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What is the most common / popular birth day?


Based on the most recent official data from US Census Bureau, the most popular birth day is Oct. 10th. This output is based on the records of 244 millions of americans, which accounts for 93% of the total registered populations.

Why Oct. 10th is the most popular birth day?

You may wonder what is the possilbe reason for Oct. 10th to be the most popular birth day, It's most likely due to the New Year celebration!

Based on the formula to calculate the baby deliver date by Dr. Naegele:

Deliver Date= (Romance Time +7 Days) - 3 Months
For example, if the romance time happens at New Year, then the baby deliver date would be:
(Jan. 1 +7 Days) -3 months =Oct. 8th.

He determined that the average length of human gestation was approximately 266 days from conception, and assumed that the average woman had cycles that lasted 28 days and that she ovulated on Day 14 of her cycle.

However, Dr. Naegele did not consider certain factors in his calculation. For example: Not every woman ovulates on Day 14. Other situations that he did not factor in were ethnicity, parity (how many successful pregnancies), prenatal care, better nutrition, and screening factors.

Today we still use Naegele's rule to determine due dates. However, there is a new rise to the discussion of the accuracy of Naegele's findings. With the advent of true prenatal care, midwives and physicians are helping women educate themselves about risk factors, nutrition and prenatal screening. This extends the lengths of gestation for many women.

One study indicates that we need to:

add 15 days to the Naegele EDC for Caucasian, first time moms,

add 10 days for Caucasian moms having subsequent children

African American and Asian women tend to have shorter gestations.

Now because of the delay, most baby would be born after Oct. 8th, and it comes out at Oct. 10th, by the most recent Census information.

The 2nd-9th most popular birth day are: Sep. 9, Sep. 15, Sep 10, Sep. 21, Aug. 15, Sep. 23, Aug. 8, Sep. 17, Oct. 1.

The least common birth day are: Feb. 29, it's due to the fact that, Feb. 29 showed up only one time in every 4 years(leap year). In other words, for those people having birthday on Feb. 29th, they can only have one birth day in every 4 years!

The other least common birth day are followed by Dec. 26, Dec. 25, Dec. 24, Mar. 31, it's possibly due to the holiday, many people want to either delay the delivery or get the baby earlier to celebrate the holiday.



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