In a randomized clinical trial, 47 subjects were assigned to a placebo, a topical nonsteroidal anti-inflammatory agent, or a topical anesthetic.

The new study, with more than 2,000 participants, was a clinical trial in which women received either fish oil with DHA or a placebo (vegetable oil).

But the new study, which mainly assessed full-term babies, found no cognitive difference at 18 months whether mothers received DHA supplements or placebos.