I am overjoyed to be pregnant for a third time. Now at nine weeks, I’m looking back and reflecting on the journey here.

At the age of 30, it hasn’t been as easy to get knocked up this time.

My first two babies, Callum and Sean (now five and three years old), arrived with no problems. All I had to do was let nature take its course.

Now, I’ve always wanted to have three kids, and being a mother of two boys has been so rewarding that I found myself yearning for a third child.

Thus, it came as a rude shock to learn that it would not be as "automatic" to conceive again. The reason is this: In 2004, my husband was diagnosed with cancer.

Although he has recovered, there have been lasting side effects from three major operations and chemotherapy treatments. In particular, his sperm count has dropped. Conceiving naturally was thus unlikely for us.

A long series of conversations led us to the conclusion that we should be happy with two healthy boys. Besides, I had also been thinking about returning to full-time work.

But, as time passed, I found that my urge to have another baby was not reduced by this perfectly logical plan to stop at two. Several of my friends got pregnant or gave birth to gorgeous newborns, just as I was battling these feelings. I felt an irrational sense of envy as I held their new babies.

I had to constantly remind myself that I’ve already got two wonderful kids. But I realised that I wanted to try to conceive again. I discussed this with my husband, and he agreed to make an attempt.

Luckily, my husband – before his cancer treatments began – had had the foresight to have some of his sperm frozen and kept in a sperm bank in a reproduction clinic. He had been aware of the possible side effects of his treatments. Thus began the expensive, heartrending process of assisted fertility.

We had meetings at three separate clinics to get a range of views about the reality of our situation. After many consultations, we settled on giving intrauterine insemination (or IUI, where sperm is injected directly into the woman’s uterus) a go.

Six months of blood tests, examinations, procedures, waiting and disappointment passed. Suddenly, everything revolved around one question each month: “Will I get pregnant this time?”

Several couples I know have gone through many difficult cycles of assisted fertility, only to face disappointment time and again as they never conceived. It’s the disappointment that kills. I should know: Even with two healthy kids in my wonderful family, the inability to have one more became a daily burden on my heart.

Irrationally, I felt that I was failing to provide my family with another son or daughter, a brother or sister, a cousin or grandchild. For those with no children at all, it must be an immense emotional challenge. My heart goes out to them.

We were fortunate. After three attempts at IUI, I conceived. I have never been so happy or excited to get morning sickness.

Assuming all goes well with this pregnancy, I will have my desired three children. Will irrational urges take over and lead me to want baby No. 4? Maybe. But for now, I’m just looking forward to showing off my baby bump and unpacking old baby clothes I’d put away.

And, of course, I’m happily wondering every day if this baby will be a boy or girl.

Karen Cheng is a mother of two who lives in Perth, Australia. She is the author of a popular lifestyle and fashion blog – www.karencheng.com.au.

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