Second Trimester • 4 months

18 Weeks Pregnant: Baby Size, Symptoms & Due Date Milestones

Comprehensive gestational timeline analysis, fetal growth metrics, anatomical development, and personalized due date milestones for week 18.

Gestational Classification
At 18 weeks pregnant, you are in your Second Trimester

Equivalent to 4 months • 126 calendar days of gestation completed

Overall Gestational Progress 45.0% of 40 Weeks (126 of 280 Days)
Days Pregnant
126 Days
Exact duration
Days Until Due Date
154 Days
22.0 weeks left
Trimester Stage
2nd Trimester
Weeks 14 – 27
Fetal Size Category
Bell pepper
14.2 cm

Baby Development at 18 Weeks Pregnant

Baby Size Comparison
Bell pepper

Fruit / Vegetable Analogy

Estimated Length
14.2 cm

Crown to Rump (CRL)

Estimated Weight
190 g

Fetal Weight Standard

Week 18 is an exciting stage for sensory development. The auditory system is functioning: the baby can hear the maternal heartbeat, digestive gurgles, and outside voices filtered through amniotic fluid.

A protective fatty insulating layer called myelin begins wrapping around nerve fibers in the spinal cord and brain. Unique fingerprints and toe prints are completely formed and permanent.

Personalized Due Date Recalculator

Input your last menstrual period (LMP) to verify your exact week, remaining days, and estimated delivery date.

Real-Time Engine
Recalculated Due Date
Select your LMP date
Days Remaining
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Current Gestation
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Disclaimer: Computational estimates are based on standard clinical algorithms (e.g., Naegele's rule) for educational and planning purposes only. They do not constitute formal medical evaluation, diagnosis, or clinical obstetrics advice.

Disclaimer: Computational estimates are based on standard clinical algorithms (e.g., Naegele's rule) for educational and planning purposes only. They do not constitute formal medical evaluation, diagnosis, or clinical obstetrics advice.

Maternal Symptoms & Clinical Guidance at Week 18

Common Physical Symptoms

  • Distinct fluttering or gentle tapping sensations in your belly
  • Mild dizziness when rising quickly from seated or reclining positions
  • Increased leg cramps, particularly in the calves at night
  • Swelling in feet and hands after warm weather or activity

Clinical Action Items

  • Stretch calf muscles before bedtime to ward off nocturnal cramps
  • Ensure adequate dietary magnesium and potassium (bananas, avocados, nuts)
  • Talk and sing to your baby—they can hear your voice clearly now!
  • Prepare any specific questions for your upcoming anatomy scan

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Frequently Asked Questions About 18 Weeks Pregnant

Yes. The bones of the inner ear and nerve endings in the brain are developed enough for the baby to detect auditory sounds, particularly your vocal vibrations and steady heartbeat.