She eventually told officers that she had gone into labour on a flight home from a holiday to Turkey and gave birth to her son - but he was stillborn, the MailOnline reported.
The court heard today he was born full-term weighing just over 3lbs.
Prosecutor Jeremy Evans said the baby was found to have a fractured skull, although this may have been caused by a shovel used to extract his body.
No cause of death could be found due to the decomposition of the body and the judge said it will never be known if the baby could have been saved by medics.
Connett carried on as normal until the mummified remains were found nearly three years later by a plumber investigating a drain blockage.
The university graduate, who was working in Tesco's HR department, denied all knowledge but DNA evidence revealed her to be the mother.
Connett, of Hertford, then invented a "lattice-work of lies", claiming to have become pregnant after being raped by a cabbie while drunk after an office party.
The truth was uncovered by police despite a "lattice-work of lies" from Connett, who cried as she was jailed for 12 months after admitting concealment of a birth.
Ignoring pleas for mercy, Judge Jeremy Richardson QC told her: "You are the architect of this deplorable situation and you must be punished."
Her parents Stuart and Anne Connett, of Grimsby, and her boyfriend Jonathan Layfield, whom she has since married, had no idea she was pregnant or had given birth. Connett had given 'health' reasons for having a bloated stomach.
Grimsby Crown Court heard she had her pregnancy confirmed by a GP in January 2013 but delayed going to an abortion clinic until May.
She lied about her dates and said it was "not the right time to have a baby". Staff refused to carry out a termination as Connett was 28 weeks' pregnant.
Nigel Sloane, defending, said she had lost her job and good character. The court heard that the baby has now been given a dignified burial.
Judge Jeremy Richardson said: "You deceived everyone in a latticed web of lies. You are the architect of this tragedy.
"As a consequence of your truly deplorable conduct you have brought misery and shame on you and your family."
The judge added: "There is no escaping the fact that your dead son lay buried in a drain at your parents' home for three years. You put him in that drain.
"You deprived your dead son of any dignity. Many would describe your conduct as wicked.
"You wanted to conceal the pregnancy, the birth and the death of your son. Your conduct was truly deplorable."
Connett managed to hide her pregnancy, the birth and the death of her son from her whole family, including her now husband, who she married in November last year.
The baby's body is thought to have been placed in the drain at the property in Grimsby, Lincolnshire, on August 9, 2013, but wasn't found until almost three years later on February 11, 2016.
When initially questioned by police, Connett denied the baby was hers.
Her lie was backed up by her unwitting mother who told police officers her daughter was 'career minded' and didn't want any children at this stage in her life.
Her deception was unmasked when blood stains on the towel matched with a voluntary DNA sample she gave to the police.
She also told police she was unaware of the pregnancy until it was too late to terminate it; however, police found medical records showing she had visited her GP in January 2013 who recorded she was pregnant.
Connett's GP referred her to an abortion clinic but she delayed going until May 2013 when she was 28 weeks pregnant - beyond the legal limit for a termination.
The 29-year-old even went on holiday to Turkey while heavily pregnant and the court heard it was likely she was in labour during her flight home from Turkey on August 6, 2013.
Connett, recently of Hertford, eventually told officers in her final interview she gave birth to a stillborn baby boy on August 9, 2013 in the bathroom of her flat in Margate, Kent, without any medical assistance.
After the birth, Connett cleaned up after herself and hid the body in the boot of her car.
On August 9, she dumped the baby's body in the drainage pit at the back of her parent's modest-sized property in Grimsby, Lincolnshire.
Connett's father Stuart phoned for a plumber three years later after the couple began having problems with their downstairs toilet and the body was found.
Connett, who has worked in HR for retailers Marks and Spencer and Selfridges, appeared wearing a black suit and carrying an overnight bag and broke into tears as she was led away from the dock.
Her family waved goodbye and her husband Jonathon blew her a kiss.