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How to calculate gestational age in pregnancy?

Answered by
Dr. Indu Kumar


Practicing since :2004

Answered : 6629 Questions

Posted on Tue, 5 Aug 2014 in X-ray, Lab tests and Scans
Question: So by my lmp I'm 7 w 5 d. Ultrasound measured 6 w 3 d. heart beat is 141bpm. Dr says I must have my dates wrong and must have had sex between 12 to 16th of XXXXXXX .. but I know for a fact I didn't! The closest date we did have sex to that date was 6 XXXXXXX I'm super confused. any ideas?
Answered by Dr. Indu Kumar 22 minutes later
Brief Answer:
Calculation by LMP is more accurate.

Detailed Answer:
Hello XXXX
Thanks for writing to HCM

Gestational age by your LMP is more accurate as compared to Ultrasound.You can rely on LMP calculation.
There may be some technical error in measurement during ultrasound.This matters a lot in early gestational age.Embryo is very small in early weeks and even mm difference in measurement may alter the results.

You don't worry at all.LMP calculation is more accurate in early weeks.
With advancement of pregnancy,ultrasound will give more accurate maturity results.
Heart beat is also normal.

Wish you safe and healthy pregnancy.
Hope I have answered your question.
Further queries are most welcome.

Take Care
Above answer was peer-reviewed by : Dr. Chakravarthy Mazumdar

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