The first time I spoke to “Anna”—not her real name—she was in the process of donating her eggs. A couple wanted to have a baby, but the mother-to-be’s eggs were not viable, so they needed Anna’s. This was Anna’s fourth time donating, and she was familiar with the routine: take hormones to stimulate the development of eggs, get some ultrasounds and then have the eggs removed. She was upbeat. When I asked what she considered the best part of the experience, she listed several: The gratitude of the families. The marvel of creating life with modern technology. Feeling powerful as a woman. “We women should help each other out,” she said.

At that moment, however, there were a lot of little things annoying her. She was miffed at the nurses, who hadn’t been as attentive as usual—they even forgot to special-order her medications. (Anna lives in British Columbia, but the clinic was in Toronto; cross-province prescriptions can be tricky.) She was also negotiating about money with the agency that arranged the donation. Anna never takes a fee, but she wanted to be compensated for lost wages, and to bring a companion along in case something went wrong. She paused our telephone conversation for her nightly hormone injection. “It’s a lot of hassle,” she said, “for doing something out of the goodness of my heart.”

Two weeks later, Anna and her mother were on an overnight flight to Toronto. When she went to the clinic for her early-morning ultrasound, she got some alarming news: there were many more eggs in her ovaries than the doctors had expected. The Toronto clinic had been getting updates from a doctor in BC, who was monitoring her egg development, but there had been a miscommunication. If they’d known how many eggs there were, the clinic staff told her, they would have reduced her medication. The Toronto doctor told Anna to take her final shot, and, a day and a half later, the crop of eggs was harvested from her body.

“I remember feeling fine, completely fine,” recalled Anna, thinking back to the evening after the retrieval. She and her mother even went down to the hotel lobby for dinner. But then, Anna said, “I went into the bathroom and puked my guts out.” Things got worse after she went to bed. She started to feel short of breath. She was bloated and “puffy.” And the pain, which stretched from her rib cage to her pelvis, was unbearable. When it came time to fly home, she was so sick that she needed a wheelchair to board the plane.

Over the next two days, Anna’s abdomen swelled until she looked pregnant. She gained 20 pounds. She stopped urinating. She checked herself into the local hospital, where she ended up staying for four days, while the staff worked to manage her pain, prevent blood clots and safeguard her kidneys. “I thought I was going to die,” she said.

About five hundred egg donations take place in Canada each year, according to the Canadian Fertility and Andrology Society, a group representing fertility specialists. Exactly how many go awry is harder to say. Fertility doctors tend to claim that egg donation is very safe, and that the risk of serious complications is extremely low. It’s true that some women never have problems. “Claire,” who donated in Toronto about eight years ago, had no ill effects. On donation day, following the retrieval of the eggs, she threw a big party at her apartment, and then flew out west to spend time with her boyfriend. “Emily,” in Montreal, has donated at least eight times. Although she has occasionally experienced cramping, she usually feels well enough to take the metro home. Once, she popped a couple of Tylenol and then went shopping.

Others, though, find that the medication they take makes them weepy or nauseous, that the egg retrieval is excruciating or that they bleed a lot more than expected. Even more seriously, a few, like Anna, suffer from a condition known as ovarian hyperstimulation syndrome, or OHSS—an unfortunate side effect of stimulating the ovaries to produce extra eggs.

The CFAS told me that, between 2001 and 2010, only two donors in Canada, out of a total of 4,177 donations, suffered from “severe” OHSS, which usually involves hospitalization. Fourteen others had “moderate” OHSS. These numbers are collected in a database called the Canadian Assisted Reproductive Technologies Registry, which is maintained privately by the medical directors of in vitro fertilization clinics—a subgroup within the CFAS. Although some CARTR data, such as live birth rates, are published online, the numbers on OHSS are not routinely made public.

There are many reasons why CARTR data on donor-adverse events may not be complete. For one thing, it’s not common practice for fertility doctors to formally follow up with donors after a procedure, unless the women are specifically at risk of OHSS. Several physicians told me that they simply invite donors to get in touch if there’s a problem. Some women do so, but others may have already left town, or they’re told by brokers not to contact doctors directly. Health concerns can also turn up weeks, months or even years after the donation. By that point, it’s not clear if they’re related, so some donors don’t mention these issues to their fertility doctors. Without deliberate follow-up, doctors may not be aware of what goes wrong after the fact.

