Woodrow joined Southend in September and the striker has yet to score in nine appearances in League Two.
The 18-year-old did net a brace in 5-2 defeat by Dagenham & Redbridge in the Johnstone's Paint Trophy last month and Southend boss Phil Brown is happy to be keeping Woodrow.
Brown told the club's official website: "It's great news that Cauley will be here with us until the end of the campaign.
"He's worked extremely hard since joining on loan initially for a month and then a further month.
"As a young striker it's important to get games and goals. Cauley has got a couple in the cup and I'm sure when he does get that first league goal he'll kick on from there.
"Extending this until the end of the season means he can settle here, work hard and improve as a footballer with us."