Motion pictures that show the earliest beats of a baby's heart from inside a mother's womb are probably the most amazing sights to be seen on the CBS special, "The Body Human: The Red River," at 8 tonight on Channel 9.

What the narrator doesn't tell viewers is that this fetal photographic process presently can be used only inside the bodies of mothers whose pregnancies will be terminated. Thus, the life we see beginning in these films ended a short time later.

That program, superior to this one, will be repeated later in March on public TV stations.

All four cases studies shown in "Red River" are moving personal chronicles. It may be the most extreme invasion of privacy possible to photograph the open heart of a six-year-old girl in the operating room, but all the patients filmed gave their permission and the photography that results is sometimes spellbinding.

Where Suisz errs is in making his script a melodramatic encomium to the medical profession. It's like an antidote to "Coma." The narration is sprinkled with phrases like "the drama-filled world of medicine," "the rich and wonderful gift of life," "a bold, innovative strategy" and, "a sense of deep, unspoken dread."