According to Official Guinness Records,
The fastest half marathon pushing a pram (female) is 1 hr 27 min 34 sec and was achieved by Lindsy James (UK), at the Ramathon, in Derby, UK, on 5 June 2016 Lindsy attempted the run with her son Archie in memory of her mother. She raised funds for MacMillan Cancer Support and Rotherham Hospice during her run.
For a complete list of 2016 records, please visit 2016 Guinness Records in United Kingdom.