Some doctors appear to play down the problems they do know about. Immediately after Anna’s first donation, for instance, she started vomiting and felt dizzy. She was taken to hospital by ambulance for observation. When the doctor discharged her, three days later, he wrote in her notes: “It turns out that she ate a bunch of chocolates that she had in her bag immediately after the retrieval.” (She denies this.) He did not mention OHSS in those notes, or in the hospital notes from the time she was readmitted for an additional four days. Her fluid intake and output, the drugs he prescribed and the fact that he had to drain 2.5 litres of fluid from her body all point to the presence of OHSS. But the words he used in the discharge diagnosis were “abdominal discomfort.”

That case was in 2009. The physician is one of the IVF medical directors who co-owns CARTR. Did he ever tell the registry about it? I was curious, so I asked the CFAS  if it would tell me when, by year and month, the two severe and fourteen moderate cases of OHSS had taken place. The answer was no. I asked if it would tell me where these cases had occurred. It would not, citing privacy concerns for individual clinics.

CARTR collects information about hospital admissions, bleeding, infection and other immediate problems, in addition to OHSS. But reporting is voluntary, and probably incomplete, admits Mathias Gysler, medical director at Isis Regional Fertility Centre in Mississauga.

As for longer-term problems, CARTR collects no information at all, despite the fact that questions linger about whether infertility, premature menopause and cancer are more likely to occur after stimulating the ovaries. To be fair, that information would not be easy for fertility doctors to assemble, since they are specialists. Women turn to different doctors, years later, if they become ill. But the reality is that nobody in Canada is systematically tracking the health of egg donors.

Given these gaps in knowledge, I began to wonder: What do doctors tell egg donors about the risks? And what actually happens when a woman donates her eggs?

Anna, Claire and Emily are just three of the eighteen women I have interviewed over the past few years about egg donation in Canada. Some of the women donated to sisters, or to friends, and some to their own same-sex partners. Twelve of the women, like Anna, donated to strangers. Some donated only once; others, at least eight times. Collectively, their donations number fifty-two over a twelve-year span. (Most requested anonymity to protect their privacy.)

Some donated in their own cities, while others did not. Ten donations involved travelling from another province; six involved air travel from out of the country. Some women were paid. (Under the Assisted Human Reproduction Act, it is illegal to purchase human eggs, but the law is poorly enforced, and many recipients and donors ignore it.) One woman went into debt.

Among the women I interviewed, there were eight cases of OHSS that resulted in medical intervention—either hospitalization or abdominal draining at the clinic. (Two women had it once; three had it twice.) That’s a high proportion, given the CARTR numbers. Of course, these women represent just a tiny fraction of all egg donors in Canada. Small numbers like these are especially prone to bias. It could be that women who suffered injury are more likely to talk to a journalist, and so are over-represented. It could be a coincidence that I spoke to a disproportionate number of people who suffered ill effects.

But it’s also possible that problems are more common than fertility doctors report. Tellingly, two serious medical events took place after I had interviewed the women in question about earlier donations; I only found out about these donor-adverse events when I called to follow up. In other words, these women did not speak with me because they had become ill—they just happened to become ill while they were speaking with me.

It’s true that one of the women I interviewed wanted her story known so that she could spare others the same fate. But other women declined to be part of the project; one couldn’t bear to revisit her unpleasant experience.

Many of the women underscored the importance of egg donation. Some of them had gotten sick, but even as they told me about the pain, hospital visits and fear of death, they emphasized that they believed they were doing the right thing. “There were a million ways I could talk myself out of it,” one woman told me, “but they were all overruled by my kids just being so great, and thinking that I couldn’t not give that to someone else. How can we turn our backs on people who want to be parents so badly?” Indeed, some of the women who suffered adverse events—even severe ones—lamented that they could no longer help others have children. Anna, for instance, wishes that the doctors had taken better care of her; she would donate again, but worries that doing so would put her health at risk.

