Baby Growth Calculator

Track your baby's growth and development during pregnancy. See fetal size, weight, development milestones, and organ maturation by gestational age.

Baby Growth Calculator

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Track Baby's Growth

Enter gestational age to see your baby's current development and milestones.

How to Use the Baby Growth Calculator

  1. Enter Gestational Age: Input how many weeks pregnant you are
  2. Choose Calculation Type: Select standard calculation or include ultrasound measurements
  3. Add Ultrasound Data (Optional): Enter BPD, HC, AC, FL measurements from recent scans
  4. Calculate Growth: Click to see your baby's current development status
  5. Review Results: See size estimates, organ development, and milestones
  6. Track Progress: Use regularly to monitor your baby's growth journey

Fetal Development Timeline

First Trimester (1-12 weeks)

• Neural tube formation
• Heart begins beating (6 weeks)
• Major organs form
• Arms and legs develop
• Reflexes begin

Second Trimester (13-26 weeks)

• Gender visible on ultrasound
• Movement begins (18-20 weeks)
• Hearing develops
• Viability reached (24 weeks)
• Brain growth accelerates

Third Trimester (27-40 weeks)

• Eyes open and close
• Rapid brain development
• Lungs mature
• Weight gain accelerates
• Preparation for birth

Understanding Ultrasound Measurements

Key Measurements

BPD (Biparietal Diameter)
Distance across the baby's head from temple to temple
HC (Head Circumference)
Measurement around the baby's head
AC (Abdominal Circumference)
Measurement around the baby's abdomen
FL (Femur Length)
Length of the thigh bone

What They Tell Us

Growth rate and overall development
Estimated fetal weight and gestational age
Proportional development of different body parts
Comparison to population averages (percentiles)
Detection of potential growth concerns

Baby Size Comparison Chart

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8 weeks
Raspberry
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15 weeks
Apple
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20 weeks
Banana
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40 weeks
Watermelon

Frequently Asked Questions

How accurate are fetal growth estimates?

Growth estimates are based on average development patterns and can vary by ±15-20%. Ultrasound measurements provide more accurate estimates than gestational age alone, especially when multiple measurements are taken over time.

What if my baby measures larger or smaller than average?

Babies grow at different rates, and size variations are normal. Your healthcare provider will monitor growth trends over multiple visits. Consistently measuring very large or small may indicate the need for closer monitoring.

When do major organs finish developing?

Most major organs form during the first trimester, but continue maturing throughout pregnancy. The brain and lungs are among the last to fully mature, with significant development continuing until birth and beyond.

What is fetal viability?

Viability refers to the ability to survive outside the womb with medical support. It's generally reached around 22-24 weeks, with survival rates improving significantly each week thereafter.

Should I be concerned if measurements don't match my due date?

Small discrepancies are normal and may lead to adjusted due dates early in pregnancy. Your healthcare provider will evaluate growth patterns and overall development rather than focusing on single measurements.