Hello. Thank you for contacting HCM. I have gone trough your question and I understand your concern. I will try my best to give you a satisfactory question. According to my understanding you have two questions....one about the difference in LMP and ultrasound and the second one about your pregnancy s safety. As for your first question the date of last menstrual period is a calculated guess based on the woman s reproductive cycle to find out the duration of a pregnancy whereas the ultrasound findings are based on the measurements of the fetus. the ultrasound findings are usually more accurate in terms of determining the age and growth of the fetus. The difference in these two occurs because you may have conceived later on in your reproductive cycle rather than right after your last periods. now coming to the second question. Sub chorionic hemorrhage may lead to spontaneous abortions in some case that is why a follow up ultrasound is recommended to keep a close eye on your pregnancy. Meanwhile, I would suggest you avoid any undue stress and take good care of your self. I hope this answers your query. Please feel free to contact HCM if you have any query. Wishing you and your baby good health.