By Bartosz Dabrowski

(Reuters) - Sonova Holding AG, the world's biggest maker of hearing aids, on Monday reported first-half core profit above analysts' expectations and maintained its full-year guidance as business picked up from a pandemic dip, but warned of supply chain constraints.

The Switzerland-based company said adjusted earnings before interest, taxes and amortisation (EBITA) hit 406 million Swiss francs ($442 million), above the 386 million francs expected on average by analysts in a company-provided poll.

During the early part of the pandemic, patients were deterred from seeing doctors or audiologists by lockdown restrictions and fear of infection, but many have started to seek treatment again as they gain confidence in protective measures taken in stores.

The company maintained full-year targets of a 24%-28% increase in sales and adjusted EBITA growth of 34-42%, despite some analysts expecting it to lift the forecasts.

Although JPMorgan said it had expected bigger sales and earnings beats, it called the decision to reiterate the 2021/22 guidance "quite conservative".

Sonova said it had faced shortages of microelectronic components towards the end of the first half.

"We have included the current supply chain issues in our full-year guidance," Chief Executive Arnd Kaldowski told Reuters in an interview, adding that if problems in the second half remained at a similar level to those in August and September, the company would be ready for them.

The disruptions to the global economy during the pandemic have upset supply chains across continents, causing shortages of goods and services, including microelectronic components used for hearing aid.

Sonova shares were down 3.2% by 0850 GMT.

The company's sales in April-September came in at 1.60 billion francs, 50% above last year and beating analysts' estimate of 1.57 billion francs.

($1 = 0.9193 Swiss francs)

(Reporting by Bartosz Dabrowski in Gdansk; Editing by Tom Hogue, Sherry Jacob-Phillips, Kirsten Donovan)