Low Birth Weight and Prematurity

Definitions & Classifications - Tiny Tots Tagged

Gestational Age (GA) Categories:

• Small for Gestational Age (SGA): BW <10th percentile for GA.

  ⭐ SGA infants (BW <10th percentile for GA) face ↑ perinatal morbidity & mortality vs. AGA infants, even if not LBW.

• Appropriate for Gestational Age (AGA): BW 10th-90th percentile for GA.
• Large for Gestational Age (LGA): BW >90th percentile for GA.
• Intrauterine Growth Restriction (IUGR): Pathological fetal growth restriction, often leading to SGA.

Etiology & Risk Factors - Preemie Triggers

• Maternal Factors:
  • Previous preterm birth (PTB) - strongest risk
  • Multiple gestation (twins, triplets)
  • Uterine/cervical issues: incompetent cervix, fibroids, Müllerian anomalies, short cervix (<25 mm)
  • Infections: UTI, BV, chorioamnionitis, periodontal disease
  • Chronic illness: HTN, DM, renal, thyroid, autoimmune
  • Preeclampsia, eclampsia
  • Placental: abruption, previa, insufficiency
  • Polyhydramnios/Oligohydramnios
  • Age: <18 or >35 yrs
  • Low SES, poor nutrition, stress
  • Substance abuse (smoking, alcohol, illicit drugs)
  • Short interpregnancy interval (<18 months)
• Fetal Factors:
  • IUGR, macrosomia (rarely)
  • Congenital anomalies
  • Fetal distress, hydrops
• Iatrogenic Preterm Delivery (medically indicated)

⭐ Prior preterm birth is the single most important risk factor for subsequent preterm birth, increasing the risk by 2-3 times.

Complications of Prematurity - Fragile Fighters' Foes

• Respiratory:
  • RDS (Surfactant deficiency; ground glass CXR)
  • BPD (O₂ need at 36wks PMA / 28d postnatal)
  • Apnea of Prematurity (>20s pause)
• Neurological:
  • IVH (Germinal matrix; Grades I-IV; US screen)
  • PVL (White matter injury; ↑CP risk)
  • ROP (Screen <32wks / <1500g; Zones I-III, Stages 1-5)
• Gastrointestinal:
  • NEC (Bowel necrosis; pneumatosis intestinalis)
  • Feeding intolerance
• Cardiovascular:
  • PDA (Continuous murmur)
  • Hypotension
• Hematologic/Metabolic:
  • Anemia, Hyperbilirubinemia
  • Hypoglycemia, Hypocalcemia, Hypothermia
• Infectious:
  • Sepsis (Immature immunity)
• Long-term: Neurodevelopmental delay, growth failure.

⭐ IVH is most common in infants <1500g or <32 weeks gestation, typically occurring in the first 72 hours of life.

Management Strategies - Little Lives Lifelines

• Antenatal (Threatened PTL):

  • ACS: Betamethasone (12mg IM x2, 24h apart) or Dexamethasone (6mg IM x4, 12h apart) for PTL <34 wks (up to 36+6 if no prior).
  • Tocolysis (Nifedipine): Delays delivery 48h for ACS.
  • $MgSO_4$: Neuroprotection if PTL <32 wks (4g load, 1g/hr).

• Delivery Room ("Golden Hour"):

  • Warmth (23-25°C), radiant warmer, poly-wrap (VLBW/ELBW).
  • Delayed Cord Clamping (30-60s).
  • Respiratory: CPAP/intubation; surfactant (RDS).

• Postnatal:

  • KMC: Skin-to-skin, early breastfeeding.
  • Nutrition: Trophic feeds (human milk), fortification (VLBW), PN prn.
  • Respiratory: Target $SpO_2$ 90-95%; caffeine (apnea).
  • Screen: IVH (US), ROP. Infection control.

⭐ Antenatal $MgSO_4$ for PTL <32 weeks significantly reduces cerebral palsy risk.

High‑Yield Points - ⚡ Biggest Takeaways

• LBW < 2500g; VLBW < 1500g; ELBW < 1000g. Prematurity is birth < 37 weeks.
• Key complications: RDS, IVH, NEC, ROP, PDA, sepsis, long-term neurodevelopmental delay.
• Antenatal corticosteroids (given 24-34 weeks gestation) reduce RDS, IVH, and neonatal mortality.
• Exogenous surfactant is vital for RDS management in preterm infants.
• Kangaroo Mother Care (KMC) significantly improves survival and outcomes in LBW infants.
• Common causes of prematurity: PPROM, maternal infections (e.g., UTI, chorioamnionitis), multiple gestation.