Fetal heart beat is usually seen by 6weeks in transabdominal scan and 5weeks by transvaginal scan. But its not necessary as sometimes The heartbeat may not be detected for reasons that include: tipped uterus, larger abdomen, or inaccurate dating with last menstrual period. Concern typically develops if there is no fetal heart activity in an embryo with a crown-rump length greater than 5mm. As you said your scan shows a yolksac and fetal pole
which are good signs and you can still wait for the heart rate
to appear. Get an ultrasound
repeated after a week in which size of crl can be compared and also heartbeat can be checked. Sometimes dates are miscalculated just how far along you are, which can lead to expectation of heart beat very early.
But one thing which is alerting is you had vaginal bleeding. It can be an indication that your pregnancy
might be heading to abortion
and can be related to no visualization of fetal heart beat. Still you should wait for a week or two, sometimes bleeding stops and heart beat appears. Susten is a progesterone
, there are still studies going on to prove its efficacy in withholding an abortion process. So not all doctors reccomend it but still theres no harm taking.
Also avoid intercourse, heavy work, travelling.Take adequate rest and nutrition and do continue your folic acid