There is nothing certain but uncertain - this applies to babies at weddings as well
In addition to your regular diaper bag, carry a few extra baby outfits, easy-to-eat foods & a pram
Have reasonable expectations - you may not be able to bring the house down with your late-night dancing skills
Carry the baby in a sling - she will be super comfortable and you can keep the pesky relatives from carrying her as well
Weddings are noisy - child-friendly ear/cotton plugs will protect your baby’s ears
Take regular breaks to hang out at a space away from the main event space - it will be a quieter place where the baby can be more comfortable
If you are breastfeeding, make sure you get plenty of rest throughout the ceremonies
Try and get a babysitter who can Netflix and chill in the hotel room while the baby sleeps
Sit in a place where you can duck out quickly if required without disturbing other people
