At 7:30 a.m., a well-known infertility clinic in East Taipei is thronged with women who have rushed to register for a doctor's visit before their work days begin. Some have come for injections of fertility drugs to induce ovulation. Others are busy giving blood samples. And still others, eager to advance a step further in their fertility treatments, are undergoing ultrasound imaging to observe their ovarian follicles' speed of growth.

These women share some things in common: They typically are well-dressed in up-to-date fashions. Many are mid-level executives. Yet no matter how exquisitely made up, they can't hide the tracks of time on their faces. Most are at least closing in on 35, and quite a few have even passed 40. One and all, they are willing to suffer pain and bodily indignities, as well as spend great sums of money, to accomplish one goal: realize their dream of becoming mothers as soon as possible.

Success rate of pregnancy (brown line) and live births (green line) from in-vitro fertilization in US, 2005 / source: Dr. Liu Chi-hong, infertility specialist

Racing their biological clocks

This group of mature women must rely on outside help to reach their goal of holding a bundle of joy because their ovaries, fallopian tubes or uteruses have undergone pathological changes, so that they can no longer naturally become pregnant like other women.

But that gets it only half right: The main reason that they can't easily become pregnant is that they are no match for the inexorable turning of their biological clocks. Even if they are still in good shape and look young on the outside, on the inside their bodies-much to their frustration-have started to change according to a timetable set by millions of years of human evolution. They are no longer like women in their 20s who can bring forth healthy eggs at any time to create a new life.

"Among women, there is a clear 'negative correlation' between age and fertility," says Hwang Jiann-loung, the president of the Taiwan Society for Reproductive Medicine, and an obstetrician at Shin Kong Wu Ho-Su Memorial Hospital. Unlike men, whose testicles can produce a virtually "unlimited" number of sperm even at 50 or 60, and who demonstrate a reproductive vigor "like dragons," a woman's fertility is more like a "warehouse," with a limited capacity and with stores that are slowly exhausted over time.

When a baby girl is in her mother's womb, her ovaries are implanted with nearly 7 million eggs. By the time she is born, about 2 million remain. Then, over the course of childhood the number is reduced, so that when she hits puberty perhaps only 250,000-300,000 remain. More are lost every time she has a period.

Hwang emphasizes that as a woman gets older, apart from losing eggs and having aging ovaries, her reproductive organs are more likely to have undergone pathological changes. For instance, older women are more likely to suffer from fibroid tumors of the uterus, endometriosis, and obstructed fallopian tubes. All of these conditions can negatively affect their chances of becoming successfully impregnated. Consequently, women have the highest chances of becoming pregnant at ages 25-30. Once they get into their 30s, their rate of success starts to gradually decline. And once they are over 35, their chances of success decline 15% per year.

Liu Chi-hong, one of Taiwan's best known infertility experts, says the area of his clinic that receives the most attention is this wall pasted with photos of newborns. Smiling, he says that he and modern reproductive technology helped to "manufacture" these babies.

Missing your chance

Despite the startling impact that the physiological clock has on one's ability to give birth, many women lack understanding about these issues and don't give much thought to the urgency of the situation when they are in their most fertile years. Perhaps because they are busy establishing themselves in their careers, or they haven't had an opportunity to meet an ideal mate, or because their economic situation isn't fantastic, or because husband and wife want to enjoy more years as DINKs (double income, no kids), these women put off giving birth when they are young. They wait, gradually getting older until they discover that their lives have everything except a little bundle of joy that is their own flesh and blood. Then they become shocked to learn that they have missed the ideal time to give birth, and that the costs will now be higher to realize their dreams.

Ms. Dai, who turned 41 this year, is a case in point. She works in a technology field, and because she was always so busy with work, was picky about prospective mates, and had a narrow circle of acquaintances, she was unable to find Mr. Right for many years. Finally, through an introduction of friends, she met her husband, who is four years her senior, when she was 38.

In the first year of marriage, the husband and wife, each used to spending their time off work in leisure activities, weren't certain they wanted children and continued to use birth control. But Dai had a change of heart after attending the funeral of a co-worker's father.

"It was a cold and simple ceremony, with few in attendance apart from his children and closest relatives. I suddenly thought: I'm already getting up in age. If I don't even have children to make arrangements for me, how depressing that would be!"

Dai thus began to think seriously about having a child, and she convinced her husband that they should "get to work" on it. But by then Dai was already at the "advanced age" of 39. No matter how diligently she recorded her temperature, calculated her ovulation period, and arranged the schedules of her husband and herself so that they could "do their homework," nothing came of it. After eight months of trying on their own, they sought help from an infertility clinic.

"The doctor said my uterus and fallopian tubes were normal, and that my age was the only reason I was having trouble getting pregnant," says Dai wryly. She had always thought that it would be easy to get pregnant as long as she was still having periods, and was often hearing reports of famous people or distant relatives getting pregnant after 40. "I had never realized that these people were the exception!"

On her doctor's advice, Ms. Dai had one artificial insemination procedure and two in-vitro fertilizations before becoming pregnant more than a year later. She's now four months pregnant, and when she thinks of the life growing in her belly, she can't help but say: "If I had known earlier that it would be so hard to have a child at an advanced age, I would have reconsidered my life plan."

