Lyda Liu never dreamed the silk-screen T-shirts she made as a child to give as economical Christmas gifts to her extended family would grow into a full-fledged business.

But the Waimea resident began selling her creations, and the business took off, with gross annual sales reaching $120,000.

She is among a number of local "momtrepreneurs," a term coined for mothers turned entrepreneurs who have successfully broken into niche markets while raising their children.

Liu, a physical therapist by trade, owns keiki kruisers, which produces handmade "playful Hawaiian designs" on T-shirts, onesies and rompers, mostly featuring a simple image of an animal with its Hawaiian name beneath to share a "tiny bit of Hawaii" with the world.

Liu was taught by her mother how to design and produce large amounts of themed shirts every holiday as gifts. She decided to use her skill to make kids’ designs after having her own children.

The business began at a local farmers market on Hawaii island and now produces novelty T-shirts for more than 50 stores statewide and for Target in Hawaii and Alaska, where the designs are specific to America’s last frontier.

"Physical therapy’s a wonderful career but this is a dream job; being able to be my own boss and flex time with my kids’ schedule is more than any parent or career person could ask for," said Liu, who started the business nearly a decade ago when her first child, 9-year-old son Kama, was born. "My two children have been a great inspiration to my business. They’ll tell me, ‘Can you make a shark or a hee (octopus)?’ They give me ideas, then it’s fun to see them wear them. They feel they’re part of the business, too, so it builds pride in themselves."

Other momtrepreneurs have launched new businesses to fill a need that was missing in the marketplace.

Carie Anderson, a 40-year-old Kaneohe mother of three who also works part time as a lab technologist specializing in tissue typing for organ transplants, started Malama Baby when she couldn’t find a burp cloth that was designed to stay on her arm while holding her baby.

After investing more than $40,000, she developed and patented the Snuzi, a padded sleeve that easily slips onto one’s arm to alleviate the heat and perspiration from a baby’s head that can occur after long periods of cradling. It took a year before she came up with a design that she was happy with, calling the first few "pretty hideous."

"That’s the whole reason the business was started, because of that one product. I just had a problem and wanted to make something that maybe other moms had the same problem with," she said. "I kind of knew it was a niche market thing; not every baby has a sweaty head. I kind of knew that wasn’t going to be the product that was going to be in crazy demand."

Anderson, who earns $25,000 in gross revenue a year, subsequently designed 10 to 15 baby products, including Hawaiian- and contemporary-print nursing aprons, a stroller caddie and a washable diaper and wipe-holder clutch with a built-in changing pad.

The business gradually started picking up, and in 2009 demand was overwhelming. So the momtrepreneur finally decided to get help with sewing and began outsourcing.

"I was just neglecting home and family. Relationships started getting strained, things started to fall apart with just home life," she said. "I’m so grateful that I snapped out of it. I’m doing this so that I can spend time with my family."

She is currently devising a combined car-seat blanket, nursing apron and stroller canopy product to add to her line of baby products.

"Sometimes I stay up all night thinking about a new product and how I can make it do what I want it to," Anderson said. "What is really rewarding is when another mom tells me they love it."

Similarly, Aiea mother Carol Kage, a full-time Realtor who founded O-baby inc. in 2009, began making breezy organic swaddling blankets out of muslin, a type of gauze material, after discovering few in the marketplace.

She hooked up with a factory in China through word of mouth, and after researching cotton — and the pesticides in the processed fabric — she began selling her products last year after the birth of her second child.

"I wanted to provide something for mothers out there, an alternative choice," she said. "I’ve always had an entrepreneurial mind, you just kind of talk about it but have never really done it. This time I was really motivated to do it because of my daughter. I wanted the best for her, the healthiest, the safest. It’s those things that motivate you."

But what began as a personal need ended up being educational activism. Kage often speaks with shop owners and other mothers about the effects of processed cotton on the environment and health. She is expanding her product selection with bibs and washcloths and will likely hire someone to run the growing business, which has seen demand increase as the popularity of organic items has grown with retailers such as Whole Foods.

Kaneohe resident Jaclyn Carreira was a stay-at-home mom of three when she started BeloBe, which sells island-themed stroller liners and strap guards, and other local baby products.

She always wanted to be a fashion designer, but when motherhood came along decided to focus on her children instead. While at home she found herself constantly looking for new ideas that were much cheaper than the products sold in designer baby boutiques.

After investing roughly $5,000 of her own money, she began designing and sewing similar products with an island flair.

"As people started to see and like it, then I wanted to do more," she said. "The good thing is that I do have the flexibility for my children. The downside is that my work is in front of me constantly. The hardest part about it is finding the balance. You have to be a pretty self-disciplined, organized person."

Her main motivating factor is seeing the success of what started out as a hobby grow into something bigger.

"Walking around the mall or at the zoo, I see people with my stuff, and I get excited," Carreira said. "I want to walk up to them and say, ‘I made that.’"