Boroden looks at past swings of a given stock or index and then filters them through Fibonacci ratios. These are a series of numbers discovered by medieval mathematician Leonardo Fibonacci, who found that certain numbers repeat over and over again in nature. The same patterns are found in snail shells, flowers and the stock market.
Time cycles found in the weekly chart of the Dow industrials caused Boroden to worry that the recent rally could be running out of steam. Whenever she sees several time cycles coming together at the same time that could mean there is a reversal in sight.
Boroden spotted eight different Fibonacci time cycles in the Dow, with seven of them coming due next week, and one coming due this week.
Not surprisingly, they coincide with Donald Trump's inauguration.
This kind of a setup usually leads to a market reversal, approximately 65 to 70 percent of the time, Boroden said. Nevertheless, the time cycles can cause a move to accelerate. Meaning, the Dow could pick up speed rather than reverse. But Boroden says the probability suggests the rally will take a breather.
Boroden also saw resistance to the rally right above the Dow's 20,000 target, with the ceiling hitting 20,193 to 20,098. So, even if the index does hit 20k, the charts suggest there is a chance stocks could run out of steam. She saw the same for the S&P, with a ceiling of 2,223.
While Boroden was not trying to call a top in the Dow and says she is not predicting a crash, she does think it is time to get more cautious and take some profits.
"I say nobody ever got hurt taking a profit, especially going into what could be a pretty tumultuous earnings season," Cramer said.