Aizen’s first pregnancy came as a surprise for most, simply because his behavior barely changed, only becoming slightly more clingy and affectionate while also becoming harder to find, and no one realized until Shinji had the misfortune of stumbling across him just before he went into labor. He’s secretly thankful both Ichigo and Grimmjow were there because he was silently screaming the entire time. He’s also not thankful because they refused to let him leave the den to get the vet, it wasn’t until they sent someone to look for him that he was able to leave.
At least the pups were cute, even if the three hybrids had taught them to call him mom.