HCG Levels & Early Pregnancy: Understanding Normal Progression

Question
I am 22 years old and this is my very first pregnancy.  My last period started on Jan 13.  I tested positive at home on 02/14 and my hcg level was 71 on 02/15.  I tested again on 02/20 and it only went up to 157.  Obviously these numbers didn't double every 2-3 days like I've read they are suppose to.  I also had cervical mucus with a very light brown tinge to it for 4 days (02/16 - 02/19).  This would only happen one time at night and only when I wiped.  Does the slow rising beta sound like a problem to you? I am really worried and praying that everything will be alright. Thanks for any information.

Answer
Although we used to be reassured if HCG values doubled every 48 hours, it is not written in stone and we would be equally reassured if there was a 50% rise every 48 hours. Your levels appear a bit low four weeks after the start of your period. After 6 weeks (from the first day of your last period) you should see a fetus and a fetal heartbeat. If you do, it is a good sign. If you do not see a fetus or a heartbeat at 6 weeks, it is not promising and may indicate a nonviable pregnancy. Don't lose hope. Good luck.