When Catherine Fonesca volunteered as an egg donor, the intake form asked for her SAT scores.

It did not ask if she understood the long-term health implications of stimulating her ovaries to produce a bumper crop of eggs to be extracted and turned over to an infertile couple.

That wasn’t an oversight by the clinic. No one knows the long-term risks to egg donors—if, in fact, there are any. Anecdotally, some women—Fonesca among them—said they experienced an array of health problems after donations, including ovarian cysts and endometriosis, a painful inflammatory disease that can cause infertility.

But there has been little research on the long-term outcomes for egg donors, who are often recruited on college campuses with the promise of tens of thousands in payments if they have particularly desirable characteristics, such as green eyes or high-level tennis skills or Ivy League degrees.

“The bottom line is that we simply don’t know anything for sure, because nobody has followed these women systematically,” said Linda Kahn, a postdoctoral fellow at New York University School of Medicine.

The Centers for Disease Control and Prevention last year began requiring fertility clinics to report a wealth of information about egg donors, including their age, height, weight, ethnicity, and history of previous donations.

The CDC already collected data on short-term complications from egg donation. The expanded data set will give officials far more insight into those issues, including the first data on whether donating eggs multiple times puts a woman at increased risk of ovarian hyperstimulation syndrome, which can cause painful symptoms and in rare cases can be fatal.

But it still won’t address long-term risks.

Most of the research conducted on egg stimulation and extraction has focused on women undergoing in vitro fertilization, or IVF. It’s the same procedure as an egg donation. But the populations are different. Most women undergo IVF because they are infertile. Often, that infertility is a symptom of other health problems.

Donors, by contrast, are chosen precisely because they don’t have such health problems.

“I think it’s fair to say that they’re not the same population,” said Dr. Richard J. Paulson, president of the American Society for Reproductive Medicine and a specialist at the University of Southern California’s Keck School of Medicine. “I think that it is a valid point that we do not have very good long-term follow-up,” he said.

The one study on egg donors is a 2005 survey of 80 women who had donated eggs as long as two decades earlier. Thirteen of them said they were still experiencing physical effects that they attributed to the donation—things like ovarian cysts, fibroids, and infertility issues that arose later in life. But it was a small and unscientific sample, with no medical records to back up the women’s claims.

The dearth of solid data frustrates and enrages Dr. Wendy Chavkin, a professor of public health and obstetrics and gynecology at the Columbia University Mailman School of Public Health and cofounder of Global Doctors for Choice, a reproductive health advocacy group.

“To be going out there and using these procedures in a widespread manner violates every aspect of public health policy. ”

Egg donation nearly doubled from 2000 to 2010, when there were more than 18,000 donor cycles in the US, according to a study published in the Journal of the American Medical Association. The CDC reported that the number of donor cycles was 20,481 in 2014, the most recent year for which data is available. Experts predict the number will continue to rise as more women decide later in life to have children.

Chavkin argues that it’s not responsible to do so many procedures without more data.

“To be going out there and using these procedures in a widespread manner violates every aspect of public health policy. You’re supposed to have proof of efficacy, ethicality, proof of no other route,” she said. “Maybe donating is great, and a big boon, and consequences are minimal. But we don’t know.”

A swollen abdomen and a pounding heart

It was a cold February morning in 2014 when Catherine Fonesca walked into Reproductive Medicine Associates of New Jersey. She was there for the final step of egg donation—the egg retrieval process. For weeks, Fonesca had been injecting herself with hormones to nudge her ovaries to produce more eggs. By day 10 of pricking her stomach with a hormone-laden needle, her abdomen had swollen so large that she couldn’t fit into her pants.

Most donors produce somewhere between 10 and 25 eggs, which are then sucked out of their fallopian tube with a hollow needle inserted through the vagina. Fonesca’s ovaries had produced no less than 59 eggs.

Every one of those eggs would become the property of the Portuguese couple who chose Fonesca as their donor for her lustrous dark hair, big, bright brown eyes and elegant, expressive brows—all features common in Portuguese ancestry.

Many women donate eggs for the money; compensation is commonly around $5,000 to $10,000, though it can range higher for those with the most desirable traits. Fonesca, who’s now 26, was motivated in part by altruism. She liked the idea of helping a couple conceive; she was in nursing school at the time of her donation, and also on the bone marrow registry.

Still, by the time she went to the clinic on that morning, she was ready for the swelling and injections to be over.

As it turned out, she still had a long road ahead. The nurse gave her Tylenol with codeine after the egg retrieval and sent her home, but a few hours later she was in the emergency room. Her waist, normally 28 inches, now measured 41. Typical ovaries are about the size of walnuts. Hers had swelled to the size of grapefruits, displacing her other organs.

