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A 10 Month Pregnancy?

Is a pregnancy nine months or ten months long? This is a popular pregnancy debate with many women across message boards and in pregnancy communities today. Most people know that a pregnancy consists of the first, second and third trimester. The definition of a trimester is “A period or term of three months”. If this is the case, why do so many people consider themselves pregnant for ten months?ย  The answer is simple, even if not actually correct. Pregnancies are considered full term at 40 weeks, and many women count four weeks as a month while they are pregnant, making the result a ten month pregnancy. On average there are actually 4.33 weeks in a month, however that a third of a week tends to get lost in the pregnancy shuffle for much of us.

Many women also find it easier, when asked how pregnant they are, to answer in weeks instead of months, because pregnancy is generally a count down. “I am 24 weeks, only 16 weeks to go!” The most general deduction by a bystander would be that the woman is already six months pregnant, when in actuality, per the Gregorian calendar that most of the world lives by, she is only about five and a half months pregnant.

Women who consider themselves 10 months pregnant usually use this form of calculations:

1-4 1
9-12 3
17-20 5
25-28 7
33-36 9

For those that live by the Lunar calendar, this not only makes sense, but is absolutely correct. The Lunar calendar, which is the four weeks it takes for the moon to go from a new moon, to a full moon and back again, would make a pregnancy last for ten months.

For those that live by the Gregorian calendar, and counting by the date you started your last period (letโ€™s say October 15), you would not be one full month pregnant until November 15 and the calculations generally look like this:

November 15 1
January 15 3
March 15 5
May 15 7
July 15 9

However, neither of these calculations is exactly accurate. The most common way to figure out your due date, including the way that most doctors calculate it, is to add nine months and seven days to the start date of your last menstrual period, which would actually be a week before you would have ovulated with a 28-day cycle. Therefore, if you started your LMP on October 15, you due date would be calculated as July 22, not July 15.

November 15 1 4.33
January 15 3 13 (start of second trimester)
March 15 5 21.66
May 15 7 30.33
July 15 9 39

This would make your due date of July 22 be at 40 weeks exactly, or nine months and one week after you started your LMP. This being said, why would someone CHOOSE to be pregnant for ten months?

Another way to look at it is if you consider a pregnancy of 40 weeks to be ten months, and that a year has 52 weeks in it – which you also count four weeks as one month – wouldn’t this mean that your baby would be 13 months old before he turned a year, and you could celebrate his first birthday?

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45 Comments on "A 10 Month Pregnancy?"

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3 years 4 months ago

I am 9days late I was suppose to start 01-02-16 I feel different boobs hurt eating more but I woke up and when I wiped it was light pink so am I pregnant or going to start my period?!? Could I bleed still if I was??

3 years 4 months ago

my wife is about ten months pregnant.
her doctor told her she should expect delivery on the 25th December 2015. but today is 4th January , 2016 .
i want to find out if the baby stands out any complications,
or is there any risk to the unborn baby? and what should we do? is CS only the option. am worried

4 years 1 month ago
Hi… I am 8 weeks pregnant… Or so the gp said (calculating from my LMP)… Anyway i wasnt really in a relationship with my babys father till before all this came out and im really unsure whether we are now… I know alot has changed though. He is very supportive though. Never doubted or questioned me. Thing is the guy should know when the possibility is there. Also what helped alot for me is that the father has the cravings and mood swings. So the gp as well as online calculators said im due end Nov (28-30) which would make… Read more »
7 years 1 month ago

Actually….I am not sure when an egg can be said to be “launched into the womb”. Please will someone tell me? I guess that the progress of the egg from the ovaries to the fallopian tube and then into the womb is fairly analogue and flexible.

In Japan pregnancy was felt to be 10 months (female body months) and ten days long since the egg was deemed to have been pregnant from the start of the previous period, i.e. when the previous egg made way for the next.

7 years 7 months ago
to confused, the ultra-sounds def can not always predict ur dates. the bigger the baby gets the more off the ultra-sound are. its actually better to go by the earliest ultra sound dates then the later ones. thats why they change the estimated due dates so much and its y only 4 women out of many actually due give birth around there estimated due date. i can understand fully why people question it even when the ultrasounds give them a date. we know when we had sex. not some machine or doctor does know it better then us actual people… Read more »

[…] account your last period and assume conception took place a week after that date. They then add nine months to that date to give you the estimated due […]

al r.
7 years 11 months ago

I was in my mother ten months and I have had problems from day one. I am 57 and learned secrets of my own life in the last 10 years. I wish my parents treated me as a child. I complained of pain and they humiliated me.

uzoma sybil
8 years 1 month ago

A sister was pregnant in April 2008 and gave birth in 13th of March 2009,the child was a still birth.after one week she resumed her normal sexaul life,which resulted in her been pregnant within one month of her last delivery,that is by April 2009 she was pregnant, and she carried the baby to july 2010(15 -16months)can it be possible,bcos the guy who was dating her is in doubt ,to claim the baby.

