Great question. There are two scenarios as you pointed out:
GB21, ST12, LI4, SP6, UB60, UB67 are contra-indicated the minute someone becomes pregnant, and are NOT TO BE USED until the patient’s baby is deemed full-term (usually around 37 weeks). This is due to these acupoints having an effect on oxytocin release.
Lower abdomen and lower back are contra-indicated after the first trimester, but can be used DURING the first trimester. This is due to these acupoints being overtop of the baby and we are guarding against puncturing the placenta.