Tsubame wa Modottekonai

Riki, a 29 year-old temporary employee who works at a hospital is struggling due to financial instability. She hears of a high paying side gig through a work colleague, and heads to the Japanese branch of Plante, a specialized reproductive technology clinic. Former ballet dancer Kusaoke and his wife are looking for a surrogate mother who will give birth to two children in exchange for a large fee.

(Source: Drama-Otaku)
~~ Adapted from the novel "Tsubame wa Modotte Konai" (燕は戻ってこない) by Kirino Natsuo (桐野 夏生).