A lot has been written about primary infertility, a medical condition which affects one in six couples of childbearing age in Australia and one in five in New Zealand. But there is another more silent group which doesn't get to voice their anguish as publicly. They are the couples going through secondary infertility.
They commonly have one child, in some cases conceived naturally or through IVF, but then the second one does not come along as planned.
Secondary infertility comes with its own specific hardships. While couples who have managed to have a child are extremely grateful to have one, they still go through a tormented journey and are not always given the sympathetic ear they need.
Yvonne Mattson a secondary infertility sufferer and member of Access Australia, the charity which represents Australia's infertile couples, says: "Infertility is usually referred to when discussing childless couples. Secondary infertility is a very real problem but much less obvious. People often think if you have one child, then surely that is enough. But they’re wrong. When your freedom of choice is taken away, it puts a different perspective on things. Not being able to choose or control whether you can have more children means losing that freedom of choice."
Adds Dr Anne Clark, medical director of Access: "It is also important to remember that you have the right to the family size of your choice. You are not being selfish and your efforts to get pregnant again will not deprive other couples who want to have a child."
People often think if you have one child, then surely that is enough. But they’re wrong. When your freedom of choice is taken away, it puts a different perspective on things.
"If you had no difficulty conceiving or carrying a pregnancy before, the initial reaction to realising you have a fertility problem can be confusion and disbelief."
From a practical point of view, the finances are very different for the couples going through secondary infertility. Often the woman may be home with their child, so the man is the sole breadwinner and paying for all the household expenses and the medical costs on top.
"When couples are faced with infertility the first time round, both partners are usually in full time paid employment, and with two incomes this eases the enormous financial situation, if ever so slightly. With secondary infertility you are usually down to a single income and a toddler to add to your cost of living, not to mention the doctors' bills, clothing and kindy fees," says Mattson.
While women going through infertility treatment will often avoid the company of children and pregnant women because it is so painful, mothers of only children spend a lot of time with playgroups and other families because they want their children to have company.
And the number one topic of mothers' groups of course is: "When are you going to have your next?"
As Jane, the mother of six year old Olivia puts it, people are less careful about what they say in front of mothers experiencing secondary fertility than women who have never conceived.
"People assume that your one child status is a choice – that you're focusing on your career," she says.
Jane became resigned that she would have no more children a year ago after a last devastating miscarriage. After the birth of Olivia, who was conceived through IVF, she kept on trying for another three or four years until she was 39.
Since that time, she has been going through a grieving process. "It was the death of an opportunity for me," she says. "It becomes part of your history, part of who you are."
With a beautiful daughter whom she adores, she says, "I am so much luckier than some people." She understands this, but because she has Olivia, she feels that she is denied permission to grieve for the other children she didn't have. "It's as if I am not entitled," says the lawyer.
A common complaint from those going through secondary infertility is the support is not always there. Maria, 42, the mother of two year old, Heath, is currently on anti-depressants at the end of her attempts to have a second child.
"I was losing it in front of Heath and that was awful."
After her success with Heath, she assumed that she would get pregnant again but her age counted against her. Maria's first marriage broke up in her mid 30s setting back her plans for a family.
"As it turned out Heath was a bit of a miracle, he was an aberration."
Her husband, who is 50 next year, has been supportive throughout but with a grown up daughter and Heath, he was able to call it quits before her. They've spent $50,000 on IVF.
"He probably doesn't understand my depths of despair," says Maria.
"In some ways having a child, you realise how amazing it is and not being able to repeat it is right up there with not having one at all."
The businesswoman says she has not found the support that she needed.
"People assume that you will deal with it a lot better than couples who can't have children. People assume you have got one, you'll be fine."
Coming from a close family, Maria wanted a sibling for Heath. “I have a wonderful relationship with my sister. To not have that – it's a different sort of life. I feel for my son."
"We compensate. We have constant playdates."
Read author Gill South's additional article on Secondary Infertility here.