Advertising and media investment management climbed six per cent, consumer insight 3.2 per cent and branding, healthcare and specialist communications 10.6 per cent.
WPP commented that the PR market had been particularly difficult in North America, Western Europe and Asia Pacific, but the UK and Latin America had been stronger.
Its first quarter troubles follow a fall in annual headline PR profits last year from £142.9m in 2011 to £136.4m and a one per cent drop in like-for-like revenues.
The group, which is led by chief executive Sir Martin Sorrell, houses agencies including Burson-Marsteller, Cohn & Wolfe, Hill+Knowlton Strategies, Ogilvy Public Relations, Penn Schoen & Berland and RLM Finsbury.
Other large marketing services groups have reported better performances in the sector in the same quarter.
Weber Shandwick owner Interpublic Group showed growth of four per cent and Fleishman-Hillard owner Omnicom reported a 1.9 per cent rise.