The pregnant British teenager Bella Culley has reportedly been told she will be released from the Georgian prison where she is being held on drug-smuggling charges if she pays a substantial fine.

Culley, from Billingham, on Teesside, has been detained in the former Soviet country for more than three months after being accused of trying to bring in 14kg of cannabis in a travel bag. She has been told she faces up to 20 years in prison if convicted.

Fears were first expressed for her safety when she went missing during a holiday in Thailand in May. She surfaced nearly 4,000 miles away in the Georgian capital, Tblisi, where she was arrested.

She marked her 19th birthday in prison the following month, and during a court appearance in July it emerged she is expecting a baby boy. Her lawyer, Malkhaz Salakaia, had tried to secure her release pending a trial, telling Tbilisi city court: “I want her to feel this motherhood in freedom.” However, the judge decided no new evidence had been presented and ordered that Culley remain in prison.

On Tuesday, the BBC reported Culley was back in court, where the judge, Giorgi Gelashvili, was told defence and prosecution teams had been negotiating the terms of a plea agreement that would result in Culley being freed in return for a sum of money with “many zeros”.

It was reported the lawyers were referring to Georgian lari – £1 is worth ₾3.60.

The prosecutor argued Culley posed a flight risk and could reoffend if allowed bail, the BBC reported. Gelashvili ruled that she must remain in custody until the next hearing, on 9 October, unless an agreement was reached sooner.

The Foreign Office has previously said it is “supporting the family of a British woman who is detained in Georgia”. Cleveland police, on Teesside, have confirmed an 18-year-old woman from Billingham was arrested in Georgia on suspicion of drug offences in May.