Is Pregnancy 9 or 10 Months Long?

Is Pregnancy 9 or 10 Months Long?

Feel like your pregnancy is never ending? Ever tried to add things up and get the feeling like you've been pregnant a lot longer than 9 months? Especially when you have 100 doctor appointments leading up to the delivery. Well, the truth is that pregnancy is actually ONLY 9 MONTHS LONG.

It's not a surprise that we get confused--especially when a full-term pregnancy is 40 weeks. You may say, "Okay, 40 weeks divided by 4 weeks (4 weeks in each month) is 10 months." Ta da! Well not so fast mama...not every month has only 4 weeks! Since I am blessedly out of the pregnancy brain phase and can sort of help break things down for you, here's the explanation for how pregnancy actually lasts only 9 months.
Because every month (minus February) is actually longer than 4 weeks, you can't simply divide 40 weeks by 4 weeks. To make this simple, let's take pregnancy by days only. Your due date is determined by counting 280 days from the day of your last period. So let's do the math here. When you take 280 and divide it by 30 (all months, except February, have 30 days), you'll get 9.33 months. Now, you might pause here and say, "Well, look, 9.33 is MORE than 9 months." Just wait! Remember, you aren't ACTUALLY pregnant for about two weeks after the first day of your last period. SO, let's take 14 days away from 280. Now you actually have 266 days that you're ACTUALLY pregnant. Take 266 and divide that by 30 (average number of days in a month), and you'll get 8.8 months. 8.8! Oh no! You're not even really pregnant for NINE WHOLE MONTHS! Do you feel a little bit cheated now? So sorry! If you're angry at the math side of things, then just count it on your fingers. If a person had their last period on December 12th, they would have a due date of September 18th. December to January is 1 month, January to February is 2 months, February to March is 3 months, March to April is 4 months, April to May is 5 months, May to June is 6 months, June to July is 7 months, July to August is 8 months, and August to September is 9 months. Absolutely no 10-month-long timelines here mamas! Rest assured, even though that last month actually does feel like it's a year long, and your ankles are swollen so big that there is clearly no blood circulating to your brain, it's nice to know that you're not the only one who feels like there is no way that pregnancy only lasts for 9 months!

But hey, at least you're a human and not an elephant with a terrifyingly long gestational period (almost two years if you didn't know!). XO

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Thank You for this I knew the very second I got pregnant with my last son and knew the day he would be born and it wasn’t 10 months it was 9 months I missed the day he would be born by 1 day I said the 13th he was born the 14th he weighed 9lb 3oz, and was 23 1/2 inches long there is no way I could have went 10 months


THANK YOU for this! I know it seems a little pedantic, but for some reason it drives me nuts when people say pregnancy is ten months. It’s simply not true, and it all just comes down to very basic math. I’ve had two pregnancies, one which went significantly overdue, so I’m not just some smug jerk whose never been there. This is one of the best breakdowns I have seen explaining that it’s NINE months, not ten.


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