According to the most popular view, the Muslims numbered seventy-five; seventy-three men and two women, who pledged their allegiance at the blessed hands of Rasulullah (sallallahu ‘alaihi wasallam) in the very same valley where the first group had pledged their allegiance.
This second pledge is referred to Bay’at-ul-Aqabah Thaaniyah (the second pledge of allegiance).
Allaamah Ibnul Jowzi (rahimahullah) says that the people who pledged their allegiance on this occasion numbered a few more than seventy-five.
(Extracted from Seeratul Mustafa 1/337)