There are about 3.6 million babies born in the U.S. each year, which is an average of 9,863 a day. Here’s a look at pregnancy and birth in the U.S.
Conception to birthdate
The length of the average pregnancy is approximately 266 days. As the exact estimate of the ovulation is usually not known, an estimate of the birthdate is made using the day of the last menstrual period. This is usually 14 days before ovulation, so 14 days are added to the figure of 266, making a total of 280 days, or 40 weeks.
Only about 5% of women actually give birth on the exact date they are due.
Calculating the birthdate
The usual way doctors estimate the expected delivery date is to count back three months from the first day of the last menstrual period and add seven days. For example, if the last menstrual period began May 12, the expected delivery would be Feb. 19 (May 12 minus three months + Feb. 12 plus seven days.
Table below shows conception (a) and birthdate (b).
Average baby
In the U.S., the average baby weighs just over 7 pounds and is 19½ inches long.