According to an article in the January 3, 2012 Wall Street Journal, the answer is yes.

Fertility rates have been found to improve in women getting a placebo, perhaps because they experience a decrease in stress. A recent randomized trial of women with polycystic ovarian syndrome found that 15%, or 5 of 33, got pregnant while taking placebo over a six-month period, compared with 22%, or 7 of 32, who got the drug—a statistically insignificant difference. Other studies have demonstrated pregnancy rates as high as 40% in placebo groups.

This is consistent with and may partially explain previous findings of a benefit from Mind-Body programs and acupuncture in patients going through IVF.