Red Cheeks
One of Charlotte's most salient features is bright red, blushing cheeks that are a little bit "too" red, almost as though Charlotte "painted" or wore makeup (which was not socially acceptable for young, unmarried women of that era). Tina likewise has red, blushing cheeks.
Blushing is often a sign of embarrassment or shame, and Charlotte's having given birth to a child outside wedlock was certainly deemed shameful in upper-class New York during the mid-1800s when the novel was set. Likewise, being a foundling and possibly being born out of wedlock is a source of potential embarrassment to Tina.
In another turn of meaning, bright red spots on the cheeks are consistent with some forms of tuberculosis.
Lung Fever
Charlotte's family has a history of what Wharton describes as "lung fever", which may also be known as consumption or tuberculosis. Her father died of it at a young age, and during the initial exposition at the start of the book Charlotte is described as having gone away for a year or so to recover from the same disease. She still "coughs up blood" when under stress, and in fact has such an episode prior to her wedding. It is the excuse Delia needs to convince Charlotte and Joe to cancel the wedding while protecting Charlotte's secret.
The Old Maid
By never marrying, Charlotte becomes an "old maid": socially superfluous and regarded by many with a combination of pity, contempt, and resentment. She is frustrated that her daughter sees her as an irritating kind of maiden aunt and treats her with contempt instead of with respect. Some of the activities she undertakes during the book are consistent with a confirmed spinster of her era: tutoring neighborhood children and living in someone else's home as a kind of permanent house-guest are two examples.
Clocks
On Delia's mantel is a clock from Paris bought as a wedding-gift by a relative in Germany and sent by way of Clement Spender, a former suitor of Delia's who rejected him due to his lack of means to support a family. Clement Spender is also the father of Charlotte's baby, and was devastated when the woman he loved married somebody else. Clocks appear periodically throughout the story, chiefly when there is an awkward silence broken by the ticking sound. They symbolize objective reality because they mark the passing of time.
