What is the most plausible biological mechanism by which poking a little need in the neck could lead to increased conception?
Even though it doesn’t exist, traditional Chinese “medicine” also known as acupuncture goes by many terms: folk medicine, traditional medicine, alternative medicine, complementary medicine… and when people stop paying for the old one, you need to rebrand it. All that esoteric talk about yin and yang, dao, modalities, and mindfulness is fine as long as you consult a real doctor. If you went to a legitimate specialist for treatment and you’re convinced that “music therapy” helped you get pregnant, that’s fine, but don’t pretend that you should write a book about it.

This creature is not a fan of traditional Chinese medicine and wants you to stop killing him so he can drink his blood.
The same goes for acupuncture: it works so poorly that even fake acupuncture is just as effective as a “real” placebo, yet people continue to sell it to gullible people with credit cards.
The only thing that limits the effectiveness of acupuncture is your budget: if you can afford a placebo twice a week, great, but if not, once a week should suffice. still wonderful.

If you’re reading the New York Times because they’re endorsing acupuncture and all this nonsense, then I know how you’re going to vote.
0 acupuncture treatments a week for fertility problems is great for your bank balance. They sell magic to rich white women. 29% effectiveness is good enough. If you’re already a believer, you’ll be convinced acupuncture is real. This is the definition of the placebo effect, a hurdle acupuncture has never overcome in clinical trials.
And it never will be.
