A planet that is retrograde means that the planet was making an apparent backward motion at the time of birth. If a planet was retrograde at the time of birth, then that planet is notated in the natal horoscope with an Rx by the astrologer. Planets never move backwards, hence the term apparent. The Sun and Moon never retrograde. Many people watch the motion of current retrograde planets, especially Mercury.
From an earth view, a planet only appears to move backwards for a given length of time. Refer to the section on Planet Motion for approximate retrograde periods. In the Ephemeris, the day that a planet begins this apparent motion is designated by an R or an Rx In order to determine the length of time, run your finger down the planet information column until you find a D. On this day the planet resumes it's "direct" motion again. Some astrologers put more emphasis on retrograde planets in the birth chart than others.
The energy of a retrograde planet is expressed more on an inner level Sometimes the individual has difficulty expressing the energy outwardly. Some part of that planets energy is held back. Retrograde planets often cause one to stop and reconsider the consequences, so that spontaneous expression is blocked in some way. At other times, the outward behavior becomes exaggerated in an attempt to reconcile the inner doubts. Here are some examples of how retrograde planets may manifest in a persons chart.
Viewed in karmic terms, retrograde planets in your natal chart can indicate internal struggle regarding an unachieved goal or an unfinished life lesson or lessons. Generally, natal planets in retrograde tend to internalize their influences, allowing you to work on your character. Your Sun and your Moon are never retrograde. The closest the Moon comes is when it is Void of Course. This is a time when it is best to refrain from beginning anything that you wish to see come to completion.