Looking good when you’re gaining 10 pounds a month during mid- to late-pregnancy is a challenge that feels about as surmountable as swimming the English Channel.

But author and style expert Amy Tara Koch is making ‘pregnancy style’ a bit less of an oxymoron these days with her new style book, Bump It Up.

The author and mother of two young girls debuted her illustrated tome yesterday at a pro-pregnancy event at the W Hotel in Westwood. There, dozens of ladies sporting baby bumps milled around vendor tables occupied by big baby brands including Britex and Baby Bjorn.

The book gives sage fashion advice and features cool indie-style illustrations of ensembles — instead of photos, which Koch worried would date the book a little more quickly. It also includes original sketches of cutie maternity looks by DKNY, Milly, Rachel Roy and Isaac Mizrahi, among others.

“I wanted to show that women don’t have to spend a lot of money when they’re pregnant to look good,” said Koch, jangling a wrist full of gold bangles. “It’s all about accessorizing. I am SO into accessories.”

Illustration from “Bump It Up,” courtesy of Ballantine Books.