WEEK 24Trimester 2•Baby: Cantaloupe / Ear of Corn
Viability Threshold & Canalicular Lung Stage
Estimated Length30 cm
Estimated Weight600 g
Fetal Morphogenesis & Anatomy Highlights
- •Threshold of legal and physiological viability: intensive neonatal resuscitation possible in tertiary NICUs (such as HSC Winnipeg NICU).
- •Canalicular phase of pulmonary development: terminal bronchioles divide into respiratory bronchioles, forming early primitive alveolar sacs.
- •Type II pneumocytes begin producing surfactant, reducing alveolar surface tension.
- •Rapid eye movement (REM) sleep states observed on neurosonography.
Same-Day Assessment / Urgent Care
Week 24 Urgent Red Flags
Immediate clinical evaluation or presentation to Winnipeg Obstetric Triage (HSC / St. Boniface) is indicated if:
- •Regular painful uterine contractions > 4-6 per hour (threatened preterm labour)
- •Sudden gush or slow persistent trickling of clear vaginal fluid
- •Persistent right upper quadrant or epigastric pain
Women's Hospital HSC Triage: 204-787-8600 | St. Boniface: 204-237-2263
Clinician Perspective • Physiological & Screening Protocols
Maternal Physiological Adaptations
Fundal height measures approximately 24 cm (+/- 2 cm). Maternal insulin resistance increases under placental lactogen (hPL), cortisol, and progesterone.
Expected Clinical Symptoms
Braxton Hicks contractions (sporadic, irregular, painless tight sensations)Lower back ache due to altered center of gravity and lumbar lordosisMild ankle edemaHeartburn/GERD due to relaxed LES
Clinical Investigations & Screening Schedule
- ✓Gestational Diabetes Screening (24–28 weeks): 50-gram Glucose Challenge Test (GCT).
- ✓Interpretation (SOGC Guidelines): < 7.8 mmol/L is normal; 7.8–11.0 mmol/L warrants diagnostic 75g 2-hour OGTT; >= 11.1 mmol/L is diagnostic of Gestational Diabetes Mellitus (GDM).
- ✓CBC for physiologic anemia of pregnancy (hemoglobin < 105 g/L in 2nd trimester defines anemia).
Upcoming Visit Horizon: Routine 28-week visit (start of 3rd trimester).