The issues in this case were no different than any others presented before and so he knew that any anti-Roe decision on his part would ultimately be overturned.
In a sense he did the pro-life movement a favor by not creating yet another Supreme Court ruling in favor of Roe and adding to the Supreme Court's stare-decisis support of Roe.
From the case under discussion. I'll let Judge Luttig give his explanation. Key paragraph. LINK
As a court of law, ours is neither to devise ways in which to circumvent the opinions of the Supreme Court nor to indulge delay in the full implementation of the Court's opinions. Rather, our responsibility is to follow faithfully its opinions, because that court is, by constitutional design, vested with the ultimate authority to interpret the Constitution.
I think we're in agreement on the case in point and on Judge Luttig making a fine member of the SCOTUS.