Timothy and Marie have an eight-year-old daughter. They have been trying to have another child for the past six years.
Five years ago, Marie had a miscarriage, after which the couple underwent in vitro fertilisation (IVF) in 2016. She got pregnant, but suffered another miscarriage.
Doctors could not determine the exact causes for the miscarriages and fertility screening tests have shown that Timothy, 45, a marketing manager, and Marie, 42, a housewife, are healthy. Their names have been changed.The couple know that fertility declines with age, particularly for women. Timothy describes their struggle to conceive a second child as "demoralising".
But they are currently trying for a second child through IVF again. "Even though the treatment is painful, with daily injections, there is a ray of hope, so it's worth the effort," says Marie.
Secondary infertility is defined by the World Health Organisation (WHO) as the inability to conceive or carry a pregnancy to a live birth, following a previous pregnancy. It includes those who have repeated spontaneous miscarriages or whose pregnancy results in a still birth, according to the WHO website.
Secondary infertility is the hidden factor in the societal debate surrounding Singapore's dismal birth rates, say doctors and experts.
Mrs Joni Ong, president of I Love Children, a non-profit organisation that raises awareness of fertility-related issues, says: "We've been focusing on those who can't even have their first child. We're concerned that more people are stopping at one child, some by choice. We should look more at secondary infertility."
Dr Ann Tan, medical director of Virtus Fertility Centre Singapore, says: "In Singapore, as we see couples postpone childbearing to their late reproductive years, the issue of primary and secondary infertility is becoming prevalent."
Primary infertility refers to non-parents who have not become pregnant after at least a year of having unprotected sex.
Singapore's total fertility rate fell to a low of 1.14 last year, well below the replacement rate of 2.1.
One reason for this is that couples are marrying later, which has an impact on fertility. In 2017, the median age for marriage was 30 years old for men and 28.4 for women, compared with 29.7 for men and 27 for women in 2006.
Infertility remains a taboo subject for many, which may explain why secondary infertility, in particular, is seldom mentioned in the societal discussion surrounding declining birth rates, observers say.
In addition, couples may be reluctant to talk about their failed attempts to have another child.
Timothy says: "There are people who say, why do you bother when you already have one child?"
He adds that people may pry and gossip about their failure in getting pregnant.
But he says: "We believe a family should have two kids, so that the children have company. They can share good and bad times and are not lonely.
"Our biological clocks are ticking. If we get another child, we'd be extremely happy. If not, we won't regret that we didn't give it our best shot."
Doctors interviewed by The Sunday Times say they are seeing fewer patients with secondary infertility, compared with primary infertility, in part because seeking help for the former can be complicated.
Dr Janice Tung, consultant obstetrician and gynaecologist at Thomson Fertility Centre, says: "Few couples step forward (for assisted reproductive technology, or ART) because many of them would have channelled a lot of resources to their child and may feel guilty about spending money on trying to conceive another child.
"Those who have conceived their first child easily may also take longer to realise that they have issues conceiving a second one."
This was the case for Ms Rosemary Richard Sam, 30, a senior events executive at I Love Children.
Her first pregnancy was straightforward, but she had two miscarriages last year before conceiving her second child.
She and her husband, a 34-year-old businessman, have two daughters - Ariel Damilola Tijani, five, and Iris Funmilayo Tijani, who is two months old.
"You don't expect it to happen to you, but infertility is probably more common than you think. Talking about it gives people the courage to speak up," says Ms Richard Sam.
"It took me a while to talk about it. I was crying my heart out and I just wanted to be alone."
Hearing from a blogger who had miscarried helped her get over the trauma of her own experiences. This led to her sharing her account of secondary infertility with others, including a close friend who then revealed she also had a miscarriage.
The causes of secondary and primary infertility can be similar.
Dr Tan from Virtus Fertility Centre Singapore says the situation is "aggravated by the increase in age of both partners and, with this, the possible deterioration in the quality of the eggs and sperm".
Associate Professor Yong Tze Tein, head and senior consultant at Singapore General Hospital's department of obstetrics and gynaecology, says: "The reality is that women who are older are more likely to get endometriosis, cysts or fibroids, which can be complicating factors in conceiving."
Dr Tung from Thomson Fertility Centre says there are "a lot more unexplained cases" of secondary infertility, compared with primary infertility, where medical investigations do not unearth why the couple are experiencing secondary infertility.
It is more important to focus on solutions, says civil servant Weng Wanyi, 35. Her husband, 36, works in the education industry and their first child, a daughter, is four years old.
In 2017, the year they were trying for a second child, she underwent surgery to remove an ovarian cyst.
Her doctor told her the cyst might have affected her chances of conceiving, though checks showed normal fertility levels for the couple. She underwent three failed IUI attempts between last September and May. Intrauterine insemination or IUI involves placing sperm inside a woman's uterus to facilitate fertilisation.
"We were still not conceiving and had not nailed down the problem yet. But you have to try and find the solution," says Ms Weng.
After going for IVF in July this year, she is now 3½ months' pregnant.
Family planning can go awry, she has realised.
"When we got married, we thought we would have three kids. You don't realise that having three children may take nine years. It may not work out that way either," she says.
"We've been married for 11 years and the plan was to enjoy couplehood for a while. In hindsight, I wish I had started earlier."
Associate Professor Yong Tze Tein, head and senior consultant, department of obstetrics and gynaecology, Singapore General Hospital, gives some tips on dealing with secondary infertility.
People tend to delay seeking assistance, which does not help. You do not have to keep silent. See a doctor to check if anything can be corrected with medication or surgery.
Some couples may have less sex after their first child. Try to have unprotected intercourse two or three times a week if you are trying to conceive. Once a month is not enough. Consult a doctor if you have not conceived after a year or, if you are 35 and older, after six months.
Getting to, or maintaining a normal weight, helps. Keep a healthy lifestyle, including regular exercise and not smoking.
Subscribe to our mailing list to get the updates to your email inbox...