Hi!The mass which had been detected during your antenatal ultrasonography
seems to a benign lesion ,most probably a fibroid
,as it has been detected accidentally without any previous history of signs and symptoms.Most of the pregnant women will not suffer from serious complications due to these fibroids except for few in whom the chances of miscarriage
or preterm labour can be there if this fibroid grows in size.But in your case as it has been mentioned that these fibroids are calcified, so dont panic as calcified fibroids are far more quieter than normal fibroids.To be on the safer side keep watching for any light spotting or lower abdominal pain
and also monitor this mass by antenatal ultrasonography .Take care!