8 years 1 month ago

I’m 30 weeks pregnant due the 9th of june so according to doctors i’m pregnant for 40 weeks = 10 months. what i don’t understand is.. my last period was the 1st of sept till the 7th doctor said i got pregnant the 4th of sept? so i got pregnant while on my period.. i didn’t think this was possible? so i’m very confused.. can anyone help?? i did have sex on the 4th or late night on the 3th..

8 years 4 months ago

Ok so neyways I’m 7months in 8days can’t wait to meet my lil mann “). Nd yuh do qo up to 10months preqo. Btw; I also h8 how some qirls don’t understand when yur in love yuh don’t wanna ruin whatcha qot. She said she told him b4 he miqht not b tha father of tha baby but he blew it off like she neva said it. So therefore he did that cuz he wants that baby to b his dummy. Jessica keep ya head up mama. Nd forqet tha h8ters they only wanna see yuh fall.

8 years 5 months ago

can sexly conduct at the time of month of 8

8 years 5 months ago

Not sure why so many are stuck on figuring out the date of the last period. When an ultrasound is done, a doctor is able to tell what stage of development the fetus is and go from there.

8 years 7 months ago

Hi i took a home pregnancy test it came out positive. I had a feeling i was. I was feeling sick. I only had unprotected sex on 1 day which October 6th. I can’t remember when my period was in September. How am i going to now how far and when my due date is?

Jet Li
8 years 10 months ago

My wife just pass first trimester pregnancy.. We are calculating her due day is around January 5th.. Her LMP was April 1 BUT I think / SURE she got conception (late ovulation) just by the end of April.. It also happened to our first child.. so is there any chance her due date delay by 4 weeks?? say February 5th?? if let’s say by the time of conception/ovulation is like April 28th??

8 years 11 months ago

I really can’t remember when my last period was.All i know that it was in march,how can i really determinehow far along i am?

8 years 11 months ago

I’m still confused here. Tell me because i conceived on the 09 October 2009. How many weeks am i now and when am i due?

[…] 9 months is just a rounded number, its actually closer to 10 months but its easier to say 9 because its easier to seperate it into 3 trimesters this article explains it well…hpregnancy.asp […]

9 years 1 month ago

The women that lie to men about who is the father of their child, makes us Real Woman Look Bad! The child and father diserve to know the truth. Teach your child how to be a liar, great lesson! Why are you having children?

9 years 2 months ago
Jessica, I feel for you and your situation. I think if we all look at our lives we can all think of a time where we were just out of a relationship, very vulnerable and ended up doing something we regretted later on. However, in your situation now you have to wonder if that small slip in the summer resulted in a lifelong biologic conundrum with this deadbeat being the father. However, when I look at your dates I think there is a very good chance that your ex is the father even though there is still a chance of… Read more »
9 years 2 months ago

At 40 weeks you are 9 1/2 months pregnant you are not 10 months pregnant but you are in your 10th month.

9 years 4 months ago
essica I completely understand sweetheart and Valerie is right, don’t feel alone. I have today just discovered that the father of my eight and a half year old son is not infact his father at all…I am deeply shocked at this as I was ALWAYS 100% sure of his paternity. He questioned it when I took him to the CSA for financial support and he had a home test done. I have no proof he actually used his own DNA however so am currently sat here in a state of shock and confusion. I was with my son’s “father” for… Read more »
9 years 4 months ago

omg.. Jessica! I am in the Verrryy exact situation. And im due in march.

9 years 4 months ago
Jessica, I am in the same exact situation! I am now 13 weeks and I don’t remember my LMP and my ex thinks it’s his, except the other guy is there for me too which i’m lucky for that. I was with with my ex for 5 years and never got pregnant. Honestly if your ex really cares about you, he will stick with you and don’t worry if the other guy doesn’t. Guy # 2 has to send child support no matter what. Don’t worry if you feel alone cause there are hundreds of women in the same situation.… Read more »
9 years 4 months ago
I’m so confused about this whole thing. This is my first pregnancy and my doctor has ordered me a second ultrasound because I guess when she measured my belly, the measurement was larger than what it should be for the amount of weeks she had me down for. Anyways, I don’t want to be looked down on for this, but I don’t know who the father of my baby is. I had just gotten out of a long relationship, and felt alone, yet was still somewhat in the relationship…anyways…I was with my ex and another guy around the same time,… Read more »

[…] math. Fortunately, for me and lil’Lambert, I’m not quite this stupid. According to this site, if you strictly use the lunar calendar then you would divide the number of weeks you are pregnant […]

9 years 5 months ago

i say that there is ten months in a pregnancy because im one of those people that feels like ive been pregnant forever. im 37 weeks so i would say that im 9 months pregnant.

