HILO >> More than 50 people lined a Hilo avenue Saturday to show support for an obstetrician whom the government says performed unnecessary tests on pregnant women.

Dr. Frederick Nitta tells the Hawaii Tribune-Herald he insists on testing pregnant women for up to 14 different substances to prevent them from giving birth to babies affected by drug and alcohol abuse.

He says he billed Medicaid for drug kits using a specific billing code for about three years.

The federal health care program stopped reimbursing Nitta in September. The insurer says Nitta must repay $1.2 million.

Nitta says the development may force him to shut down his practice of more than 20 years.

Nitta says more attention should be paid to young mothers abusing controlled substances while they are pregnant.