The aim of health guidelines is to ensure consistency in the delivery of care to minimise health-related complications. However, even when good evidence is available, professionals do not necessarily implement it. Following a 2011 survey (Time 1) of staff in a tertiary maternity hospital, a number of service changes were implemented to facilitate best practice delivery of care to pregnant women regarding gestational weight gain (GWG). A (second) staff survey was then undertaken to re-assess staff knowledge, attitudes and behaviours around the management of GWG in our hospital. This cross-sectional, prospective online survey was distributed to staff in antenatal clinic. The survey assessed staff awareness of pregnancy-related weight complications, knowledge and application of specific guidelines, and a guideline adherence score was calculated. Sixty-nine staff (44.8% response rate) completed the 2014 (Time 2) survey. Just over half (51.9%) stated they were familiar with clinical guidelines regarding weight management in pregnancy. Guideline adherence ranged from 3.7 ± 1.9 to 11.3 ± 1.0 /15 across different professional groups; significant improvements with adherence by dietitians were noted over time. Despite minimal change over time in the overall adherence score, compliance with individual elements of the guideline recommendations comprising the adherence score differed. Improvements in staff practices and attitudes are apparent since the first survey. However, further improvements in guideline awareness and guideline elements are still required to improve the delivery of best practice antenatal GWG care.