I’ve seen plenty like that. Pretty realistic too. Most pregnant people have perky nips like that
So, the main issue is the fact this is early in the pregnancy and the areolas extended instead of enlarging. "The areolas are the colored circles around the nipples. Over the course of the second and third trimesters, the areolas often become larger and darker." MedicalNewsToday
In addition, the actual breasts didn't grow larger, which is abnormal, "Going up a cup size or two is normal when pregnant, especially during a first pregnancy. This growth can begin early on in pregnancy and continue throughout." MedicalNewsToday
During pregnancy, major breast changes are usually due to producing colostrum then milk after baby birth. Colostrum is stored in the milk ducts, aka breast area
I've gone through hell finding these pictures (pregnancy fetishes are wild) but, the areolas usually get larger and darker without/with nipple extension
https://www.mangago.zone/home/album/363146/
Not a dig at the art style, I doubt I could do better. Just a nonharmful but odd detail to me. Also, I hate in omegaverse where they for some reason can't breastfeed even though real life males can. Its uncanny to have pregnancy in men but for some reason eliminating milk production. Glad they're (probably) not going that route due to breast changes
His newfound udders are bugging me. I've seen plenty of pregnant nipples...none like that...