Graceful, powerful and quick, Hazel Ouwehand surges through the water – among the world’s fastest butterfly sprinters.
Having already dipped under the qualifying time for the Glasgow Commonwealth Games in July, she’s shaping up as a genuine medal prospect in the 50m butterfly.
But behind theblocks, the record-setting swimmer and full-time accountant has quietly dealt with intensely painful periods and heavy bleeding, at times so severe that she couldn’t get out of bed or would pass out from the pain.
Ouwehand, 26, is now a strong advocate for open conversations around menstruation, particularly with coaches and other athletes, and has built a support network around her, both medical and holistic, to help her continue competing at the highest level.
This week, she returned to competition at the Australian Open championships in Brisbane, claiming silver in her preferred event. She was fresh from three weeks of altitude training in Flagstaff, Arizona, with the help of the $30,000 Yvette Williams Scholarship she was awarded last year.
She’s now turning her focus to a solid training block leading into the New Zealand swimming championships in May and chasing the qualifying mark in the 100m butterfly for Glasgow.
Hazel Ouwehand: "There were moments throughout the session where the pain would come in waves."
Since being diagnosed with endometriosis, which affects more than 10% of women and girls in New Zealand, Ouwehand has had surgery and now manages the pain and heavy periods with a hormonal IUD. But through her late teens, she struggled with her symptoms, not knowing the cause.
With a high pain tolerance and refusing to let it define her, she kept swimming.
“Even on day one and two of my period, I would probably still train. But there were moments throughout the session where the pain would come in waves. I might have had to sit on the wall for a moment … and breathe through that wave of pain until it went away,” the Paris Olympian and Birmingham Commonwealth Games athlete recalls.
“I would soak through a super tampon and a nighttime pad in the space of an hour for the first two days. It was awful.”
Her older sister experienced the same symptoms, which helped Ouwehand realise her periods weren’t normal. When her sister was diagnosed with endometriosis, the family understood generations of women in their family had probably suffered too.
Hazel Ouwehand celebrates after setting a new national record in the 50m butterfly. Photo / Simon Watts, BWMedia
As well as heavy bleeding, Ouwehand experienced intense pain. “It didn’t matter if I had a wheat pack and took ibuprofen and paracetamol – it just didn’t really help. There were a few instances where I passed out from the pain.”
She never pulled out of a competition due to her period. “The vast majority of the time, as soon as I was up on the blocks … as soon as I [dived] in the water, almost all of that pain just disappeared.
“Your mind is kind of numb to it because it’s focused on what you’re there to do. And I wasn’t there to be in pain and feel sorry for myself. I was there to race and do well.”
Ouwehand has never felt embarrassed talking to her coaches about her periods. Her current coach, David Lyles, has worked with female swimmers around the globe, and treating menstrual cycles as part of training isn’t foreign to him, Ouwehand says. “Whenever I’ve had conversations with him about my period, it’s just a conversation. It’s not this taboo thing.”
At 18, when Ouwehand left the small Waikato settlement of Te Pahū to join the high-performance environment in Auckland, she talked with sports doctor Lynne Coleman about her symptoms, which all pointed to endometriosis. But the only definitive way to diagnose the chronic disease is through laparoscopic (keyhole) surgery.
With major competitions looming, Ouwehand wasn’t ready for the invasive surgery and the recovery time needed, so she chose to go on the contraceptive pill to stop her periods.
“I skipped them for about two-and-a-half years, and I didn’t have any issues. And at that time in my life, it was exactly what I needed.”
Vanessa Ouwehand in the AON Swimming New Zealand National Open Swimming Championships at the National Aquatic Centre in Auckland. Photo / Simon Watts, BWMedia
During the Covid lockdowns, when swimmers were out of the pool, Ouwehand decided to have keyhole surgery to detect and remove endometriosis. She also had a Mirena IUD inserted to prevent further symptoms, and eased back into training within three weeks.