Egg donation involves taking eggs out of a woman’s body and giving them to someone else. Medically, it is identical to the first step of in vitro fertilization. During this step, a woman takes hormones to make extra eggs develop in her ovaries. Doctors monitor the growing eggs through ultrasounds and blood tests. They look for follicles—the fluid-filled sacs that contain the eggs—and count them. Then, when doctors find the right number of follicles of the right size, they tell the donor to take what’s called a “trigger shot.” This hormone causes the eggs to undergo their final ripening, and, about thirty-six hours later, just before the eggs would be released on their own, the doctor retrieves them with a long, ultrasound-guided needle, inserted via the vagina. The needle, which is connected to a pump, pokes through the vaginal wall and punctures the ovary to get to the follicles. The pump gently suctions out the contents, which usually include an egg.

In classic IVF, the egg is then put, with sperm, in a glass dish. Once fertilized, it is placed back in the original woman’s body. The only difference with egg donation is that the fertilized egg goes into another woman’s body.

The very first IVF baby was born in 1978, and it took doctors only a few years to realize that another woman’s eggs would do just as well. Suddenly, pregnancy was a possibility for women whose eggs had been destroyed by chemotherapy or illness, older women whose eggs were no longer viable and women whose eggs were unusable for reasons no one understood; it also made parenthood a possibility for gay men. Egg donation was revolutionary.

After the eggs are retrieved, the woman’s body is supposed to go back to normal within a week or two. Often, that’s exactly what happens. But sometimes it’s not. OHSS—the condition that Anna had twice—is one of the more serious possibilities. There are some factors that make a woman more likely to get OHSS: being young, having polycystic ovaries, having more than twenty eggs develop at once and having high estrogen levels on the day of the trigger shot, to name a few. But it’s not easy to predict why it happens to some women and not others.

No one knows precisely how OHSS unfolds, but a chemical signal known as vascular endothelial growth factor, or VEGF, seems to play a key role. Importantly, VEGF makes blood vessels more permeable, allowing fluid to seep out. The seeped fluid then pools in a woman’s abdomen, causing her to look as though she’s many months pregnant. It can also collect around her lungs, making it hard for her to breathe. The seepage causes her blood to get thicker, increasing the chance of a clot or stroke. As well, reduced blood flow can damage her kidneys. In extremely rare cases, women can die from OHSS.

Up to a third of women who undergo ovarian stimulation will suffer “mild” OHSS, according to guidelines on managing the syndrome that were published jointly by the Society of Gynecologists and Obstetricians of Canada and the CFAS in November 2011. The mild form causes bloating and abdominal pain, but tends to go away on its own.

“Moderate” OHSS involves bloating, pain, nausea, vomiting and fluid buildup. “Sonja” thinks she may have had moderate OHSS her first time donating. “I was curled up on my bed,” she told me. “I was in so much pain. I had never felt anything like that. I was just sick to my stomach and in a lot of pain.” She walked hunched over for the next few days. Still, within a week, with no medical attention at all, she started to feel better.

But, in some women, the symptoms snowball. Nausea is severe, abdominal pain unbearable. They stop urinating. The fluid keeps accumulating. Their ovaries become huge. In Anna’s first case, she had to have the fluid drained, and she took drugs to counteract the VEGF and to prevent a blood clot. The second time, doctors treated her with an albumin drip to restore her blood volume.

Many fertility doctors use words like “extremely rare” and “very unlikely” to describe the incidence of OHSS. Some of the women I interviewed confirmed that that’s what they’d heard when they first inquired about egg donation. Literature that donors receive underscores this idea. “Fortunately, this condition is extremely rare and almost never occurs in the severe form unless a woman becomes pregnant. Therefore, in the situation of oocyte [egg] donation, the donor virtually has no chance of developing this condition,” according to an info packet from one Canadian clinic. “With the medications used today, the chance of an egg donor developing OHSS is very unlikely,” claims the website of another.

