I had acupuncture from someone with a specific interest in helping couples to concieve, and had my baby when I was 42. I cannot say it was causal, I think on balance it probably did make the difference.
I tried it- hated it made me really stressed and actually think it ontributed to one early mc. The only thing I found calming and think helped a little was yoga as when I felt my body was totally out of my control I learnt I could make it do things. A handstand at 35 for example. Mad but it gave me another focus and I think warmed up some of my organs if that makes sense.
I think it does as it helped me have two successful pregnancies - I didn't use it when I mc or lost baby late. That may be because helped me relax /feel less tired (it does help that) but I think it helps.
That said you need a properly trained practicioner who you trust. Not all acupuncturists are the same.