Obstetrics
PROTOCOLS
SECOND TRIMESTER
Fetal organogenesis standards and maternal physiological adaptation. Biometry guide and metabolic markers.
Editorial Signature: Dr. Belh
1. Morphological Evolution
The second trimester (Weeks 13-26) marks the transition from embryo to fetus. It is a period of functional maturation of organ systems and anatomical refinement.
Developmental Mutation
The integumentary system develops, transitioning from transparency to opacity via subcutaneous fat. Meconium initiates intestinal production.
Neuro-Sensory Activation
By the 5th month: sucking reflex and auditory processing. Formation of lanugo and vernix caseosa.
2. Clinical Principles
Biometric
Correlation
Growth Velocity
Regular ultrasound measurement to validate gestational age standards.
Metabolic
Adaptation
Glucose/Iron Monitoring
Monitoring insulin resistance is mandatory (prevention of gestational diabetes).
Mechanical
Optimization
Center of Gravity
Postural adjustments required to counteract lordosis and sciatic compression.
3. Required Screenings
| Diagnostic Procedure | Time Window | Clinical Objective |
|---|---|---|
| Alpha-fetoprotein (AFP) | Week 16 – 18 | Screening for neural tube defects & chromosomal abnormalities. |
| Morphological Ultrasound | Week 20 – 22 | High-resolution analysis of structures & placenta. |
| O’Sullivan Test | Week 24 – 28 | Glucose challenge test (Gestational Diabetes). |
| Amniocentesis | Variable | Conditional invasive diagnostic (Genetic). |
4. Mitigation Strategies
01
Sciatic Neuropathy
Managed by pelvic tilt and avoidance of prolonged standing.- 02
Hemodynamic Cramps
Requires hydration and magnesium to counteract venous stasis. - 03
Gastrointestinal Motility
Managed by proactive fiber intake (25-30g/day), non-laxative.
5. Visual Reference
QUICK FAQ
Timeline
Exact start and end?
From the start of week 13 to the end of week 26.
Movements
Predictability?
Typical perception between weeks 18 and 22.
Cramps
Clinical significance?
Indicate electrolyte imbalances or circulatory strain.
Diabetes
Why O’Sullivan?
Primary screening tool for asymptomatic gestational diabetes.