The results are likely to be seen as a welcome recovery after a surprise sharp slump in March.
In total 1,771 agreements were completed in April worth £83m.
The market maintained its strong annual growth, with value of business completed up 11% and the number of deals up 9% in the 12 months to April.
Overall, £1.025bn of second charge mortgages were completed in the previous 12 months in 22,145 deals.
Finance & Leasing Association head of consumer and mortgage finance Fiona Hoyle said: “In the three months to April 2018, the number of new second charge mortgages was 5,339, unchanged on the same period in 2017.”