  We study combined effect of hydrostatic pressure and magnetic field on the
magnetization of La${_{0.5}}$Ca${_{0.5}}$MnO${_{3}}$. We do not observe any
significant effect of pressure on the paramagnetic to ferromagnetic transition.
However, pressure asymmetrically affects the thermal hysteresis across the
ferro-antiferromagnetic first-order transition, which has strong field
dependence. Though the supercooling (T*) and superheating (T**) temperatures
decrease and the value of magnetization at 5K (M$_{5K}$) increases with
pressure, T* and M$_{5K}$ shows abrupt changes in tiny pressure of 0.68kbar.
These anomalies enhance with field. In 7Tesla field, transition to
antiferromagnetic phase disappears in 0.68kbar and M$_{5K}$ show significant
increase. Thereafter, increase in pressure up to $\sim$10kbar has no noticeable
effect on the magnetization.
