HCG increasing only 73% Still viable pregnancy?

I'm approx 4 weeks 4 days. Not sure exactly when I ovulated, going off the 1st day of my last period. Had 1st HCG quant done Monday, results 157. Had the 2nd HCG quant done yesterday, results 273. Went up 73%. I've had an ectopic pregnancy in the past, but I don't remember my counts. I thought I'd already had a miscarriage when I was diagnosed w the ectopic and taken straight into surgery. 
So, my question: has anyone had their #'s increase similar to mine and go on to have a healthy pregnancy?