The hormones made her estrogen levels skyrocket, and in turn her capillaries were leaking into her abdomen. All of this made her blood thicken, putting her at a high risk for clots and pushing her heart into overdrive.

Fonesca was experiencing ovarian hyperstimulation syndrome, or OHSS. For every 100 women who inject hormones to stimulate their ovaries, one or two are likely to experience it. Sometimes, it requires a simple draining procedure. Rarely, women die from it.

For Fonesca, it took six months before she started to feel normal again, but she said after the OHSS, she started experiencing other medical issues that weren’t previously a problem: ovarian cysts, cervical tumors, 25 pounds of extra weight. Most recently, she was diagnosed with endometriosis.

Fonesca and other egg donors are warned that hyperstimulation is a short-term risk. They’re also typically told about immediate psychological effects of donating genetic material, which the American Society for Reproductive Medicine describes as “complex.” Those cautions are spelled out in the informed consent documents that donors sign.

But there’s no information in those documents on potential long-term risks, because research is so sparse.

A 2011 study that followed 25,000 Dutch women for 15 years found that infertile women who went through IVF were four times as likely to get ovarian cancer much later in life than infertile women who didn’t have the procedure, though the likelihood is still very low.

But infertility already predisposes women to a number of health risks, said Chavkin. She said that data from IVF studies can’t be used to draw conclusions about all egg donor risks. “There’s only the one piece in common [between the groups], which is the original stimulation and the retrieval. After that, once the embryo is implanted, the IVF recipient is going to go under a number of other hormonal changes, including pregnancy,” she said.

There simply isn’t any long-term health information to give egg donors, Kahn said: “They’re signing an informed consent, but how informed can your consent be if we don’t have the information?”

She and Chavkin say there’s no incentive for anyone to study the health risks to egg donors because the system as it now stands seems like a win-win-win: Fertility clinics get business, egg donors are well-compensated, and infertile couples have a better chance to conceive a baby.

“A for-profit business has found a willing group of consumers and sellers and run with it,” Chavkin said.

Added Kahn: “There is no eagerness to find anything wrong.”

“The biggest thing egg donation did was scare me. I felt used.”

Fertility experts say that research hasn’t happened because of the way egg donors were originally perceived when IVF started over 30 years ago. Most of the focus was on the infertile couple seeking to conceive.

“The egg donor was sort of in the background,” said Paulson, of the American Society for Reproductive Medicine.

“Donors aren’t really patients in the normal sense of the word,” said Dr. Jim Toner, an Atlanta-based endocrinologist and clinical director of SART. “So [the CDC] did not build out a system that allowed reporting of the donor’s cycle itself.”

A repeat donor finds herself infertile

Janneke Parrish, 25, has donated eggs three times.

Or at least, she’s tried to.

Her first two donations went well. She received $4,500 in payment the first time. The second time, she only accepted coverage of her medical costs because she donated in the UK, which doesn’t allow women to receive compensation outside of medical costs.

The third time, she was in the midst of the preparatory blood tests when she got a shock. “They called and told me my hormone levels were lower than the woman interested in receiving my eggs,” she recalled. She was infertile.

Parrish doesn’t blame her early menopause on her two donation cycles. But she admits that it’s odd—her mother got pregnant at 38 and there are no instances of infertility in her family. “On one hand, I never intended to have children, but I didn’t want biology to force that on me,” she said.

Now a data analyst at Apple, Parrish doesn’t regret donating her eggs. She still remembers the ad that prompted her to first consider it, when she was an undergrad majoring in philosophy and religious studies. The couple was looking for someone who was 5’7”, with brown hair and brown eyes. “That was me,” said Parrish. “Because the woman looked like me, I put myself in her position. There was no reason I couldn’t do it, so I thought I would change someone else’s life.”

Parrish said she would donate again if she could, but she does want more research on the risks for egg donors.

“I think there should be more research on the long-term effects, but I also understand the difficulty in doing so, given both the anonymity and the fact that this is fairly recent, technology-wise,” she said. “It’s difficult to make an informed decision when there’s no knowledge of what potential consequences could be.”

“It’s difficult to make an informed decision when there’s no knowledge of what potential consequences could be.”

Both Parrish and Fonesca said they’ve relied on advocacy groups like We Are Egg Donors to connect with other women who have been through the procedure.

It was on the group’s message boards that Fonesca finally found some comfort. The most lasting trauma, said Fonesca, has been the psychological strain—another area where research is scarce. “The biggest thing egg donation did was scare me,” she said, her voice weighty with emotion. “I felt used.”

Fonesca has not been able to find out whether the couple who got her 59 eggs was able to conceive a child. She agreed not to contact the couple when she went through the procedure. But she can’t help but wonder about the fate of the eggs that cost her so much.

“I just want to know,” she said, “if it was worth it.”

Republished with permission from STAT. This article originally appeared on January 28, 2017