Get E-Book on COVID-19

Q. The gestational age in scan is different from the weeks when calculated from my LMP. Why?

Answered by
Dr. Eeshani Dutta
and medically reviewed by iCliniq medical review team.
This is a premium question & answer published on Feb 19, 2019

Hello doctor,

I am 27 years old and pregnant. My last period was two months back but the baby only shows six weeks and three days gestation as of today with a heart rate of 77. I have a picture of my ultrasound from today and I was hoping you could explain what it was showing.

Dr. Eeshani Dutta

Obstetrics And Gynaecology
#

Hi,

Welcome to icliniq.com.

For a lady, with regular periods previously, generally ovulation occurs around 14th day of the cycle, so fertilization can take place only after that. In your case (if your periods are regular), you ovulated around 22nd two months back and fertilization took place only after that. So originally, the baby will always be two weeks less than what is calculated by LMP.

Secondly, first-trimester USG can have an error of up to seven days while second and third trimester up to 2 and 3 weeks respectively, so do not worry if the calculation and USG are not exactly the same.


Was this answer helpful?

 | 

Related Questions:
How to find the exact date of conception?
Is it dangerous to stay in a smoking hotel room when pregnant?
Is it true that rest will increase FL and HL of a fetus?
Consult by PhoneConsult by Phone Video ChatVideo Chat
Also Read Answers From:

Comprehensive Medical Second Opinion.Submit your Case

Related Questions & Answers


Had an emergency contraceptive pill after sex. Can I be pregnant?

Query: Hi doctor, I am 21 years old and my menstrual cycle is generally of 30 days. Last month I had sex with my boyfriend on just after 2 days of my periods. Though we used condoms but I felt as if it was leaking so to be double sure I took one Unwanted 72 in 23 hours. Now, I am 13 days late for my period...  Read Full »

How to find out if an ECP used 72 hours after unprotected intercourse was effective?

Query: Hi doctor, I had unprotected intercourse with my fiance during the first week of last month. Same week, within few days she complained about vomiting sensation but had no vomiting. Immediately the next day she had a little discharge from vagina and a little menstrual cramp. Her last menstrual perio...  Read Full »

The doctor cannot find the baby's heartbeat. Should I be concerned?

Query: Hello doctor, My wife is 49 days pregnant. Today we met our doctor. He said that the fetal size is 0.63 cm, but still, there is no heartbeat felt. The doctor asked us to wait for one more week. Is it normal? Please clarify my doubt. My wife is worried about this. This is our second baby.  Read Full »

Also Read


COVID-19 and MIS-C (Multisystem Inflammatory Syndrome in Children)
MIS-C is a potentially fatal condition that affects children infected with COVID-19. Please read the article to know its...  Read more»
I have fever, severe headache, and cough. Please help me.
I have fever since five days. My fever comes down when I take medicine but eventually comes back. I also have severe hea...  Read more»
Brucellosis - Symptoms, Complications, Diagnosis, and Treatment
Brucellosis, a zoonosis, is caused by consuming unpasteurized milk or raw meat obtained from infected animals. For sympt...  Read more»

Ask your health query to a doctor online?

Ask an Obstetrician & Gynaecologist Now

* guaranteed answer within 4 hours.

Disclaimer: All health Q&As published on this website is not intended to be a substitute for professional medical diagnosis, advice or treatment by a trained physician. Seek the advice from your physician or other qualified health-care providers with questions you may have regarding your symptoms and medical condition for a complete medical diagnosis. Do not delay or disregard seeking professional medical advice because of something you have read on this website.