HCG level low at 15 weeks


I’m 15 weeks pregnant. Yesterday I got blood work done and the doctor said it was kind of low for being 15 weeks. It was 49,000 I’ve had two dating ultrasounds and they both said the exact same due date. Should I be concerned? Is this normal? I’m considered a high risk so I’m super nervous. I go for another ultrasound to check on baby on Tuesday.