When gestational sac size is more than 25mm and no fetal pole or yolk sac then it may be a sign of missed abortion. But gsac getting as big as 89mm with no fetal pole or yolk sac is very unusual.
Possibly you may have a gsac elsewhere that is smaller in size with features of pregnancy.
Next Steps
1. Do 2
beta hcg blood tests 48hrs gap. the value should double (atleast 35%)
2.Repeat scan after 2 weeks
Health Tips
if you experience abdominal pain or bleeding visit your doctor immediately