Guest blogger Jessica Katz: A few of my mommy friends have been suffering from a mysterious but painful ailment. It has made it impossible for them to pick up their babies and do simple tasks such as bathing. Then they were diagnosed with something called "mommy thumb."

Also known as De Quervain's tendonitis, mommy thumb is an inflammation of the tendons from the thumb down to the wrist. Although the condition has been around as long as parents have hoisted their children, doctors say that a combination of heavier children, older new mothers, cribs that are lower to the floor and frequent scrolling and typing on smartphones has sent the number of cases skyward.

One friend thought she had sprained her wrist and subsequently wore a brace, which made it difficult for her to take care of her son. She was in a lot of pain. Then another new mom said, "You didn't sprain your wrist. You have mommy thumb!"

Orthopedic surgeons estimate that between one quarter and one half of new mothers experience the symptoms of De Quervain's. When common pain relievers don't ease the inflammation, patients are getting steroid injections, splints and even surgery. People with De Quervain's typically experience pain on the thumb side of the wrist that radiates up the forearm. Sometimes the symptoms start during pregnancy. Doctors aren't sure why, but they believe that swelling adds pressure to already stressed tendons, exacerbating the irritation.

For many women (and some men), the pain gets worse once they are constantly lifting a child, bending down into the crib, putting their hands in an "L" shape under a child's armpits and lifting so that much of the weight is on the thumbs. Mommy thumb mainly affects two tendons: the abductor pollicis longus (or long thumb abductor) and the extensor pollicis brevis (or short thumb extensor). The tendons come into play when the thumb is moved in a different plane from the hand, as when placing hands flat on a table and lifting the thumb toward the ceiling.

If ice and anti-inflammatory drugs don't help, most patients are fitted with a splint that prevents them from moving the thumb and are also given a steroid injection, which decreases the inflammation, says Stephen Troum, a hand surgeon in Bedford, Texas, and a spokesman for the American Society for Surgery of the Hand, a doctors' association.

Moms, have you ever experienced mommy thumb? Tell us!