"Thanks for the kind offer, we would like to spend our first Christmas together as a new family given how soon after birth it will be, so we won't be able to come on Christmas day, maybe we could arrange something for the week between Christmas and new year?"
I think the suggestions are spot on, just wanted to say I really feel your pain - I'm not worried about the birth at all but Christmas and new year plans are keeping me up at night!
We’ve had to decline multiple times from different family wanting us to spend Christmas with them. We just say it’s easier for us to spend it round ours and this way we can stay in pjs (most likely still going to be in nappies myself.. I don’t want to spend the night round someone else’s and have to pack the car for 2 kids 2 adults and dog)
You could also mention that the baby won’t have had its jabs yet, and are worried about it being round the kids as they are notorious for picking up bugs from school at this time of year, or say you had mentioned it in passing to the midwife and they advised against the long travel with such a small baby. Maybe invite them to you on boxing day or christmas eve for a meal instead x
The travelling alone would be my excuse. We were invited to my sisters, bsby will be 4wks and it's 40 min in car and I still said no. It's a horrendous journey if baby screamed whole time.
It’d surprise me if family members would still be expecting attendance given our newborns?! Like ofc they’ll still extend an invite, my in-laws did, but in a very casual “are you guys coming this year, no pressure, we’d just like to know” way. Which surely is how it should be for this year? Our babies will only be around 6 weeks old, low immunity, no vaccines yet, Mammas still potentially recovering, parents not sleeping, and generally getting used to a whole new lifestyle lol. Also, it’s winter. If anyone in that household has even the slightest symptoms of a cold, then hell no am I going with my newborn! After politely explaining why you can’t go, they really shouldn’t have an issue with it. If they do, that seems like more of a them problem, not a you problem?
Get your partner to do it so you’re not to blame, but just say you’re tired, baby can only be in a car seat for 30 minutes at a time and then requires a pro longed break where they are led flat so that’ll make the journey even longer and with how tiring having a new born is then a pro longed drive would be too much for you both, that if the baby was older you’d of loved to but hopefully you can all do something together soon xx