Is a second 'Aqiqah required for the first fetus who died after one 'Aqiqah had already been slaughtered for him, or is one 'Aqiqah sufficient?

Aqiqah is recommended for the first and second child according to some scholars. One sheep is sufficient for a male, though it is better to sacrifice two. It is preferable to sacrifice two sheep for each son, but if one is sacrificed for each, it will suffice.