Bristol Palin says she's pregnant for a second time.

The daughter of 2008 Republican vice presidential nominee Sarah Palin announced the pregnancy on her blog Thursday. Her representative, David Martin, and Palin family lawyer John Tiemessen confirmed the blog post.

The 24-year-old wrote that she knows this is a "huge disappointment" for her family, close friends and fans. She's asking people to respect her privacy, and that of her son Tripp, saying, "I do not want any lectures, and I do not want any sympathy."

Bristol Palin was an 18-year-old unwed mother when she launched an abstinence campaign soon after giving birth to Tripp in December 2008.

She was engaged to Medal of Honor recipient Dakota Meyer, but the wedding was called off days before the ceremony last month.