Here's a quote from your article:
"Cuba had 127,710 births in 2010, 2,326 fewer than in 2009".
If the population remained fairly constant, then the birth rate had to drop. I was speculating they were below replacement rate, but it was only a casual comment. But you woke up my curiosity, so I got on my search engine and I looked it up, and found this:
http://www.juventudrebelde.co.cu/cuba/2010-01-07/cuban-population-registered-growth-in-2009"the global rate of estimated fertility, which represents the average number of children per woman at the end of her reproductive life, was 1.63. In 2008, this indicator was 1.59."
You can read the whole article and get the figures, or do a more thorough search, but there's no doubt about it, they are clearly below replacement rate. This also means population should be stable or decreasing. A stable population would be due to increasing longevity (less children coming in but less people dying). As the longevity curve flattens out because they can't squeeze more years out of old people, then the population begins to drop.
In Cuba's case, the implications are clear: an aging population will lead to a higher ratio of non-workers to workers, which in turn means they have to have much more efficient workers. The other option they have is to import labor. Or they can start having more children.
Cuba is unique in the sense that it has a very educated population with a very high life expectancy and low birth rate while at the same time it lacks savings. This is a bad mix, a richer country could buy itself out of the jam by importing immigrants (USA) or using its savings (Japan).
But a poor country without savings can't work itself out of this without changing economic models. And this may be one reason why the Cubans are changing away from communism (even if they like to paper it over and say they are not). The model they have been trying to use isn't sustainable, and they figured this out.