One statistic commonly cited by clinics is that OHSS occurs in 1 to 2 percent of cases. But that number actually refers only to the risk for severe OHSS, according to the SGOC-CFAS guidelines. Moderate OHSS can happen in up to 6 percent of cases, the guidelines say. If there are about five hundred donations every year in Canada, as CARTR reports, then somewhere between five and thirty egg donors might suffer from this condition annually.

But even those numbers are only very rough estimates. They don’t come from studies on egg donors—they’re extrapolations from studies on IVF patients. Egg donors are different from IVF patients in important ways. For one thing, unlike IVF patients, they don’t get pregnant right after the eggs are removed. That should make them less likely to suffer OHSS, since pregnancy hormones are a major contributing factor in the condition. On the other hand, donors tend to be younger, and have many more eggs stimulated and retrieved, than women undergoing IVF, which may make donors more likely to get OHSS.

The incidence of OHSS among donors has not been widely studied, and, where it has, the findings vary. A Spanish study, looking through a single clinic’s records, found that, out of 4,052 egg donations, only twenty-two resulted in OHSS—just half a percent. A survey of 155 egg donors by the US-based Donor Sibling Registry, an online meeting place for donors and donor offspring, found that over 11 percent of respondents had to be hospitalized or treated due to OHSS. A UK study, looking to establish risk estimates for women donating eggs for research purposes, intensively followed 339 women whose retrievals produced twenty or more eggs. The study found that, if fewer than twenty eggs were retrieved, the risks were very small: 0.1 percent. But women who had twenty or more eggs retrieved had about a 14.5 percent chance of being hospitalized.

Several of the women I interviewed described their experiences with OHSS. “Leia,” for instance, had two bouts of the syndrome serious enough to require draining. “Heather” had to be drained after two of her donations. Most striking, though, was the case of “Melanie,” from Ottawa, whose problems mirrored Anna’s in several respects.

The same Toronto physician who oversaw Anna’s most recent donation had been Melanie’s doctor a few years before. Like Anna, Melanie lived far from the doctor treating her—in this case, a five-hour drive—and had a local physician perform the ultrasound monitoring while the Toronto doctor instructed her on drug dosage. Such women are sometimes referred to as “satellite patients,” and their care is complicated by the fact that part of the work is subcontracted to a second clinic for a small fee.

Again like Anna, when Melanie arrived at the Toronto clinic, the doctor discovered that she had a lot more eggs than anticipated. In Melanie’s case, there were thirty-six. She had been told to expect somewhere between five and eight.

Melanie was donating her eggs to a gay couple she had met on the internet, but she had also agreed to act as their surrogate and carry the embryos to term. Like Anna, she was doing it without pay. But getting pregnant would greatly increase the risk of OHSS, so the doctor decided to delay the embryo transfer. In Melanie’s chart, someone wrote, “at risk of OHSS.” Yet the doctor simply sent her home after retrieving the eggs, without alerting an Ottawa physician that she may need help or giving her the name of a local professional she could contact.

Before she left Toronto, Melanie started to feel sick. When she arrived home, she called the Toronto clinic and was told to go see a gynecologist. She did—and it was no small feat getting a same-day appointment—but the gynecologist didn’t know what to do. She told Melanie to go to the emergency room, where Melanie ended up waiting for seven hours, watching her stomach swell out. “I looked like I was fourteen months pregnant,” she said. “I was huge. I mean, huge.” But the doctors did some blood work and told her she was fine.

In tears, Melanie went to a different hospital and waited another few hours in its ER. Eventually she was admitted and treated for severe OHSS. “The back of my calf and my leg were touching each other, I was so swollen,” she remembered. “I actually had to have someone shower me because I could not do it—I couldn’t lift my arms. I couldn’t bend over. I couldn’t wipe my own butt. I couldn’t do anything.”

Melanie had trouble not only moving, but, according to hospital records, eating and breathing, too. She was given IV rehydration, four types of painkillers, and blood thinners and compression stockings to prevent a clot. She was in hospital for nine days.

Although predicting the onset of OHSS isn’t easy, doctors do have options to make it less likely. It’s well-known, for instance, that large numbers of eggs can cause OHSS. In the days leading up to a retrieval, if there are a worrying number of eggs, doctors can reduce how much follicle-stimulating hormone a woman is taking, a practice known as “coasting.” They can also prescribe a drug called Dostinex, which counteracts vascular endothelial growth factor. Or they can simply not give the trigger shot. Without that final shot, the eggs will not ripen and OHSS will not occur.

