12w ultrasound! Any gender guesses?? (Please!) :D

Sometimes ultrasound scans come out looking so weird! Lol This was my 12w scan at my high risk doctor. Any guesses on gender based on nub theory/skull theory/any other theories? We lost our daughter at 18 weeks due to incompetent cervix (cerclage surgery set for next week!) and we have 2 boys. Either way, I'm just hoping for a healthy baby! Heart rate stays between 158-162. Not sure if that matters, but I would love to hear some guesses for our little rainbow baby! :)