Red book "months old" aren't 4 weeks?

[squizita]

Just wondering how they're calculated.

DD has some jabs tomorrow so I got out the red book. Looked at the growth charts idly as you do when your little pocket rocket only gains 1 lb a month no matter what and noticed that the month markers don't fall every 4 weeks. They're slightly longer.
Eg at 17 weeks I think of dd as 4 months old +, but in the red book she's only just getting there.

I suppose it only matters in terms of surveys. Even with weaning you'd be a week out max.

I can't tell from the graph exactly how many days in an nhs month.
Can anyone enlighten me?

4 weeks is 28 days- only one of the months of the year is that short, they're usually longer. Isn't it just that??

Well surely a month is a month I.e. 30 or 31 days as in the actual calendar month, not 4 weeks. I don't think the NHS counts months any differently to the rest of us

There is no difference between an NHS month and a real month. Four weeks is 28 days. A month is 30 or 31 (except February).

Only 1 month has 4 weeks in it so 4 weeks does not equal 1 month. I would say 17 weeks is closer to 4 months than 16 weeks. 26 weeks will be 6 months (half of 52 weeks)

I think also the confusion arises because in pregnancy it does tend to be a month is 4 weeks, then it shifts back to normal calendar months IYSWIM?

And everything non 'medical' seems to do this too. For example this website www.babycentre.co.uk/s1001653/3-month-old-fourth-week is typical of the books I have. Once you've done 3 months and 4 weeks, you're onto 4 months.
Although reassuringly it doesn't tell you your baby should be rolling from back to front at two-to-four months as Mumsnet's development guide does. I had to double check that one IRL and was much relieved to find that it wasn't the norm!!

I take months as from his calendar birth, so the 19th of the month I count him as x months old. I don't really think of him as a certain amount of weeks now ( he's just 5 months) (actually realised I don't know how many weeks today ) because by now changes are less sudden and stretched out iyswim? So a 4 weeks baby is very different to an 8 week baby, but any changes now don't need to be pinpointed so exactly (developmental changes as you mention could happen some time within 4 months or so, not within a couple of weeks). Growth as well, DS put on over 3 pounds in his 3rd month and only 1 pound In His 4th month, this is not an issue on the charts now as it may have been when he was 4 weeks old. I think as your baby gets older, you don't need to be so exact as development is so different in older babies. I'm going by his calendar 6 month 'birthday' for weaning, but I know if I gave him food a week before it wouldn't be a problem.

Even in pregnancy 4 weeks isn't calculated as a month. A pregnancy is 9 months or 40 weeks. If 4 weeks was counted as a month they'd say you were pregnant for 10 months. Months in pregnancy/early years are just normal calendar months, I.e 30 or 31 days, unless it is February.

DD was born on the 13th of a month. I said she was 1 month old on the 13th of the following month, not 4 weeks after she was born.

That's odd ... my consultants seemed to go by 4 weeks (and I was in there weekly! ).

A month by any other name is still a month.

Sorry op, i dont understand the question.

I'm fairly sure noone makes a direct equivalence between 4 weeks and 1 month. Perhaps roughly, if they were talking casually about periods of time. But medical people don't have a different definition of 'month' to the rest of us.

It's just my hcp seem to measure a month differently to everyone else!

Everything is (and was in pregnancy) done on 4 weeks not 30/31 days.
I guess it's easier to schedule things? Though it means the date they suggested it was ok to wean is slightly out.

I had exactly this conversation with someone on FB the other day who said she was going to start weaning because her baby was nearly six months. Turned out she thought 24w was 6m and therefore 22w was "nearly six months".

A month has 30.4 days, on average. The NHS tends to use weeks as more accurate, since every week has seven days.

Cross posted.

They recommend weaning at 17-26w or 4-6m. They're the same. What HCPs have you been talking to?

This reminds me of the "How many days are there in a week?" bodybuilding thread that went viral last week.

MrsHathaway Phew! I thought I was the only person for whom this confusion arose!!
Honestly I have a normal awareness of how calendars work - I was literally going with what my experience at the local clinic was.
As it seems it runs month to month like birthdays I will go with that re weaning.

But the PP implying I hadn't been told 4 weeks = a month had me a bit unless they were in my clinic every ante and post natal visit.

St Marys consultant led ante natal.
North West London HV team at a local clinic.
Honestly they measured it like this with me. I'm perfectly numerate - I'm just used to it beibg 4 weeks! It could of course be because clinic runs the same day every week - they don't want to confuse people so approximate. Silly me thinking that was an official thing!

Pregnancy is always calculated in weeks, not months. HCP will always talk in weeks. Is that what's confused you OP? Now you've had your baby they will measure time in months not weeks.

52 weeks in a year, divided by 4 = 13 months. Now unless you're aware of a new month...

This greatly annoying me in pregnancy too. On a previous board folk would insist that they were pregnant for 10 months due to the 4 week month.

I don't understand how they say you're pregnant for 40 weeks from the first day of your last period. Really you're only actually pregnant for 38 weeks if you go to your due date? I'll stop over thinking this now!!

Either way - 52/12 = 4.33. weeks in a month

I don't understand why you think they use 4w and 1m interchangeably, eg "See you in a month"

I went to 40+6 twice. I did not go into an eleventh month of pregnancy although it felt like it.

Nothe yes that last period thing is especially annoying if you have short or long cycles! No one could figure out my actual due date ... and I didn't want an unnecessary induction due to miscalculation.

Thank goodness for my many many scans! At least it got them to agree I was due when I said I was!

Mrs because it's not just appointments. They talk about jabs and weaning using 4 weeks = a month. I just realised this means her jabs started slightly early!

I never questioned it.

A month is 4.3 weeks. People often use "week" and "month" interchangeably because they're close but actually there's half a week in it (except February).

It shouldn't be confusing. There are 52 weeks in a year and 12 months. So 6 months is 26 weeks. If you want to interchange months and weeks for measuring pregnancy and baby age it's closer to say

3 months = 13 weeks
4 months = 17 weeks
5 months = 22 weeks
6 months = 26 weeks

Just to REPEAT ... I'm not "confused" so much as used to my clinic booking/advising according to a month being 4 Friday sessions. This DID include things like weaning I'd be doing at home. I now realise they may have over simplified this for whatever reason.

However you will have to take my word for it.
Bear in mind this HV also plotted my DD'S weight incorrectly and her boss had to change it.
So maybe I was a fool to never question her dates!

Here, most things are done in weeks. Pregnancy is between 37 and 42 weeks. Scans are at 12 weeks and 20 weeks approximately. Routine appointments are done at 28, 32 34, 36 and 38 (or whatever it was, I'm old and forgetful). Jabs are done at 8, 12 and 16 weeks. Weaning is at 26 weeks.

I think people do use months as shorthand sometimes but for calculating important stuff like plotting centiles or scheduling jabs or planning weaning, it's done in weeks.

...as in bang on 16 weeks they CALLED her 4 months ... she used the words 4 months. I didn't query this, why should I?

If a pregnancy month was 4 weeks, then pregnancy would only be 36 weeks long. A month is more than 4 weeks!