3 hour gtt results

i initially failed my 1 hour with 151, so i had to the 3 hour and these are the results. i was 16 weeks the day they did this test. i was curious as to why my second hour dropped slowly compared to one hour. did anyone get any similar results? should i be concerned. i will again get tested around 24-28 weeks.

Fasting: 78 (70-99) 1 hour: 155 (65-179) 2 hour: 150 (65-154) 3 hour: 99 (65-139)