SINGAPORE- A man who had sex with his elder stepdaughter about twice a month over a two-year period was jailed for six years on Thursday.

The girl was 14 when she had consensual sex with her stepfather in July 2011. She gave birth to a boy earlier this year.

A district court heard that she did not realise she was pregnant even when her abdomen was growing larger in August last year.

The accused, now 28, also noticed her growing abdomen and asked her about it. She told him that she did not have any symptoms of pregnancy.

He did nothing further and continued having sex with her, said Deputy Public Prosecutor James Low. By the time she saw a doctor at a polyclinic in October last year, she was 21 weeks pregnant.

The court heard that the accused, then a senior sales advisor, was a father of one and a divorcee when he married the victim's mother in early 2009. His 33-year-old wife, who is a sales representative, has three daughters, including the victim from her first marriage, and a four-year-old with the accused.

The accused pleaded guilty to nine of 45 charges.

Investigations revealed that on July 31, 2011, he was watching pornography online at home when the victim saw this and asked what he was doing. He asked her if she was interested to have sex with him and she agreed.

They had sex on eight other occasions from September 2011 to February last year.

The court heard that the accused continues to live in the Housing Board flat with the victim and her family.

Among the aggravating factors cited by Mr Low were an abuse of trust; the offences happened in the sanctity of the home when other family members were either out or sleeping; the sex was unprotected, and the offences happened over a long period of time.

Defence counsel Mohan Das Naidu said his client is now unemployed and does odd jobs by helping his aged father. He said the victim did not complain to anyone and his client had shown remorse by pleading guilty.

The accused could have been jailed for up to 10 years and/or fined on each charge.