Unfortunately, all of these options come at a very high emotional—and sometimes financial—cost to the recipient. When fertility doctors make decisions about how many eggs to stimulate and what to do if there are too many, they have to weigh the needs of both donor and recipient—and the interests of the patients are sometimes at odds. More eggs give the recipient a better shot at pregnancy. But too many eggs increase the donor’s chance of suffering from OHSS.

Because it will influence how they manage donors’ care, it’s important for fertility doctors to recognize how many eggs is “too many.” But many are reluctant to take a position. I asked Carl Laskin, a former president of the CFAS, to poll Canada’s IVF medical directors on where they thought the line should be drawn, but they declined to answer because the limit varies from donor to donor. Although Laskin’s own view was that over twenty is too many, he made it clear that he wasn’t speaking for everyone. Indeed, at a recent annual meeting of the CFAS, one guest speaker said that thirty-six eggs is just fine.

At present, it is not even possible to know how many eggs Canadian fertility doctors actually retrieve. The numbers are not publicly available, and the doctors I’ve asked have declined to release their clinic statistics to me. Physicians usually tell donors that they hope to retrieve around twelve eggs. But of the fifty-two donations that I heard about in my interviews, only four yielded a dozen or fewer eggs, according to what the donors remembered being told. Some women thought they’d heard numbers in the thirties, forties or sixties.

When six of the donors I interviewed later requested medical records from their doctors, information about the number of eggs retrieved was sometimes missing. Only three of the fourteen files even contained a record of the surgical procedure the donors underwent to have their eggs removed. Every doctor knows that it is his or her legal obligation to provide full medical records to patients upon request. Yet when pressed with follow-up letters, Anna and Melanie’s doctor simply ignored them.

OHSS is not the only potential health risk of donation. Physicians usually warn donors about the possibility of problems like infection and vaginal bleeding, which are also considered rare. Three of the donors I interviewed described serious bleeding immediately following retrieval. “Meg” was hospitalized for a day after her fifth donation. For Leia, the problem came after her sixth. “I had this unexplainable bleeding,” she told me. “It just went on and on.” Her physician considered hospitalization, but instead treated her as an outpatient. “The doctor took the most fantastic care of me,” she said. But the bleeding persisted for sixteen days, at which point she saw a fertility doctor closer to where she lived, who prescribed more hormones.

After Sonja’s sixth donation, she never had a normal menstrual cycle again. “Everything just went haywire,” she said. “I eventually got to a point where I was having a period every two weeks.”

Despite the fact that her Toronto-area doctor had performed the last five of her six donations, Sonja never got to speak with him about the problem. At first, most of her communication with the clinic had to be channeled through the American agency that brokered the donation. After a few weeks of this, she was able to directly email the clinic nurse, who reassured her that the changes in her cycle couldn’t have anything to do with the donations. The doctor she saw in her hometown, in the US, felt the same way. “But he is a fertility doctor,” she laughed. “So, you know, you have to question some of the things he might say in regards to egg donation.”

Although she’ll never know for sure, Sonja believes that the bleeding was linked to the donation. “That happened immediately after the last donation,” she said. “So I don’t think that was a coincidence at all.” She put up with the bleeding for over a year and finally had an endometrial ablation—a procedure that burns away the lining of the uterus. She already had children of her own, but being made infertile disturbed her. “I can’t have any more children even if I wanted to,” she wrote at the time on her blog, I Am an Anonymous Egg Donor. “I don’t, but still. Not having control of that bothers me.” She was thirty years old.

The experience has made Sonja consider donors who haven’t had kids yet. “If you really want to help a family out, that’s a wonderful thing. But have your own family first,” she said. “It would be so sad if you helped another family to have children and then to find out later that you can’t have your own.” She thinks doctors should strongly discourage would-be donors who have not already had their own families.

