prenatal adaptions to pregnancy pregnancy

Circulatory Changes for the Fetus

  • Discussion on fetal circulatory adaptations:
      - Three major shunts that facilitate fetal blood flow and oxygenation:
        - Ductus venosus: Directs oxygenated blood from the umbilical vein to the inferior vena cava, bypassing the liver.
        - Foramen ovale: Allows blood to flow from the right atrium to the left atrium, avoiding the pulmonary circulation since the fetus does not use its lungs for oxygenation.
        - Ductus arteriosus: Connects the pulmonary artery to the aorta, directing blood away from the lungs.

Changes in the Pregnant Client's Body

  • Overview of physiological and pathophysiological changes during pregnancy.

  • Focus on fetal growth and uterine changes:
      - Uterine Size Increase:
        - Before pregnancy: Approximately the size of a pear.
        - During pregnancy:
          - Fully expanded weight reaches up to 1,200 grams.
          - Capacity of 5,000 mL by term.

  • Fundal Height Measurement:
      - Non-invasive method to assess fetal growth.
      - Fundal height measured at:
        - 16 weeks: Midpoint between pubis and umbilicus.
        - 20 weeks: At umbilicus.
        - Predictable growth pattern: 1 cm per week beyond 20 weeks.
        - Example measurements:
          - 21 weeks gestation: Fundal height should be 21 cm.
          - 30 weeks gestation: Fundal height should be 30 cm.
          - At 36 weeks: Fundus near sternum.

Assessment of Fetal Growth

  • Importance of accurate dating and fundal measurements:
      - Abnormal measurements can indicate:
        - Growth restriction (e.g., if measuring only 26 cm at 30 weeks).
        - Large fetus (e.g., measuring 36 cm at 30 weeks).
          - Possible causes: incorrect dating, gestational diabetes, genetic factors.

Ultrasound and Monitoring

  • Role of ultrasound in prenatal care:
      - Assess amniotic fluid levels.
      - Estimate fetal weight and growth accuracy.
      - Importance of regular prenatal visits for monitoring.
      - Risks of undiagnosed size at labor/birth.

Recognition of Braxton Hicks vs. True Labor Contractions

  • Braxton Hicks contractions:
      - "Practice" contractions, not typically productive and stop with movement.

  • True labor contractions:
      - Become stronger and closer over time. Produce cervical changes including dilation and effacement.

Positioning for Measurements

  • Recommended position for measuring fundal height:
      - Supine position with slight knee flexion is ideal, but must not remain in this position for too long due to risks of supine hypotensive syndrome.

Changes in the Cervix

  • Chadwick's sign: Bluish tint of the cervix due to increased blood flow (hyperemia).

  • Goodell's sign: Softening of the cervix in preparation for labor.

Mucus Plug and its Importance

  • Formation of a mucus plug that protects the cervix and prevents bacteria from entering.

  • Loss of the mucus plug may indicate labor, but does not guarantee admission without contractions.

Respiratory System Changes

  • Increased oxygen consumption results in hyperventilation during pregnancy.

  • Symptoms may include:
      - Nasal congestion due to mucous membrane edema from estrogen.
      - Change in voice due to airway inflammation.

Cardiovascular Changes during Pregnancy

  • Blood volume increases by 45%, with plasma volume rising 40-60%.

  • Increased blood volume is necessary for:
      - Supporting uteroplacental circulation and preparing for blood loss during delivery.

  • Increased cardiac output, best assessed in the left lateral position for optimal venous return.

Increased Risk Factors

  • Pregnant patients may develop physiological anemia due to plasma dilution.

  • Increased risk of blood clots due to a hypercoagulable state.

Gastrointestinal Changes

  • Increased blood supply leads to:
      - Gum bleeding and gingivitis due to high estrogen levels.

  • Decreased esophageal tone can cause heartburn.

  • Constipation resulting from slowed GI motility, exacerbating hemorrhoid issues.

Liver, Gallbladder, and Cholestasis

  • Increased risk for gallstones due to prolonged emptying time of the gallbladder.

  • Cholestasis of pregnancy:
      - Symptoms include itching, particularly in hands, due to accumulation of bile salts.
      - Management may involve medication and potential early delivery to prevent fetal complications.

Conclusion & Reminder

  • Importance of regular prenatal appointments for monitoring maternal and fetal health, and understanding physiological changes during pregnancy.