First, you should trust your practitioner. In the US at least the training is significant and the licensure strict to practice acupuncture. While there are certainly some practitioners with more experience and/or more comprehensive training than others the general safety with seeing a fully trained and licensed practitioner is comprehensive.
Now if you are seeing a DC, MD or PT who is practicing some version of acupuncture you might want to question their training.
In this instance, however, your fears are entirely unwarranted - you are not pregnant and the contraindications generally have more to do with needling depth and locations (with only a few for specific functions) - so not being somewhat far along in a pregnancy there is little reason for concern. Along those lines, points along the conception vessel meridian are actually not contraindicated during pregnancy. If you read the pregnancy contraindicated points page you will find that the contraindications are related to needling depth and direction with those points not their avoidance. Furthermore, which I have expressed in more detail in multiple posts on this forum, many of the "contraindicated" points can and will be used during pregnancy by practitioners at various times for specific reasons. This is all part of the comprehensive nature of acupuncture training for licensed practitioners.
Generally there is more that Chinese Medicine can offer in the way of strengthening for avoiding miscarriage - particularly in someone with your history and nearly nothing that can be done except by someone with no training that could foster a miscarriage and even without training it would be a million to one for many of the above stated reasons.