One possibility is that your pregnancy is simply not far enough along to see a fetal pole
on an ultrasound. The fetal pole becomes visible in a transvaginal ultrasound
somewhere between 5 to 6 weeks of gestational age
If you incorrectly remembered your last menstrual period date, that can change the expected findings on an ultrasound , or if you have an irregular cycle and do not ovulate two weeks after the start of your last menstrual period, your pregnancy may not technically be "five or six weeks along" even if it has been five or six weeks since your last menstrual period. These can lead to non visualization of fetal pole.
In such a case you just have to wait and get a repeat ultrasound after a week or two.
The other possibility is miscarriage
due to blighted ovum
. A blighted ovum is a condition where gestational sac
develops but the baby never develops enough to become visible on ultrasound.
When a woman becomes pregnant, the fertilized egg attaches to the uterine wall. At about five to six weeks of pregnancy, an embryo should be present. At about this time, the gestational sac where the fetus develops is about 18 millimeters wide. With a blighted ovum, though, the pregnancy sac forms and grows, but the embryo does not develop. That's why a blighted ovum is also called an anembryonic pregnancy.
In such a condition pregnancy usually aborts.
In your case you also have perigestational bleed which can further support the fact of miscarriage.
But if you have no vaginal bleeding and pain, you can wait. There is no harm in waiting.
You can get a repeat ultrasound after a week. If the repeat scan also shows no growth of sac or fetal pole, then it suggests that the pregnancy is not viable.
Meanwhile you can continue taking Folic acid tablet
. Take adequate bed rest and avoid intercourse.
All the best.