Yes, when an hCG injection’s timing cannot be shifted to just before or after Shabbat, then it is permissible on Shabbat. The needle should be assembled prior to Shabbat (taking precautions to keep it sterile—and checking whether it then needs refrigeration). You can use an alcohol wipe to disinfect the skin just prior to injection. If you don’t use wipes on Shabbat, alcohol can be poured on the injection site directly.
These halachot apply to Yom Tov as well.
Please write back with any further questions.
You may also find it helpful to consult a Yoetzet Halacha Fertility Counselor, a Yoetzet Halacha who has completed additional specialized training in this area. Consultations are free and can take place in person, by phone, or via internet conference.
This response was updated on 24 June, 2021.