From the article:
Study participants were randomly assigned to one of three treatment groups for six months: (1) oral estradiol and progesterone at a dose similar to that in many birth control pills (16 participants); (2) transdermal estradiol, better known as the estrogen patch, at a physiological replacement dose with cyclic progesterone (13 athletes); or (3) no estrogen (19 subjects). Participants who received estrogen therapy also received progesterone because giving estrogen alone can increase the long-term risk of uterine cancer, Baskaran noted.
[…]
Compared with those who received no hormone treatment, athletes in the two estrogen treatment groups taken together had significantly better verbal memory and cognitive flexibility scores at the end of six months than their pre-treatment scores, the investigators reported. The estrogen recipients had greater improvement in both immediate recall of words and in their ability to flexibly switch back and forth between tasks, even when the researchers controlled for patient age and pre-treatment test scores.
When the researchers evaluated the estrogen treated groups separately versus no treatment, they found significantly greater improvement in certain cognitive tests only in the group that received transdermal estrogen.