Rep. Carol Shea-Porter’s re-election prospects have slightly improved, but the Granite State’s two Congressional seats — both currently held by Democrats — are still largely up for grabs.

The latest poll by the University of New Hampshire Survey Center showed that Shea-Porter had taken a “small to moderate lead” over prospective Republican challengers in the 1st district.

That’s a marked improvement; the Democrat trailed all four Republican hopefuls in February and April surveys.

UNH pollster Andy Smith explained that Shea-Porter’s improvement is “due to her improved favorability ratings and her opponents’ inability to raise their profiles during the summer.”

But, Smith adds, “It is important to point out that Shea-Porter does not break 50 percent against any of her challengers, a critical indicator of weakness for a Congressional incumbent.”

Shea-Porter led former Manchester Mayor Frank Guinta, her best-known GOP challenger, 44 percent to 39 percent, with 16 percent of those surveyed undecided.

In New Hampshire’s 2nd district, former Rep. Charlie Bass (R) is leading the race to replace Democratic Rep. Paul Hodes, who’s running for Senate.

In a hypothetical matchup between Bass and Democrat Katrina Swett — a rematch of their 2002 contest — Bass led 47 percent to 30 percent, and 21 percent were undecided. That’s the same margin the poll found in April.

Swett must survive a competitive primary against Ann McLane Kuster to reach the general election. She finished the last quarter with $745,000 in cash on hand, compared with Swett’s $1.2 million.

In a hypothetical matchup between Bass and Kuster, Bass led 47 percent to 29 percent, with 23 percent undecided.

Despite the lead, Smith notes that Bass has liabilities. His unfavorable ratings have jumped sharply in the 2nd district since his entry into the race.

Thirty-four percent have a favorable opinion of Bass, 34 percent have an unfavorable opinion of him and 33 percent are neutral or don’t know enough about him to say. Those numbers are down sharply from February.

UNH surveyed 504 New Hampshire adults from July 19-27. The margin of error was 4 points for statewide questions but 6 points for smaller samples of voters in the 1st and 2nd districts.