In many Ashkenazic families, it is customary to add a candle to the Shabbat candelabrum when a baby is born. When you know you are pregnant or otherwise expecting a baby, add an unlit candle to your Shabbat candles. It stays there throughout the months of waiting, a symbol of expectation. In the happy event of the baby’s arrival, it joins its fellow candles and is lit every week with the others to welcome the Sabbath. (If the expectation of this new life is prematurely disappointed, the candle is burned down, like a mini-yahrzeit candle.)