The Hammers, meanwhile, chalked up only their second away win of the season as a demoralised Birmingham slumped deeper into the relegation dogfight.
There is little sign of any respite for the beleaguered Birmingham boss, Steve Bruce, who is at his wit's end attempting to end the Midlands club's harrowing run.
Yet again he suffered the cruel blow of early injuries to Mario Melchiot and Muzzy Izzet, two players who have only just resumed playing after long-term absences.
With only one point from their previous five home games it was a demanding situation for Birmingham and they suffered an early setback when Melchiot was injured in only the fourth minute.
Melchiot had only returned to first-team action in the League Cup game at Millwall after missing the previous eight matches in Birmingham's slump into the bottom three.
But Birmingham were only downhearted for a short period as they stormed into a shock 11th minute lead when Emile Heskey displayed a rare bit of opportunism.
The deficiency in Birmingham's home performances this season has been the lack of a goalscorer, but all this was brushed aside when West Ham were punished for some indifferent play by Yossi Benayoun.
David Dunn gained possession on the halfway line and quickly despatched a long pass into the path of the isolated Heskey who smartly cut into the penalty area. As Ray Carroll attempted to narrow the angle, Heskey confidently slipped a low cross shot into the empty net.
But Izzet then become the second casualty in the 20th minute when he stretched going into a tackle and sustained a leg injury in only his fourth appearance of the season.
In the circumstances it was hardly surprising that West Ham had underestimated Birmingham, but they did so at their cost in the opening spell. They had to lift their game and slowly settled down to produce some skilful play.
Only a brilliant save by Nico Vaesen prevented Marlon Harewood from grabbing an equaliser. The Birmingham keeper had to fling himself to his right to keep out the ball which was about to enter the top corner of the net.
But it was only a taste of what was in store for a Birmingham defence which lost its shape and discipline in the face of ever-increasing attacks in which Harewood was undoubtedly the major threat.
The Hammers' skill earned them their 35th minute equaliser when Birmingham's reorganised defence was in a complete tangle as Bobby Zamora determinedly worked his way through three defenders before slipping the ball through the legs of Vaesen from close range.
Any confidence which Birmingham had following Heskey's goal evaporated in the closing stages of the first half when the ever dangerous Harewood notched his sixth goal of the season in the 43rd minute.
The ball appeared to have crossed the line before Matthew Etherington crossed the ball which was flicked on by Benayoun to the lurking Harewood to lash his shot past Vaesen.
Birmingham strived for the equaliser, but the harder they tried to get on level terms the more they became frustrated by their lack of success.
On-loan Nicky Butt lashed a shot over the bar, while Dunn watched a low drive go just wide.
Later Matthew Upson lunged in to hammer his effort over the bar from close range and then Heskey shot straight at Carroll.
It was one of those games for a Birmingham side lacking serious finishing power.