

    • Increased frequency noted in 1st and 3rd trimesters due to growing uterus.

  • Kidneys and Ureters:

    • Changes in size, shape, and function of kidneys associated with increased workload and likelihood of urinary tract infections (UTIs).

9. Musculoskeletal Changes

  • Increased fetal demands for calcium lead to adaptive musculoskeletal changes (e.g., diastasis recti).

10. Changes in Lab Values

  • RBC Count: Initially decreases due to hemodilution, then increases during the second half of pregnancy.
  • Normal ranges: 2.75 to 4.55 million/µL.
  • Hemoglobin: Average 9.5 to 15 g/dL, noting a decrease in early pregnancy.
  • WBC Count: Elevates to 5600 - 16,900 per µL during pregnancy.
  • Clotting Factors: Increase from 146,000 - 429,000 per µL.

11. Endocrine Changes

  • Pituitary Gland: Secretion of prolactin and oxytocin.
  • Pancreas: Fluctuations in insulin production and increased insulin resistance.
  • Placenta's Role: Becomes an endocrine organ, secreting hCG, estrogen, progesterone, human placental lactogen, and relaxin.

12. Other Changes

  • Sensory Organs: Changes noted in the eyes and ears.
  • Immune System Changes: Pregnancy induces a state of weakened immunity, affecting susceptibility to infections and managing autoimmune conditions.

13. Confirmation of Pregnancy

  • Presumptive Indicators of pregnancy include:

    • Amenorrhea (absence of menstruation)
    • Nausea and vomiting
    • Fatigue
    • Increased urinary frequency
    • Breast and skin changes, including darkening of areolae and enlarged Montgomery glands
    • Fetal movement (quickening) typically felt between 16-20 weeks

  • Probable Indicators are more certain signs but still not definitive:

    • Abdominal enlargement
    • Softening of the cervix (Goodell’s sign)
    • Bluish discoloration of the cervix (Chadwick’s sign)
    • Changes in uterine consistency (Hegar’s Sign)
    • Braxton Hicks contractions
    • Fetal outline palpation
    • Positive pregnancy tests.

  • Positive Indicators:

    • Auscultation of fetal heart sounds
    • Fetal movements detected by an examiner
    • Visualization of the embryo or fetus via ultrasound.

14. Psychological Adaptations to Pregnancy

  • First Trimester Responses:

    • Uncertainty and ambivalence about pregnancy and motherhood.
    • Focus on self and body changes.

  • Second Trimester Responses:

    • Notable changes in body shape provide physical evidence of pregnancy.
    • Fetus becomes the central focus.
    • Changes in narcissism and introversion as the mother adjusts to bodily changes.

  • Third Trimester Responses:

    • Feelings of vulnerability and dependence increase.
    • Preparation for childbirth and parenting begins, often displayed through nesting behavior.

15. Maternal Role Transition

  • Tasks of Pregnancy:
    • Seeking safe passage (care guidance)
    • Securing acceptance (family/partner support)
    • Learning to give of herself (attachment to the unborn child).

16. Paternal Adaptation

  • Variations in adaptation to pregnancy can include:
    • Realization of the pregnancy and parenthood.
    • Desire for recognition and active engagement in the pregnancy process.
    • Seeking information on parenting responsibilities.

17. Adaptation of Siblings

  • Toddlers: Often unaware of the upcoming baby, need assurance of their importance in the family.
  • Children aged 3-12 years: May understand a sibling is on the way; require reassurance and dedicated support.
  • Older children: Experience personal identity changes and respond to family dynamics shifting with new sibling.

18. Factors Influencing Psychosocial Adaptations

  • Factors include:
    • Absence of a partner
    • Abnormal situations
    • Age considerations
    • Social support networks
    • Multiparity (having more than one child).

19. Signs of Pregnancy

  • Presumptive Changes (maternal feelings):

    • Amenorrhea, nausea, fatigue, increased urinary frequency, breast changes, quickening.

  • Probable Changes (more certain signs):

    • Goodell's sign, Chadwick's sign, Hegar's sign, Braxton Hicks contractions, positive pregnancy test.

  • Positive Indicators (definitive signs):

    • Fetal heart sounds, fetal movements detected by an examiner, visualization of embryo or fetus.