The clinic’s staff never followed up with her, and Sonja has not told them about the ablation. “I don’t know what that would have done, really,” she told me. She had a strong bond with the doctor and the staff, whom she called “awesome.” She thinks they probably would have felt pretty bad. “They’re human,” she said.

A year after Melanie’s tangle with OHSS, the second of two attempted surrogate pregnancies failed to take; eighteen months after that, her menstrual cycles became unmanageably heavy. “I couldn’t go out. I couldn’t wear skirts. I was ruining chairs, bedding,” she said. “It controlled my life.” After suffering through it for two years, she finally, at age thirty-six, had a hysterectomy.

Anna had the opposite problem from Sonja and Melanie: no periods at all. When I caught up with her, about five months after her final donation, she told me she hadn’t resumed menstruating yet. “I’ve kind of realized how serious it is to be tampering with your reproductive system,” she said. She had recently gotten married and was hoping to have children. “What if it comes to the point where I have to use an egg donor?” she asked. She was just twenty-three.

Not long after, Anna was prescribed the drug metformin, often used to treat polycystic ovarian syndrome—a hormone imbalance that can cause irregular menstruation. Following her last donation, she developed symptoms of the disorder—acne, excess hair growth, weight gain—and was diagnosed with “mild” polycystic ovarian syndrome. The metformin seems to be helping, but it costs $40 per month, and her doctor says she will have to take it for the rest of her life.

A few years earlier, “Heather,” who’d had three ovarian stimulations, and two bouts of OHSS, had also been put on metformin. She was in her late twenties. It worked for a while, she told me recently, but now she gets only a few cycles per year.

These women’s menstrual changes may or may not be related to ovarian stimulation—it’s impossible to know. To illuminate whether donation increases the chance of erratic cycles and heavy bleeding, doctors need to undertake systematic, long-term follow-ups with donors.

Many donors specifically inquire about whether donation will affect their own future fertility. Doctors often respond by pointing out that a woman starts puberty with around four hundred thousand eggs and, in her lifetime, will ovulate about four hundred of them at most. As well, the eggs recruited in donation would have been shed that month anyway.

Overall, the message from some doctors tends to be reassuring: if no infection develops—and infection is rare—a donor’s fertility should be unaffected. But the experiences of Sonja, Melanie, Anna and Heather raise interesting questions. Of the eighteen women I interviewed, five reported permanent changes in their menstrual cycles following donation. That’s similar to the results of the Donor Sibling Registry survey, which found that 26 percent of donors later had menstrual changes or new infertility. Might ovarian stimulation alter a woman’s menstrual cycle, independent of normal aging? If so, how often do those alterations lead to treatments, like endometrial ablations and hysterectomies, that will render her infertile? Could menstrual alterations, like those that Anna and Heather experienced, make it more likely that they’ll have trouble conceiving when they want to have their own children?

These questions remain unanswered. No one has systematically looked into whether fertility is affected by donation. It would not be easy to do so—donors are typically young, so they would have to be followed for decades, and the scope of the study would have to be large. Anyway, no one has an urgent financial incentive to learn more.

Many women also wonder whether donation will increase their risk of cancer. Most fertility doctors say that there is no firm evidence that fertility treatments cause cancer, though some acknowledge that new data suggests a possible link. Some clinics don’t mention cancer in the informed-consent forms that women sign before donating.

Before donating eggs to her same-sex partner, “Mallory” asked her Vancouver fertility doctor about cancer. He’d smiled and said, “It’s worth the risk.” Four years later, at age thirty-six, she was diagnosed with Stage Three breast cancer, and endured months of chemo and radiation therapy. The cancer is now in remission. She never mentioned it to her fertility doctor and will never know if the disease was related to her ovarian stimulation.

The vast majority of women who get breast cancer have never taken fertility drugs or had their eggs retrieved. But there are reasons for concern, according to Louise Brinton, chief of the Hormonal and Reproductive Epidemiology Branch at the US National Cancer Institute in Rockville, Maryland, who studies the link between reproductive hormones and cancer. For one thing, ovulation itself is linked to both breast and ovarian cancers. It’s thought that the repetitive damage caused by the egg leaving the ovary each month—and the continual resultant cell repair—predisposes the ovary to tumour formation. (Women who spend a greater proportion of their reproductive lives pregnant have fewer ovulations and a lower incidence of certain cancers.) Women who undergo IVF not only have a lot of extra ovulations, but have multiple punctures to the ovary, too, which raises “additional concerns,” Brinton told me.

