(Reuters) - United Continental Holdings Inc <UAL.N> said on Wednesday it had advanced the retirement of 747s from its service to the fourth quarter of this year from end-2018.

United will replace the Boeing 747 fleet, which it has been flying since 1970, with other fuel-efficient, cost-effective and widebody aircraft, Scott Kirby, president, United Airlines, wrote in a blog. http://bit.ly/2iGGpTH

The No.3 U.S. airline by passenger traffic operated 22 747-400 owned and leased aircraft of its total 715 mainline fleet as of Dec. 31, 2015.

Boeing Co <BA.N> said in July it would consider ending production of 747s as it faced falling orders and pricing pressure.

The aircraft maker delivered a total nine 747s in 2016, half the deliveries in 2015.

(Reporting by Rachit Vats in Bengaluru; Editing by Sriraj Kalluvila)