Five years on, Ouwehand says the surgery and the Mirena have made a “phenomenal” difference. “I still get a period, but it’s really tiny … in one menstrual cycle, I bleed a tablespoon at most.”
She’s now onto her second Mirena, replacing it after competing at the world championships in 2023. “My periods were starting to get a little more painful because the hormones from the Mirena wear off after time.”
She expects to have the IUD replaced again after the Commonwealth Games. “So hopefully my periods will go back to pain-free. There’s no way to know if the endo has grown back for me unless they do another laparoscopy, but I feel that’s unnecessary at this point.”
She knows she may need further surgery if the endometriosis has returned. But for now, the pain is at a level she can live with and compete with.
Dr Helen Fulcher, a specialist female health doctor at High-Performance Sport New Zealand, says that, because the symptoms of endometriosis – where cells that usually line the uterus end up in different parts of the body – are so wide-ranging and individual, there’s no specific formula to treat it. Even reaching a diagnosis can be a long journey.
Dr Helen Fulcher: "For female athletes, it's really important to not be fearful."
“Some symptoms of endometriosis won’t impact some people … for others, it’s so debilitating they really can’t get on with their life. No one should ever be putting up with problems that are really impacting or stopping them thriving in their life.
“When female athletes are trying to use their bodies to do the incredible things they do, those symptoms can get in the way of their job. The type of uniforms they’re wearing, having to leave a training session to change a pad, tampon or cup; being able to push through some of the symptoms or shift their training to adapt.”
Female athletes should be made to feel comfortable speaking with their coach or manager about difficulties with their periods, Fulcher says.
“I think there’s deep value in being able to say, ‘Actually, I know when my periods are coming, I know when I have my most significant symptoms, I want to be able to push harder at certain times.’
“For female athletes, it’s really important to not be fearful that this will reduce their performance. Most people can get up and perform through phenomenal difficulties when they need to. But in the daily training environment, making adaptations if you need them is really important.”
Surrounding herself with medical and holistic support has been “beyond beneficial” to Ouwehand, and talking to other female athletes and comparing experiences has also helped.
“It boils down to open and honest communication. Starting the conversation, talking with your friends, your sisters, your mother and other women who have experienced periods – be they normal, be they not. Because no woman’s experience is exactly the same,” she says.
“Some of us have endometriosis or PCOS, and maybe we didn’t know for a while that was why our periods were the way they were. But then someone tells us, ‘No, that’s not normal. You have this’, and you have that ‘Oh my gosh’ moment – I didn’t need to be experiencing all this pain.”
Swimming under the 50m butterfly qualifying time back in February for the Glasgow Games, soon after a stint of altitude training in China, was part of Ouwehand’s strategy.
“It was fantastic. I always planned to do it early because the opportunity to qualify is nationals in May, and I didn’t want to leave it till then.”
Ouwehand clocked 25.70s at the Waikato summer long course meet, under New Zealand’s A standard qualifying time of 25.83s. Her national record, set last year, stands at 25.43s – a second off Sarah Sjostrom’s world record.
Hazel Ouwehand in action at the 2025 Apollo Projects New Zealand Swimming Championships. Photo / Photosport
Although her goal was to go under the 50m butterfly qualifying time again in Brisbane this week, she was relatively happy with her time of 26.13s, finishing second to Australian Olympian Alex Perkins.
“Funnily enough, I did the exact same time in my heat as I did in my final down to the millisecond, which is very, very rare. We’re racing one week down from altitude, and it’s typical to have a lagging period afterwards. So we’re testing it to see how it feels, to then use that data in future.”
The Yvette Williams Scholarship, to support her training through to the Commonwealth Games, has been phenomenal, Ouwehand says. Although she works for Auckland accountancy firm Baker Tilly Staples Rodway, she still needs financial help to fund her travel.
“It’s been immensely and unbelievably helpful. Without it, I wouldn’t have been able to go to the World Cups last year, altitude in China or Flagstaff. I’m extremely grateful to the amazing athlete that Yvette Williams was.”