As well, stimulation drugs typically raise a woman’s estrogen levels to more than ten times that of a normal menstrual cycle. Estrogen is known to promote the development of breast and other cancers.

Though no one is tracking donors specifically, Brinton and other researchers have been studying large numbers of women who have undergone IVF. (Infertility is independently linked to cancer, so these studies are challenging.) Despite all the theoretical reasons for concern, most studies have been reassuring. Many, including some of Brinton’s, did not find that women who underwent ovarian stimulation were more likely to develop cancers of the thyroid, colon, cervix, ovary or breast. But Brinton warns that many women who have undergone ovarian stimulation have not yet reached the age when cancer typically appears.

Indeed, a few long-term studies are now beginning to find links. A large 2011 Dutch study found that, fifteen years on, women who had undergone IVF were twice as likely to have borderline ovarian malignancies than similarly infertile women who had not sought treatment, although the overall risk remains low. In early 2012, an Australian study found that women who had undergone IVF in their twenties—but not women who had done so in their forties—were more likely than expected to develop breast cancer. (This might be of import to donors, who tend to be young.) According to Brinton, several studies implicate fertility drugs in uterine cancers, which is not surprising, given that these cancers are known to be responsive to hormones. The risks of egg donation, Brinton said, “have not been fully vetted.”

Most fertility doctors will insist that egg donors are patients, and are treated with all attendant respect and care. Sadly, the evidence does not always bear this out. Sonja’s doctor, who had stimulated her ovaries five times in two years, did not make time to discuss the alarming change in her menstrual cycles, which showed up immediately after the final retrieval. Melanie’s doctor sent her home, knowing she was at risk of OHSS, without formally terminating his care of her or transferring her to another professional. He did the same thing to Anna a few years later. Some fertility doctors deny full medical records to donors. These are troubling examples of doctors failing to meet a standard of care set out by their own governing body, the College of Physicians and Surgeons of Ontario.

Some doctors barely disguise the fact that they see donors as less than full patients. In the process of donating, one woman learned that, at age twenty-three, she might have fertility issues of her own. The recipients, who were family friends, broke the news; the doctor apparently considered it more relevant to them than to her. When she wrote to complain, the doctor told her not to contact him again, but to send any complaints to his “quality control manager.”

What do doctors owe donors? To start with, they owe candour and clarity about the risks. According to Françoise Baylis, the Canada Research Chair in Bioethics and Philosophy, doctors have an ethical responsibility that goes beyond reciting statistics from the medical literature. When doctors say that the risk of OHSS is low—just 1 percent—what many donors hear is It won’t happen to me, she said. There are ways to be clearer. “Think about one of those big classes at university, with five hundred students,” she said. “Five people in there will get OHSS, and you might be one of them.” Above all, doctors owe donors full duty of care. “A woman going through as an egg donor is not a reagent off the shelf,” Carl Laskin said. “She is your patient.”

But fertility doctors have an unusual and serious conflict of interest. They have two patients—the recipient and the donor—and the interests of one often collide with the interests of the other. “Can a physician act in the best interest of both?” asked Vanessa Gruben, a law professor at the University of Ottawa. In a forthcoming paper, she argues that they may not be able to—and that such conflicts of interest need to be resolved.

In other areas of medicine that use donors, such as bone-marrow transplantation, physicians have taken steps to protect donors by separating their medical care from the care of the recipient. Applied to fertility medicine, this could mean giving the egg donor her own doctor, responsible only to her and keeping only her health in mind. A separate doctor could care for the recipient. Given that the recipient is the paying patient, however, this would be a challenging ideal to uphold in practice.

Egg donors deserve at least the same treatment as other patients—and, arguably, better. After all, they are young and healthy, and they undertake medical treatment for another person’s benefit. They deserve to know the truth about the health risks they face, and, wherever possible, to have those risks reduced.