WEEK 20Trimester 2•Baby: Banana
Anatomy Milestone & Sensory System Awakening
Estimated Length25.6 cm
Estimated Weight300 g
Fetal Morphogenesis & Anatomy Highlights
- •Cochlear and auditory structures functionally innervated; fetus responds to maternal cardiovascular sounds and acoustic stimuli.
- •Vernix caseosa (lipid-rich protective biofilm) covers skin against maceration.
- •Ovaries in female fetuses contain peak complement of ~6-7 million primordial oocytes.
- •Myelination of spinal cord begins.
Same-Day Assessment / Urgent Care
Week 20 Urgent Red Flags
Immediate clinical evaluation or presentation to Winnipeg Obstetric Triage (HSC / St. Boniface) is indicated if:
- •Low-lying placenta / placenta previa with painless bright red bleeding (strict pelvic rest required)
- •Shortened cervix (<25mm) or cervical funnelling (risk of preterm birth)
- •Unilateral leg swelling with calf tenderness
Women's Hospital HSC Triage: 204-787-8600 | St. Boniface: 204-237-2263
Clinician Perspective • Physiological & Screening Protocols
Maternal Physiological Adaptations
Maternal cardiac output has increased by 40%. Diastolic blood pressure reaches its physiological nadir.
Expected Clinical Symptoms
First perception of fetal movements ('quickening')—flutters or bubblesUterine fundus reaches level of umbilicus (20 cm)Mild dependent edema in feet by eveningLinea nigra and chloasma pigmentation
Clinical Investigations & Screening Schedule
- ✓Detailed Fetal Anatomical Survey Ultrasound (18–22 weeks): cranial structures, 4-chamber heart & outflow tracts, spine, kidneys, stomach bubble, abdominal wall, extremities, 3-vessel cord, placenta location, cervical length.
- ✓Repeat maternal type & antibody screen if Rh-negative.
Upcoming Visit Horizon: Prenatal visit at 24 weeks (routine fundal height, blood pressure, fetal Doppler).