Post # 1
Darling Husband and I are so confused with this pregnancy calculation thing.
The first day of my last menstrual period was 20 June. So logically, it would be like this:
20 June: Beginning week 1 of pregnancy: 0 weeks pregnant
27 June: Beginning week 2 of pregnancy: 1 week pregnant
4 July: Beginning week 3 of pregnancy: 2 weeks pregnant (= ovulation and conception)
11 July: Beginning week 4 of pregnancy: 3 weeks pregnant
18 July: Beginning week 5 of pregnancy: 4 weeks pregnant (21 July BFP)
25 July: Beginning week 6 of pregnancy: 5 weeks pregnant
1 Aug: Beginning week 7 of pregnancy: 6 weeks pregnant
8 Aug: Beginning week 8 of pregnancy: 7 weeks pregnant
But, this is calculated with a regular 28 day cycle, each week starting on Monday (20 June was a Monday, and the first day of my last period). But, I have a 30 day cycle. So should I calculate every week to start on Wednesday? So week 2, starting on 29 June, iso 27 June?
Today is 25 July, so I am either 5 weeks pregnant, start of week 6. Or… am I 4W5D pregnant and will I be 5 weeks on Wednesday 27th July?
I know there are tools to calculate this, which I have used and I know my estimated due date is March 29th, but I would really rather understand it myself. The whole Week X and X many weeks is so confusing to me especially with my slightly longer cycle!
Thanks if someone can explain this to me!
Post # 2
Your doctors will most likely use your last period as your 0 weeks pregnant / starting week 1, so I would use Monday as your start date until you are told differently by a doctor 🙂
Its like birthdays… I am 34 years old but am in my 35th year of life. Most people just refer to the week that has past as how pregnant they are, not the week they are currently in.
Post # 3
The longer cycle won’t make a difference unless you ovulate 2 days later as well ie 16 rather than 14 days after the first day of your lmp. Unless you know when you ovulated there’s no point adjusting dates.even if you do, fertilisation could have occurred up to 5days later, so it still may not be accurate. You’ll get accurate dates at your dating scan around the 12 week mark
Post # 4
Interesting…so my last period was June 30 but I conceived July 14. My due date is April 6.
I was counting myself as 1 week, but I’m really like 3 weeks???? I need to call and schedule appt with ob/gyn anyhow…guess they’ll tell me too. Is first appointment 6 weeks or 8 weeks?
I’m going to email my fam dr bc I have a couple questions anyhow and see what he says regarding how far along I am.
Post # 6
Doctor’s use LMP because it is the easiest way to date a pregnancy without doing an ultrasound. That assumes you ovulate on day 14, and doesn’t really matter how long your cycle is (whether it is 26 days, 28 days, or 30 days). If you ovulate on another day, it is off that # of days in either direction.
No point in trying to adjust dates unless you know 100% (via charting/temping) the exact day you ovulated. You’ll go by the first day of your last menstrual period. So you are 5 weeks pregnant today.
Post # 7
summerbride2016 : april 6 is correct and you would be 3w4days. If you want to count O day as a starting point, count 2 weeks back from O day. O day is 2 weeks pregnant. Yes, you are now technically “pregnant” before you’re actually pregnant. They are going by the life of the egg, which “begins” 2 weeks before O because that is when it starts developing (assuming you O CD 14) on CD1
Let’s say I was temping and ovulated for sure on day 17. To be completely accurate I would say the first date of my “LMP” was actually CD4 instead of CD1. As far as dating purposes with an OB is concerned. Your ultrasound would/should match “LMP” being CD4.
But let’s be real, most women do not know for sure when they ovulated so all the doctor’s can do is do a best guess by using LMP as a starting point.
Post # 8
kes18 : Oh! Thank you, that makes so much sense!
Post # 9
kes18 : Westwood : verysoonnow : CityBearBride : thanks for the explanation, girls! I am still a bit confused about the 30 day cycle but for now I guess I will just accept that I am five weeks, counting from a regular cycle. My doctor will adjust if necessary. It’s not an exact science when the baby will come anyway, so in the end two days more or less won’t matter that much anyway. So then today I am 5W1D!