A very long time ago, I read this fic where H.G. Wells shows up to tell Lois and Clark about a universe where their counterparts were doctors...Or scientists...doctor scientists? Anyway, they wore lab coats, and Dr. Lois was pregnant. Does anyone have the title?

Queenie,

In one of my recent fics I have Lois and Clark performing surgery to remove a brain tumor from a little girl that Superman had rescued from a high-rise fire. (Lois is super and pregnant and they perform x-ray surgery.)

Probably not the one you are looking for. That was Matchmaker Chronicles Volume 7 - Clark and Lois - Two Universes.

If you are interested it is part 4 of the Clark and Lois arc within the Matchmaker Chronicles. The order is:
MMC Vol 3 - Clark and Lois - The Lost Years
MMC Vol 4 - Clark and Lois - Despair to Hope
MMC Vol 5 - Clark and Lois - Hope Realized
MMC Vol 7 - Clark and Lois - Two Universes
and the final installment is -
MMC Vol 8 - When Worlds and Universes Collide.

The reason that Vol 6 is skipped is that it is part of another arc within the set.

MMC Vol 1 - Lois Lane - Mother of Utopia
There are several shorts in between 1 and 2.
MMC Vol 2 - Borrowed Time
MMC Vol 6 - Lori and Clark - The New, New Adventures of Superman

You can read the Clark and Lois set by itself, however there are characters introduced in other stories that join in the final volume. It is best to take the entire set in order.

Are you thinking of Medical Miracles by Alicia U? In this story Lois and Clark are helped by HG Wells and Dr. Clark Kent and Dr. Lois Lane from another universe. The doctors are both medical bioengineers, and Dr. Clark is also a physiologist. Dr. Lois is pregnant. Mr. Wells brings the two doctors with research to resolve Lois & Clark's fertility problem and also to protect Clark from kryptonite.
There's also a sequel Medical Miracles II: Serendipity

Cuidadora, that's it! Thank you!

And KenJ, thanks for the recs; I'll keep it in mind.

There is also Lifeflight I by Raconteur and the two sequels. Lifeflight II, Lifeflight III. They are both doctors at a hospital.

Yes!!! I was looking for that. These are great stories. Anything by Raconteur is wonderful. Someday I hope she will come
back to the boards.

Artemis