Due date help please

[FluffyPurpleSlippers]

Hello,

Recently found out we are expecting dc2. I’ve been using the Femometer app for around 6 months and have 4-6 week cycles with an average of around 40 days.

The first day of my last period was 24/05

Femometer says I’m 6 weeks +

Rest of internet with 40 day cycle suggests 4 +

As I’d like to get a reassurance scan before I get into the booking in and blood test stuff, I’m trying to work out which is most likely.

Can anyone share any wisdom?

I wouldn't bother stressing. Your booking in midwife will tell you the date she thinks, then your scan will probably move it around some more, and they're probably both wrong anyway because let's face it, everyone is so different physically that all projections are based on averages and very few people give birth on the due date anyway! Medical professionals moved my date forward 10 days from my own calculations (based on knowing exactly when conception was). I had an ELCS so cannot comment on when she would have come naturally, but I do think she was younger than they thought when she came out.

It's all guesswork! You can conceive days after ovulation so even knowing that does give you a super accurate date. If you are wanting a reassurance scan I would probably either go with a date in the middle of the two or if you can wait assume the smallest gestation then you are more likely to pick a date where it's likely the scan will show you anything reassuring.

Your midwife will go by the first day of LMP for the first trimester then you'll get an official due date based on the actual measurements at your dating scan.
The official EDD will probably be closer to when you actually ovulated.
The LMP date is based on an average 28 day cycle so, since you have longer cycles, it probably won't be that accurate for you.

On terms of scans, I would go by the lower gestation. It's better to be further on than you thought than further behind with potentially nothing to see on the scan.

Thank you for the replies. I’ll be smallest gestation 8 weeks by the end of July so I’ll plan for then.
Presumably it’s still simple enough to get a booking in. Last time I just wandered in and made a booking at the desk... not anymore!