Hello thank you for your query. The medications you are taking are appropriate, however I hope there was some past or present high risk factor in the pregnancy as you are being high doses of B HCG and progesterone to support the pregnancy. The anechoic area you mention could be a corpus luteal cyst which is common in pregnancy. Other ovarian cysts also are likely, and for that I need further details of the ultrasound report. Most ovarian cysts, particularly corpus luteal cysts , are likely to regress as the pregnancy advances, however if it does not, there are chances of torsion ( twisting ), infection etc. Please get back with detailed information for further consultation. Take care.