9 years 7 months ago

my wife is about ten months pregnant.
her doctor told her she should expect delivery on the 9th september 2009. but today is 17th september, 2009.
i want to find out if the baby stands out any complications,
or is there any risk to the unborn baby? and what should we do? is CS only the option. am worried

9 years 7 months ago

Thank You for this! me and my best friend have been bickering whether I am 9 months or 8 months pregnant. right now I am 36 weeks going on 37. I say either way it goes, its almost over! Hurray to the day of no more hip pain!!

9 years 9 months ago

Hi, my first day of my last period was May 8, how old is my pregnancy….? I’ve been doing the math but can’t come up with an exact countdown…. how many weeks am I, and months?

9 years 9 months ago

i have checked my EDD severally online and the dates keep changin,first it was 04march2010 and then 02 feb.2010 but my LMP is 28 may 2009 and i do not which date is correct.

9 years 10 months ago

i was born in 7 months…

9 years 11 months ago

yes, October sounds about right.
you must be due any day now!

9 years 11 months ago

is it possible that i might have conceived during october as that the only time i remember when i was on my periods????

9 years 11 months ago

i would also like to know how to calculate when i conceived as i dont even remember when was my last period as i never had normal periods every month..

10 years 1 month ago

I always thought that pregnancy was 10 months ๐Ÿ™

10 years 1 month ago

I am now 35 weeks pregnant. I have delayed conception by 3weeks otherwise i would be now 38 weeks pregnant. from starting i have doubt about my EDD. by my 1st sonography it says 21 may. i.e. i wil complete 40 weeks on 21 st may. and i alrady staretd my 36 th week. is it possible to expect baby less than 40 weeks?

10 years 4 months ago
The reason why, they whole 10 months come into play is if you take 40 and divide it into 4 you get ten.. okay.. if you say that pregnancy last only 9 months plus the extra 7 days from the LMP.. Then that would put you at 37 weeks, because at 36 divided into 4 is 9, and being 7 days extra from the LMP. Then that is considered 9.25 months.. so if your pregnancy goes for a whole 40 weeks then yes you are pregnant for 10 months do the math. Im pregnant and my dr told me that… Read more »
10 years 4 months ago

im 46 now, when mum was pregnant with me she was infact carrying twins but had a partial miscarraige and went on to carry me for 11 months

jordan d
10 years 4 months ago

How often do shorter pregnancy occur? For example an 8 month pregnancy? Are they really that uncommon?

Lisa Marie
10 years 4 months ago
I understand what there talking about what I don’t understand is the 2 weeks that they want to put ur pregnancy started even before you concieved. My first pregnancy doctors try to give me Sept. the 28 n 29 when my last men. was 12/22. okay well other doctors gave me oct 9. guess what I was lucky n had her on the 10. that is exactly 40 from when I conceived during the ovulation. whitch is 3 days after 14 days of your first day of your last period no matter how long your cycle is. Now this pregnancy… Read more »
10 years 6 months ago

Hi, my mother had a 10 month pregnancy, and I was not in the right position for the delivery and I was born with teeth (or at least one tooth) and hair… so I guess there really are 10 month pregnancies. What is strange is that there are not material about it.. I mean to know if there are consequences of it , etc mabye because there are always people, like you, denying the evident! I am 30 and my wisdom teeth never appeared

10 years 7 months ago

Natasha: It is not possible to determine a round about due date if you don’t know when your last period was. Also some women ovulate WAY before or WAY after others so they can’t use the due date calculators either. In your situation (and theirs) the only way to determine a round about due date is to have an ultrasound done before you are 12 weeks along… (ultrasounds done after that can be up to 2 weeks off).

10 years 7 months ago

i reall wish someone could explain this senario to me how would you determine a round about due date not knowing when your last period was???

10 years 7 months ago

what if you dont have regular periods and cannot fully determine when your last period was if you dont remember having one, how do you determine how far along you are on a due date caculator??

10 years 11 months ago

The article above is so educative and true. I want to thank the author for taking the time to clear the argument. And to ‘babiesonline’, u guys are great for the great fun and education site u put up here. Every expecting parents will love to come here and be educated. It’s my first child and I am really happy to come here and feel the joy of a dad-to-be knowing more about my coming baby. Thanks always

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