Does the Hadith: "Indeed, Allah has relieved the pregnant and the nursing women from fasting" mean that fasting is absolutely not obligatory for them, regardless of the presence of hardship?

Allah has exempted pregnant and breastfeeding women from fasting. Scholars have qualified this general exemption with the condition of hardship; otherwise, they are not permitted to break their fast. This qualification has been transmitted from the Salaf, such as Ibn Abbas, Ibn Umar, Al-Hasan (definition), and Al-Nakha'i, and it has been agreed upon by the four Imams and others. If they fear for themselves or their children, then it is permissible for them to break their fast.