Fetal Wellbeing and Healthy Pregnancy Study Notes

Fetal Wellbeing and Healthy Pregnancy Nursing 201 Study Notes

Objectives of the Course

  • Apply the concepts of health promotion and primary prevention in the care of healthy childbearing families.

  • Use standards of care that enhance health for the pregnant client and establish family-centered care.

  • Implement standards of care for promoting and maintaining fetal well-being.

  • Apply principle-based teaching in evidence-based health promotion interventions related to prenatal health.

Fetal Development

Stages of Fetal Development

  • A fertilized egg matures from a single cell to a fully developed fetus ready for birth in approximately 38 weeks.

  • Different cultures and religions vary on when life begins, but fetal growth and development are typically divided into three main periods:

    • Pre-embryonic Phase: First 2 weeks post-fertilization.

    • Embryonic Phase: Weeks 3 through 8.

    • Fetal Phase: From week 8 through birth.

Terms Used to Describe Fetal Growth

  • Ovum: From ovulation to fertilization.

  • Zygote: From fertilization to implantation.

  • Embryo: From implantation to 5-8 weeks.

  • Fetus: From 5-8 weeks until term.

  • Conceptus: Refers to the developing embryo and placental structures throughout the pregnancy.

  • Age of Viability: The earliest age at which a fetus can survive if born, generally accepted as 24 weeks or at a weight of over 500-600 g.

Cycle of Fertilization

  • Follicle with maturing egg (ovum) goes through:

    • Ovum: Ovulation → Fertilization occurs in the outer third of the fallopian tube.

    • Zygote: Fertilization → Implantation (Days 0-8).

    • Embryo: Implantation → 5-8 weeks.

    • Fetus: ~8 weeks → Term (38-40 weeks).

Placenta Function

  • Serves as the fetal lungs, kidneys, and digestive tract while in utero. Key developments include:

    • By 12 days of pregnancy: Maternal blood collects in the intervillous spaces of the endometrium.

    • By 3rd week: Oxygen and nutrients osmose from maternal blood through the chorionic villi, nourishing the developing fetus.

Fetal Growth and Development Milestones

  • Key Points of Development at Various Weeks:

    • Weeks 2-6: Development of central nervous system, heart, upper limbs, eyes, lower limbs, palate, ears, teeth, and external genitalia.

    • Critical periods of fetal growth identified.

Naegele’s Rule to Calculate Due Date

  • Determine the due date using the woman's last menstrual period (LMP):

    • Steps:

    1. Start with the first day of the last menstrual period.

    2. Count back 3 months.

    3. Add 7 days.

    4. Add one year if necessary.

    • Example: If LMP is August 7, 2022, you calculate the due date accordingly.

Assessing Fetal Health and Wellbeing

  • Important parameters for assessing fetal well-being include:

    • Fetal growth through measurement of fundal height using McDonald's rule.

    • Monitoring fetal heart rate and fetal movement.

    • Using kick counts to assess fetal activity.

    • Rhythm strips and non-stress tests to examine fetal heart rate variability.

    • Ultrasound to visualize the developing fetus.

Fundal Height Measurement

  • Definition: The distance from the top of the pubic bone to the top of the uterus, helping to assess fetal growth and gestational age.

  • Measuring Techniques:

    • Using a measuring tape for accurate distance.

    • Finger method prone to errors.

  • Interpreting Fundal Height:

    • Measurement variations of 2 cm or more from expected could indicate:

    • Incorrect due date

    • Slow or rapid fetal growth

    • Abnormal amniotic fluid levels

    • Poor maternal nutrition

    • Molar pregnancy

    • Multiple gestation.

Fetal Heart Rate Monitoring

  • Fetal heart tones (FHT) are typically detectable via an Ultrasonic Doppler around 10-12 weeks of gestation.

  • Normal fetal heart rate ranges between 110-160 beats/min.

