@Brittney she’s had a couple like it since Saturday on and off. Does seem to be uncomfortable and strains before pooing even though she’s not constipated!
That's completely normal for babies especially newborns. Their digestive systems are maturing and they'll grunt and cry because that's the only way they know how to use their muscles until they are a bit older. My 8 week old son's face gets so red and he grunts and sometimes cries when passing a poo.
I believe with a MPA the blood would be darker. That's light so maybe your little one just had trouble passing that stool because red blood usually indicates it's from the lower gut. Does your little one have any other symptoms?