I read a small amount of material about Princess Adelaide of Loewenstein's mother in Letters of Feodora, Princess of Hohenlohe-Langenburg from 1828 to 1827:
Agnes Princess of Loewenstein nee Hohenlohe-Langenburg, died of a fever more than a week after childbirth with "complete presence of mind." Feodora described her as "very handsome" and amiable. Constantin Prince of Loewenstein spoke to Feodora about his sadness about the loss of his wife.