    • Procedure:

    1. Patient lies on back.

    2. Heart rate checked for 1 minute.

    3. Instruct on what constitutes a normal rate.

Fetal Movement Counts (FMC)

  • Quickening is typically felt between 15-18 weeks.

  • By 28 weeks, patients are instructed to monitor fetal movements, using the following guidelines:

    • Count daily movements noting the time and position (left side recommended).

    • Count until 10 movements are felt, recording the time taken.

    • Contact healthcare provider if movement is less than expected over a period of 2 hours.

Advanced Fetal Monitoring Techniques

Rhythm Strip Testing

  • Assesses fetal heart rate using an external fetal heart rate monitor over at least 20 minutes during labor, looking for 2 or more episodes of fetal heart rate increases.

Nonstress Testing

  • Measures fetal heart rate's response to movement, with the following procedure:

    • Position mother in low Fowler's position.

    • Attach transducers for about 20 minutes.

    • The mother presses a button each time she feels movement.

    • Ideal response: Fetal heart rate increases by 15 beats upon movement.

  • Reactive Nonstress Test: At least 2 accelerations lasting 15 seconds occur post-movement.

  • Nonreactive Nonstress Test: No accelerations or <= 6 beats/min with movement.

Ultrasound Examination in Pregnancy

  • Ultrasound employs high-frequency sound waves to project visuals of the uterus.

  • Uses include:

    • Early pregnancy assessments.

    • Mid and late pregnancy evaluations.

Amniotic Fluid Measurement via Ultrasound

  • Amount of amniotic fluid is crucial for assessing fetal health:

    • Expected levels from 800-1200 ml in normal pregnancies.

    • Hydramnios/Polyhydramnios: Excess (>2000 ml).

    • Oligohydramnios: Insufficient (<300 ml), indicating potential fetal kidney issues.

Biophysical Profile in High-Risk Pregnancy

  • A comprehensive assessment method for high-risk pregnancies that predicts fetal well-being, integrating:

    • Fetal breathing (2 points)

    • Fetal movement (2 points)

    • Fetal tone (2 points)

    • Amniotic fluid volume (2 points)

    • Fetal heart reactivity (2 points from non-stress test).

  • Scoring interpretation:

    • Normal: 8-10 points.

    • Jeopardy: 4-6 points.

Screening for Chromosomal Anomalies and Neural Tube Defects

Quad Screen

  • Offered at 15-18 weeks gestation, evaluating maternal serum for:

    • Alpha-fetoprotein (AFP): Produced by the fetus; elevated in neural tube defects (NTD), decreased in Down’s syndrome.

    • hCG: Human chorionic gonadotropin, a placental hormone.

    • Estriol: An estrogen produced by both fetus and placenta.

    • Inhibin-A: A protein produced by placenta and ovaries.

Invasive Testing Procedures

Chorionic Villus Sampling (CVS)

  • Involves obtaining a sample of placental tissue to test for chromosomal abnormalities.

Amniocentesis Procedure

  • Conducted guided by ultrasound, typically between 15-18 weeks:

    • Indicated for chromosome analysis and assessing fetal lung maturity or fluid removal if necessary.

Rh Factor

Definition and Importance

  • Rh Factor: A protein found on the surface of red blood cells. Rh positive individuals possess this protein, while Rh negative individuals do not.

  • Importance of determining Rh factor during pregnancy:

    • If an Rh negative mother has an Rh positive baby, the mother's immune system may produce anti-D antibodies, posing risks to the fetus. Medical interventions can mitigate these risks.

Diagram of Rh Compatibility

  • Rh positive (Rh+) and Rh negative (Rh-) combinations are detailed, highlighting compatibility issues during pregnancy.

Conclusion

  • Understanding these critical aspects of fetal health assessments is vital for effective prenatal care. Awareness of potential complications, monitoring methods, and appropriate interventions ensures a healthy pregnancy outcome.