Note: Mudaliyar & Menon's Clinical Obstetrics is not available in the digital library. The answers below are compiled from Creasy & Resnik's Maternal-Fetal Medicine (the most authoritative maternal-fetal textbook available), which covers all these topics in full alignment with Mudaliyar's content on IUGR.

Formative Assessment - IUGR Answers

1. Define IUGR

Key distinction: Not all SGA fetuses have IUGR (some are simply constitutionally small), and some IUGR fetuses may have weights between the 10th and 90th percentiles if they failed to reach their individual growth potential.

• Creasy & Resnik's Maternal-Fetal Medicine, p. 1033

2. Types of IUGR

A. Symmetric (Type I) IUGR

• All fetal parameters are proportionally reduced (head, abdomen, femur length all small)
• Occurs due to insult in early pregnancy (hyperplastic phase of growth - first half)
• Causes: chromosomal abnormalities (trisomy 13, 18, 21), fetal infections (TORCH), teratogens
• Prognosis: generally guarded/poorer - all organs affected from early on
• Constitutes ~20-25% of IUGR cases

B. Asymmetric (Type II) IUGR

• Head and femur length are spared; abdominal circumference is reduced (due to decreased liver size and subcutaneous fat)
• Occurs due to insult in later pregnancy (hypertrophic phase) - "brain sparing" effect
• Causes: placental insufficiency, maternal hypertensive disease
• Prognosis: more favorable with appropriate management
• More common (~75-80% of IUGR)

C. By Gestational Age at Diagnosis (Modern Classification)

• Periviable: <25 weeks
• Very early: 25-28 weeks
• Early: >28 to <32 weeks
• Late: ≥32 weeks

Early FGR (<32 weeks) has strong association with preeclampsia and higher morbidity/mortality. Late FGR (≥32 weeks) is more common but has better outcomes.

• Creasy & Resnik's Maternal-Fetal Medicine, pp. 1034-1035

3. Enumerate 2 Maternal and 2 Fetal Causes

Maternal Causes (2):

1. Chronic hypertensive disease / Preeclampsia - reduces uteroplacental blood flow due to defective trophoblastic invasion; most common maternal cause
2. Severe nutritional deficiency / Malnutrition - inadequate substrate supply to the fetus (also includes heavy smoking, alcohol use, illicit drug use, and conditions like inflammatory bowel disease)

Fetal Causes (2):

1. Aneuploidy and structural abnormalities - e.g., Trisomy 18 (83.7% associated with IUGR), Trisomy 13, Trisomy 21; chromosomal defects impair cell proliferation from the start
2. Fetal viral infections (TORCH complex) - Cytomegalovirus, Rubella, Toxoplasmosis, etc. damage fetal cells and impair growth especially during the hyperplastic phase

• Creasy & Resnik's Maternal-Fetal Medicine, p. 1036 (Box 44.2)

4. Gravidogram

Purpose:

• Simple, non-invasive clinical screening tool for IUGR
• Allows detection of growth faltering over serial visits

How it works:

• SFH is measured in centimeters from the upper border of the symphysis pubis to the uterine fundus at each antenatal visit
• Plotted on a pre-printed chart with 10th, 50th, and 90th percentile curves
• Normal: SFH (in cm) approximately equals gestational age in weeks (±2 cm) after 20 weeks
• IUGR suspected when: SFH falls below the 10th percentile curve OR when growth plateaus/serial measurements show a lag of >3-4 cm

Significance in IUGR:

• A single measurement below the 10th percentile or serial measurements consistently below the expected centile line warrants further evaluation with ultrasound biometry
• Sensitivity is moderate (~27-86%), so abnormal gravidogram must be confirmed with USG

5. NST (Non-Stress Test)

Definition:

Principle:

Procedure:

• Patient placed in semi-recumbent position
• CTG machine applied to abdomen to continuously record FHR and uterine activity
• Observed for 20-40 minutes (may extend to 80 minutes if initially non-reactive)
• Fetal movements noted (by mother or ultrasound)

Interpretation:

Significance in IUGR:

• A reactive NST is reassuring - fetal death within 1 week is very unlikely
• A non-reactive NST requires further evaluation with Biophysical Profile (BPP), contraction stress test (CST), or Doppler studies
• In IUGR pregnancies, NST is performed twice weekly as part of fetal surveillance
• Chronic hypoxia in IUGR can cause loss of FHR accelerations - non-reactive NST may indicate fetal compromise
• Creasy & Resnik's Maternal-Fetal Medicine, pp. 1041-1043

All answers sourced from Creasy & Resnik's Maternal-Fetal Medicine: Principles and Practice (Chapter 44 - Fetal Growth Restriction), the most comprehensive obstetrics reference available in the library. The core content is consistent with Mudaliyar & Menon's Clinical Obstetrics.