The funding level of the 5,945 schemes in the Pension Protection Fund (PPF) 7800 index improved slightly to 81% by the end of March.
This was against a backdrop of rising equity markets after deficits increased in February amid market volatility and falling gilt yields.
The lifeboat fund estimates the total deficit to have fallen from £322.8bn at the end of February to £302.1bn at the end of March, although it is a worse position than a year ago when the deficit was £244.2bn.
The funding ratio increased over the month from 79.8% to 81.0% at the end of March, yet it is still below the 84.2% recorded 12 months ago.
Total scheme assets increased by 1.2% to £1.3trn over the month, which was driven by the FTSE All-Share Index rising by 1.5%. However the value of scheme assets has decreased by 0.8% from a year ago.
Total liabilities fell by 0.3% over the month to £1.6trn but were 3.1% higher than at the end of March 2015.
The PPF's update said conventional 15-year gilt yields rose by 6 basis points (bps) while index-linked 15-year gilt yields fell by 3bps.
There were 4,891 schemes in deficit and 1,054 schemes in surplus.
BlackRock head of strategic clients for UK institutional business Andy Tunningley said March was a "positive month for pension funding" as assets benefitted from positive equity and credit returns.
He added: "Though March was generally positive for markets as central bank action, positive economic data and rising oil prices bolstered investor sentiment, clouds remain on the horizon - most noticeably the prospect of market volatility in the event of a ‘Brexit', which extended Sterling's weakening against the Euro in March.
"Brexit risk, coupled with the current low growth environment, continues to exert pressure on UK corporate balance sheets, increasing covenant risk for poorly managed schemes."
He said risk management should remain high in the minds of trustees as heightened volatility in the run-up to the 23 June EU referendum is expected.
He also pointed out that despite the PPF index improving over the quarter it is likely that buyout costs would have risen given the falls in corporate bond yields over the month.
"We see value in hedging inflation at current levels, and in recent months have added inflation positioning opportunistically to our actively-managed LDI accounts. Increases in inflation expectations such as those seen in March re-emphasise the importance of having liability-driven investment programmes in place to enable timely de-risking."
JLT Employee Benefits' research in March revealed the shortfall of all private sector DB schemes has risen from £425bn to £800bn in nine years despite employers trying to plug the gap.
Aviva Life & Pensions has concluded an £875m buy-in with its own staff pension scheme, following on from a similar transaction last year.
Nearly every trustee is confident of the next stage in their scheme’s strategy, despite almost an equal number being forced to consider replacing plans within the prior 12 months, according to research by Barnett Waddingham.
Companies could be overstating their pension liabilities by up to £60bn due to their life expectancy assumptions, according to XPS Pensions Group.
Just Group has completed a £74m pensioner buy-in with the UK pension scheme of a US-listed engineering business.
Defined benefit (DB) schemes that provide GMPs must revisit and, where necessary, top-up historic cash equivalent transfer values (CETVs) that have been calculated on an unequal basis, a landmark court judgment said last week.