Bismillah.

I came across to very interesting narration in shia book “Qurub al-Isnad”, authored by `Abdullah ibn Ja`far al-Humeiri al-Qummi:

298- الحسن بن ظريف، عن الحسين بن علوان، عن جعفر، عن أبيه:أنه كانت له أم ولد، فأصابها عطاش في شهر رمضان، وهي حامل،فسئل ابن عمر عن ذلك فقال: مروها فلتفطر، وتصدق مكان كل يوم بمد من طعام

Translation:

 al-Hassan ibn Tharif from al-Hussein ibn `Alwan from Ja`far al-Sadiq (as) from his father (as): That he had Umm Walad, and she was struck by thirst during Ramadan while pregnant, so ibn `Umar was asked about this and he said: “Order her to break her fast, and to give Sadaqah for each day missed and to feed the poor.”

Thanks to brother Hani for translation.