I am in the early stages of pregnancy, do I need to fast on Shiva Asar B’Tammuz? Considering its Nidcha this year.
The exemption from fasting applies only to a woman who is already in the fourth month of pregnancy, or in the case of pain from 40 days onwards. However, if suffering from morning sickness, headache and/or general weakness one is exempt already from the beginning of the pregnancy.
ראה מור וקציעה תקנ. מל״ח ט, יד. משנ״ב תקנ, ג. הנסמן בשו״ת יחו״ד א, לה.