Belly (ac) measuring 1 percentile

At 33w5d ac measuring 1 percentile, overall growth is 14 percentile. Ac is dropping continuously. 20 week -48 percentile, 24 week- 21 percentile, 28 week-18 percentile, 31 week - 5 percentile rechecked after 5 minutes 15 percentile. And today it was 1 percentile, another appointment with mfm scheduled next week.