Factors and Stages of Uterine Growth
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Questions and Answers

What percentage of variability in fetal growth can be attributed to genetics?

  • 90-100%
  • 70-90%
  • 30-70% (correct)
  • 10-30%

    • Which growth factor is NOT regulated by GH during fetal development?

  • IGF-I (correct)
  • Growth Hormone itself
  • IGF-II (correct)
  • Insulin

    • What is the expected outcome in knockout mice with an IGF-I gene deletion?

  • Slow fetal development and low birth weights (correct)
  • Normal fetal development but impaired postnatal growth
  • Normal growth rates at all stages of development
  • Abnormal fetal development and normal growth after birth

    • What role does IGF-II play in fetal development according to knockout studies?

    <p>Essential for normal fetal development</p> Signup and view all the answers

    What factor is NOT associated with the physical environment affecting fetal growth?

    <p>Genetic predisposition</p> Signup and view all the answers

    What is the consequence of knocking out the GH gene in mice regarding fetal growth?

    <p>Normal fetal growth</p> Signup and view all the answers

    How does maternal SGA history relate to IUGR risk?

    <p>Increased risk of IUGR</p> Signup and view all the answers

    What describes the role of the maternal uterine environment in fetal development?

    <p>It alters fetal gene expression</p> Signup and view all the answers

    What is the primary function of IGF-I during fetal development?

    <p>Supports growth at all stages</p> Signup and view all the answers

    What is a consequence of IGF-II knockout in mice after birth?

    <p>Normal growth rates</p> Signup and view all the answers

    What is the effect of a deficiency in insulin during the fetal period as indicated by the correlation with birth weight?

    <p>Large decrease in birth weight</p> Signup and view all the answers

    In cases of Severe IUGR, which factor is low, leading to impaired fetal growth?

    <p>IGF-1 levels</p> Signup and view all the answers

    Which syndrome is characterized by a loss of paternal expression of IGF-2?

    <p>Russell–Silver syndrome</p> Signup and view all the answers

    How does IGF-2 correlate with SGA/IUGR in terms of its expression level?

    <p>Low correlation in affected cases</p> Signup and view all the answers

    Which of the following correctly associates a hormone with its correlation regarding fetal growth?

    <p>IGF-1 with reduced fat-free mass</p> Signup and view all the answers

    What is the characteristic of IGF-2 expression in Beckwith–Wiedemann syndrome?

    <p>Overexpression of IGF-2</p> Signup and view all the answers

    What is the correlation type between fat-free mass and birth weight in cases of SGA/IUGR?

    <p>Weak CW</p> Signup and view all the answers

    Which hormone is associated with less decrease in birth length in specific fetal conditions?

    <p>Insulin</p> Signup and view all the answers

    Which statement accurately reflects a common outcome in fetal growth abnormalities?

    <p>Severe IUGR can be due to mutations in IGF-1 receptors.</p> Signup and view all the answers

    What is the role of IGFBP-1 in fetal growth regulation?

    <p>Suppresses hormonal effects on growth</p> Signup and view all the answers

    What role do thyroid hormones play in fetal growth?

    <p>They are essential for normal fetal growth and development.</p> Signup and view all the answers

    How does cortisol affect IGF-1 levels during fetal development?

    <p>It decreases IGF-1 levels.</p> Signup and view all the answers

    What is the relationship between IGFBP-1 and insulin during late gestation?

    <p>Insulin increases IGFBP-1 levels.</p> Signup and view all the answers

    Which hormones are indicated to be variably increased in IUGR fetuses?

    <p>Catecholamines and IGFBP-1.</p> Signup and view all the answers

    Which of the following statements regarding growth factors and hormones in fetal development is correct?

    <p>Thyroid hormones indirectly control other hormones' effectiveness.</p> Signup and view all the answers

    What is one of the main effects of stress hormones like cortisol during pregnancy?

    <p>They inhibit linear growth by increasing IGFBP-1.</p> Signup and view all the answers

    How do sex steroids affect fetal growth differently in boys compared to girls?

    <p>They influence birth length to be slightly greater in boys.</p> Signup and view all the answers

    What effect does increased glucose and amino acid availability have on fetal hormone levels?

    <p>It increases insulin levels.</p> Signup and view all the answers

    What negative correlation is associated with glucocorticoids during fetal development?

    <p>Birth weight.</p> Signup and view all the answers

    What significant role do catecholamines play in fetal development?

    <p>They influence fetal metabolism through various mechanisms.</p> Signup and view all the answers

    What is a significant consequence of intrauterine growth retardation (IUGR)?

    <p>Risk of cognitive dysfunction</p> Signup and view all the answers

    Which of the following best describes asymmetric IUGR?

    <p>Maintained head circumference with reduced abdominal circumference</p> Signup and view all the answers

    What health risks are associated with large for gestational age (LGA) infants?

    <p>Greater likelihood of type 2 diabetes</p> Signup and view all the answers

    What is the primary factor affecting fetal cell number in symmetric IUGR?

    <p>Genetic syndrome or karyotype anomaly</p> Signup and view all the answers

    How does rapid catch-up weight gain in early childhood impact adults previously classified with IUGR?

