Miami-Dade County Commissioners put a swift halt to plans to close the obstetrics unit at Jackson South Community Hospital on Thursday, while berating the Public Health Trust that runs Jackson for its decision last week to close the money-losing center. The county commission's move to overrule the shuttering of the under-used obstetrics facility illustrates the tough challenges the Public Health Trust faces in finding ways to reverse losses at Jackson Memorial Hospital while preserving its mission of providing vital public health services. The Public Health Trust voted to close the obstetrics unit at Jackson South because it is projected to lose $2.57 million this year and averages only eight patients daily. The trust said those pregnant women would be welcome at Jackson Memorial, 21 miles away.