Am i pregnant

How Many Weeks Pregnant Are You?

Q: 4. Is fetal age more accurate than gestational age?

Yes, fetal age is generally more accurate. Since it measures from actual fertilisation, fetal age is better for women with irregular cycles, shortened cycles, or longer cycles.

Q: 5. How many weeks are there in a full pregnancy?

A full pregnancy is considered 40 weeks gestational age. This equals 38 weeks from the time of ovulation.

Q: 6. How do I calculate my due date?

You calculate your due date using Naegele’s rule. Add 7 days to the first day of your LMP, then add 9 months. This estimates a 40 week pregnancy.

Q: 7. Do babies arrive on their exact due date?

No, only 3–5% of babies arrive exactly on the due date. Most babies arrive around 40 weeks + 3 days, and healthy babies can be born anytime between 37–42 weeks.

Q: 8. What are pregnancy trimesters?

Pregnancy trimesters are three stages of 12 weeks each. Each trimester marks important changes in your body and your baby’s development.

Dear mum, by now you’re fairly certain that you’re pregnant — congratulations! Yet answering the simple question “How many weeks pregnant?” is not always easy. There are actually two valid systems used today to calculate it: gestational age and fetal age.

Gestational Age

Gestational age is the traditional method used for generations. Because ovulation and fertilisation have no outward signs and cannot be precisely dated, this method counts from Day 1 of your Last Menstrual Period (LMP).

LMP typically occurs 2 weeks before ovulation
Weeks counted from the LMP become your gestational “weeks pregnant”
It amusingly means you are “2 weeks pregnant” at ovulation!
Gestational term is 40 weeks (280 days) from LMP
Still commonly used to calculate your due date

This is a simple, informal measure — what many mothers have always used.

Fetal Age (Ovulation System Age)

Fetal age is the actual age of your baby — meaning the number of weeks since fertilisation.
It relies on modern technology such as ultrasound or ovulation testing, making it more precise than gestational age.

Based on actual fertilisation timing
Highly accurate for shorter or longer cycles (not 28 days)
Not dependent on the assumption that ovulation happens 14 days after LMP

For women with irregular cycles, fetal age offers greater accuracy.

Understanding Pregnancy Trimesters

Pregnancy is commonly divided into 3 trimesters, each about 12 weeks long.
These stages represent major differences in:

Your symptoms and physical changes
Your baby’s development

How Long Will Your Pregnancy Last?

he classical method to estimate your due date is Naegele’s rule:

Add 7 days to the 1st day of your LMP
Add 9 months to the month

Example:
If your LMP started on 18 November, your estimated due date becomes 24 August.
Naegele’s rule assumes:

A 28 day cycle
Ovulation and fertilisation on Day 14
Total gestation: 38 weeks from ovulation
Or 40 weeks from LMP

However:

Only 3–5% of babies arrive exactly on their due date
Most common arrival time: 40 weeks + 3 days
Babies born between 37 and 42 weeks of gestation can be perfectly healthy

Kimberly-Clark India makes no warranties or representations regarding the completeness or accuracy of the information. This information should be used only as a guide and should not be relied upon as a substitute for professional medical or other health professional advice.

FAQ Section

You are as many weeks pregnant as the number of weeks since your LMP (gestational age). Gestational age counts pregnancy from Day 1 of your last menstrual period. Alternatively, your doctor may use fetal age, which is usually 2 weeks less and measured via ultrasound or ovulation tracking.

Gestational age counts from the LMP, while fetal age counts from fertilisation. Gestational age assumes ovulation occurs 14 days after LMP, while fetal age uses more accurate tools like ultrasound or ovulation testing.

Gestational age is used because it’s simple and traditionally accepted. Women can easily recall their LMP, making it a convenient informal method to estimate how many weeks pregnant they are.

Yes, fetal age is generally more accurate. Since it measures from actual fertilisation, fetal age is better for women with irregular cycles, shortened cycles, or longer cycles.

A full pregnancy is considered 40 weeks gestational age. This equals 38 weeks from the time of ovulation.

You calculate your due date using Naegele’s rule. Add 7 days to the first day of your LMP, then add 9 months. This estimates a 40 week pregnancy.

No, only 3–5% of babies arrive exactly on the due date. Most babies arrive around 40 weeks + 3 days, and healthy babies can be born anytime between 37–42 weeks.

Pregnancy trimesters are three stages of 12 weeks each. Each trimester marks important changes in your body and your baby’s development.

Your due date may change if the fetal age measured on ultrasound differs from your LMP-based date. Early ultrasounds are highly accurate for determining fetal age.

Use gestational age for everyday tracking and fetal age for medical accuracy. Healthcare professionals often reference both during pregnancy.