U.S. job growth fell to an 18-month low in March, according to a Wednesday report from ADP and Moody’s Analytics. Private payrolls increased by 129,000 in March, missing the 173,000 economists expected.

"The job market is weakening, with employment gains slowing significantly across most industries and company sizes," said Moody's Mark Zandi in a statement.

The bottom line: The ADP jobs report is seen as an important precursor to Friday's official government jobs report. The numbers don't bode well for those fearing that the booming jobs market is slowing down — especially after February's dismal report that showed only 20,000 jobs were added to the U.S. economy.

Go deeper: U.S. adds just 20,000 jobs in February