This week's surprise pregnancy... at 46.

Forty-six-year-old fashion designer Collette Dinnigan has announced she’s four and a half month’s pregnant. She’ll be 47 when she gives birth.

In an article that ran in The Daily Telegraph, Collette said she was thrilled to be pregnant (she conceived naturally) but noted her pregnancy should not necessarily be used as a benchmark for other women looking to get pregnant later in life.

“It’s no secret we wanted to (have a baby), we got married last year so we’re very happy it’s happened,” said Dinnigan, who married her 36-year-old partner Bradley last year and has a seven-year-old daughter with entertainment reporter Richard Wilkins.

“But it’s one of those things for women. I think you should never wait too late in life, but we consider ourselves really fortunate.

“I think people see so many Hollywood stars out there having babies in their 40s. It’s a message that I think women need to understand it’s very difficult to have a baby in your 40s.”

“You really need to start a lot earlier if you want to start a family and I think there are a lot so misconceptions that it’s easy to have a career and then start a family at forty.”

Some facts about fertility and how a woman’s age affects her chances of getting pregnant from yourfertility.org.au:

• Starting at about age 32, a woman’s chances of conceiving decrease gradually but significantly.
• From age 37, the decline in a woman’s ‘fertility potential’ speeds up.
• By age 40, fertility has fallen by half.
• More than 70 per cent of under-30s women conceive within three months. For women aged over 36, this drops to about 40 per cent.