Spotting after +ve Beta HCG test. Above?

We are trying for pregnancy under doctor consultation. Wife's last periods was on 17th Feb which lasted 6 days. As per advice we were to try from 1st Mar, i.e. Day 13 to 8th Mar i.e., Day 20 on alternate days. Doctor had prescribed my wife Letroz 2.5 from day 2 to day 5 of periods, All 9 tablet once daily, Met PCO Care twice daily, and Dubagest SR 200 from Day 16 to Day 25 of periods, twice daily. We tried from 24th Feb upto 13th Mar, mostly on alternate days, sometimes 2 consecutive days followed by 2 day gap. On 18th Mar my wife noticed some spotting which resolved by evening, after which we consulted our doctor on 19th. As advised, we took a beta HCG test on 20th. The result came to be 44.1, indicating three weeks LMP (Range 5-50 on report). Consulted doctor on 24th March again and she says this value is too low. Is this value abnormally on lower side with the series of events that I have stated above? On 24th & 25th Mar, my wife had some spotting again with on and off mild cramps.