In comparison to men, who can produce virtually unlimited numbers of sperm, women's eggs are precious commodities that are produced in only limited quantities. Consequently, it is important that women grab hold of opportunities to become pregnant during the golden years of their fertility. The photo, from an exhibtion on human reproduction at the National Museum of Natural Science, shows tadpole-like sperm swimming toward their target: an egg.

Limits of technology

There are in fact many who, like Dai, overlook the negative impact that age has on fertility.

In 2006 Hsu Kan-lin, an assistant professor of public health at National Cheng Kung University's College of Medicine, conducted a major survey of knowledge and attitudes about fertility. When asked at what time fertility begins clearly to decline, a surprising four out of 10 respondents answered that they didn't know or "after age 50" (after 35 is correct). About 30% of respondents thought that people in their 40s have a 50% or better chance of success with in-vitro fertilization, whereas there is in fact only a 15.5% success rate among those ages 41-49.

And there were higher rates of wrong answers among those with college education or higher. Hsu avers that people with high educations and socio-economic status are often "focused on their careers and enjoying life." Marrying and having children is of secondary importance to them, so naturally they don't pay much attention to fertility issues.

What's more, members of this group, who tend to put great faith in technology and believe that human power can overcome nature's challenges, often hold unrealistic confidence in the powers of modern medicine. Consequently, they are inclined to believe that "it's no big deal to put it off until later."

Interestingly, when the survey asked, "If waiting until 40 would hurt your chances of becoming pregnant, would you try to become pregnant earlier?" 75% of respondents answered affirmatively. That percentage shows that, along with work, lack of a partner, and economic pressures, ignorance is also one of the main reasons that some women put off trying to get pregnant.

Success rate of pregnancy (brown line) and live births (green line) from in-vitro fertilization in US, 2005 / source: Dr. Liu Chi-hong, infertility specialist

Bad eggs

Liu Chi-hong, a nationally famous specialist in infertility, believes that when you get to the roots of explaining why the public has such a poor knowledge about fertility issues, with an understanding that deviates so greatly from reality, the media can't escape some blame for spreading inaccurate information.

"Many women are 'tricked' by reports in mainstream media about celebrities giving birth at an advanced age," says Liu, who notes that patients often come to his clinic and get right to the point: If Betty Wu had a daughter at 44, and Bridgette Lin had a second girl at 46, and the wife of industrialist Chen Youhao had boy-girl twins at 56, "then of course I can still give birth at 40."

But is that really the way it is? Of course not! First of all, asks Liu, who knows how much money these famous individuals poured into infertility treatments? (Artificial insemination costs about NT$20,000 per attempt, and in-vitro fertilization about NT$100,000.) Could middle-income people bear the costs of failing repeatedly before finally achieving success?

There is another key point that is rarely discussed about these famous cases of older women giving birth: They quite possibly "weren't using their own eggs."

Citing statistics from the US Centers for Disease Control and Prevention, Liu points out that 42-year-old women who receive IVF treatments have only a 15.1% chance of pregnancy, but because they have low-quality eggs, they are more likely to miscarry, so that only about half of their pregnancies result in live births (bringing the success rate down to 8.4%). Two years later, at 44, the figures stand respectively at 8.3% and 2.6%. At 47, success at getting pregnant falls to 1.1% and success at giving birth drops to 0%. For most women, as these numbers make starkly clear, getting pregnant with one's own eggs after 45 is a mission impossible.

"Yet anecdotal media reports about these celebrities never mention suspicions that they may be carrying someone else's eggs," he says. "It naturally leads to misperceptions."

Estimating "fertility limits"

Liu Chi-hong emphasizes that every woman's reproductive capacity is different, but typically five years before it ends their periods will start to become irregular, and their fertility would have begun to drop markedly about four or five years before this irregularity.

"So clinically speaking, it is certainly not the case that because 'so-and-so and so-and-so gave birth when they were 40, I can too.'" Liu says. "It may well be that 50 is the end of the line for them, but it's bye-bye for you at 45." Smiling wryly, Liu says that this way of putting things may sound heartless, but it's true.

Although there is no test yet that can accurately determine a woman's "last birth year," there are a few simple benchmarks that can help a woman make her own estimate. First of all, a woman should observe her own periods, Liu suggests. If she has a 28-30-day cycle and then it suddenly becomes 25-26 days after the age of 35, that's a warning sign. "When the menstrual cycle begins to shrink that often means that your ovaries are aging and their functionality is beginning to go downhill."

A woman's mother and sisters are also important indicators. If one of them has lost fertility at an early age, there's a one-in-three chance that she'll follow in their footsteps. What's more, if she smokes, has had uterine surgery, or has a history of malignant tumors with chemotherapy or radiation, she should be prepared: her fertility is likely to decline faster than most.

"The general state of your health, family history, and surrounding environment can all provide clues. If you study them carefully you may well get early warning signs about the race against your biological clock."

Be that as it may, Liu urges every woman: If you want to have your own bundle of joy in order to complete your life, then by all means don't dillydally or assume that you'll get lucky later in life. Getting to work at the right time is the best way to prevent future regrets!