    <p>Increased risk of hypertension and type 2 diabetes</p> Signup and view all the answers

    What defines intrauterine growth retardation (IUGR) with nutrition-related causes?

    <p>Associated primarily with placental insufficiency</p> Signup and view all the answers

    What characterizes the growth pattern of the head circumference (HC) in cases of asymmetric IUGR?

    <p>Maintained while abdominal circumference decreases</p> Signup and view all the answers

    What is one of the primary predictors of neonatal morbidity and mortality?

    <p>Birth weight</p> Signup and view all the answers

    What condition does intrauterine infection mainly contribute to?

    <p>Symmetric IUGR</p> Signup and view all the answers

    What is an expected outcome for a child with IUGR who had rapid weight gain in early childhood?

    <p>Increased risk of ischemic heart disease</p> Signup and view all the answers

    Study Notes

    Factors Controlling Uterine Growth

    • Birth weight is a key predictor of neonatal and infant survival.
    • Energy reserves are correlated with birth weight. -500g birth weight = 225 total kcal -800g birth weight = 435 total kcal -1000g birth weight = 600 total kcal -1500 =1120 -2000=1975 -3500=5924
    • Birth weight is crucial for neonatal morbidity and mortality.
    • Intrauterine growth retardation (IUGR) is linked to small gestational age and various issues like hypoglycemia, hypocalcemia, hypothermia, asphyxia, and cognitive dysfunction.
    • IUGR cases can have rapid catch-up growth in early childhood, increasing the risk of adult-onset type 2 diabetes, hypertension, preeclampsia, dyslipidemia, and ischemic heart disease.
    • Large for gestational age (LGA) infants may develop childhood weight gain, type 2 diabetes, and metabolic syndrome.

    Fetal Growth Stages

    • Normal intrauterine growth is broken down into stages:
      • Stage 1 (4-20 weeks): Hyperplasia (rapid mitosis), increasing DNA content
      • Stage 2 (20-28 weeks): Hyperplasia/hypertrophy (declining mitosis), increasing cell size
      • Stage 3 (28-40 weeks): Hypertrophy (rapid hypertrophy), rapid increasing cell size, accumulation of fat, muscle, and connective tissue
    • Growth patterns are reflected in images of femur length and fetal weight, correlated with weeks of gestation.

    Symmetric and Asymmetric IUGR

    • Symmetric IUGR (1/3 of cases): Fetus is proportionally small, affecting head circumference (HC), abdominal circumference (AC), and femur length (FL), diagnosed early. Potentially linked to early insults impacting cell number (e.g., infections, chromosomal abnormalities, or genetic syndromes).
    • Asymmetric IUGR: Often associated with "nutritional" deficiencies and issues like placental insufficiency (late 2nd/3rd trimester). Characterized by a lower abdominal circumference (AC) compared to normal head circumference (HC) and femur length (FL.) Glycogen utilization by the liver may be reduced and lead to liver shrinkage, while the body may preferentially shunt resources to the brain thus maintaining a normal head circumference (HC).

    Factors Affecting Fetal Growth

    • Genetics: Genetic factors contribute to 30-70% of growth variability. A two-fold increased risk of IUGR is present in women whose prior pregnancies resulted in small for gestational age (SGA) births.

    • Physical environment: Placental capacity and nutrient availability are important factors.

    • Interaction between genetics and environment: Maternal uterine environment can alter the fetal gene expression.

    • Adverse conditions during pregnancy: Factors such as preeclampsia, maternal malnutrition, smoking, alcohol consumption, high or low salt intake, certain drugs, and hypo-/hyper-vitaminosis contribute to growth problems. These adverse factors can impair fetal development, including potentially smaller or larger than normal birth weight, low/high nephron number, and problems with arterial remodeling. These negative factors can be associated with epigenetic modifications of DNA leading to: renal disease (like glomerulonephritis), cardiovascular disease (e.g., hypertension, coronary heart disease), and metabolic diseases (i.e., insulin resistance, dyslipidemia), creating potential long-term health issues.

    • Hormones:

      • Growth hormone (GH): Knockout mice studies indicate that GH does not regulate growth before birth but is crucial after birth.
      • Insulin-like growth factor 1 (IGF-1): Essential for growth throughout development—both before and after birth.
      • Insulin-like growth factor 2 (IGF-2): Important for fetal growth, but its role after birth is less clear.
      • Insulin: Strong correlation with birth weight; lower levels in SGA/IUGR
      • IGF Binding Proteins (IGFBP): Bind IGFs—crucial for modulating IGF activity.
      • Cortisol: Negatively correlates with birth length and varies with IUGR status.
      • Sex steroids: Show slight correlations between birth length/weight and sex.
      • Thyroid hormones: Necessary for general fetal growth and development, and have effects on the brain and somatic tissues.

    • Detailed tables present correlations between different hormones and birth weight/length.

    • Graphs show fetal hormone levels and development patterns based on weeks of gestation.

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    Related Documents

    Fetal Growth Factors : MD137 Lecture VII PDF

    Description

    Explore the factors controlling uterine growth and the different fetal growth stages. Understand the significance of birth weight and its implications on neonatal health, including risks associated with intrauterine growth retardation (IUGR) and large for gestational age (LGA) infants. This quiz offers insights into the critical stages of fetal development and their long-term health impacts.

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