Shares of business social network site LinkedIn have fallen sharply in after-hours trading after it reported its first quarter earnings.

The company also said it expected to make between $670m (£436m) and $675m in the three months to June, less than the $718m that had been expected.

It blamed the stronger US dollar and costs related to the purchase of the US online business Lynda.

LinkedIn announced it was buying the company for $1.5bn last month.

Chief financial officer Steve Sordello said he expected revenue contribution from the purchase to "normalise" in the second half of 2016.

Its New York listed stock was down as much as 25% to $188.20 in extended trading.

The disappointing forecasts came as the company reported that its net loss for the first quarter widened to $43m.

That compares to a loss of $13m for the first quarter of 2014.

However, revenue grew 35% in the period to $638m.

Chief executive Jeff Weiner described the quarter as "solid" and one in which the company "maintained steady growth".

• When investors buy and sell shares outside the regular opening hours of major exchanges
• It exists because big financial institutions want to trade large blocks of shares 24 hours a day
• Adopted in the 1990s by financial institutions and some rich investors; the growth of online trading led to ordinary investors being able to take part a few years later
• Riskier than trading during regular hours - trading volumes are lower and share prices can be more volatile, meaning the spreads between the buying and selling prices of shares can be wider
• With less information available it can be harder to work out what's behind some after-hours price movements, leaving small investors at a disadvantage
• But potential profits can be higher