We are all are passionate about our chosen clinical interests. Our team has a unique blend of experiences which we use to best serve our patients, as well as our local and online communities. 

Each endocrinologist in the ERH Associates group has their own sub-specialties. Some of us have expertise in children's hormone health (paediatric endocrinology), others in gender-affirming medicine, hormone issues in pregnancy, PMS/premenstrual dysphoric disorder, and men's hormone health (andrology).

Endocrine doctors (endocrinologists) are specialists in hormones and the glands that produce them. Endocrinologists can help with keeping healthy in relation to the hypothalamus, pituitary, thyroid, parathyroid glands, reproductive hormonal health, bone health and adrenal glands.

We are all qualified endocrinologists, with particular expertise in reproductive health. We can help with problems relating to absent or irregular periods, menopause, polycystic ovarian syndrome (PCOS), variations in sexual characteristics (VSDs), and testosterone replacement.

Meet the team: 

Our philosophy is that excellent doctors can have a vibrant life outside of clinical medicine. Each of us has a variety of passion projects and interests that are energizing, creatively inspiring, and bring richness of personal experience to our medical practice, and sometimes surprisingly transferrable skills!

Matou Nei


Tena Koe



Stella Milsom

Clinical & Academic lead of ERH Associates
Subspeciality  expertise in menopause, PCOS, bone, paediatric endocrinology and VSCs.

Stella is a reproductive endocrinologist at National Women’s Hospital, and in private practice with the ERH Associates Group based at Fertility Associates, Auckland and clinical senior lecturer in the Department of Obstetrics and Gynaecology, University of Auckland.
Stella is on the Boards of Osteoporosis New Zealand and Human Fertility UK, is the previous Chair of endocrinology training in New Zealand for the Royal College of Physicians, is a member of the National Health Committees formulating guidelines on menopausal hormone therapy and fertility preservation and is an advisor to Pharmac. She is a member of WHISPA group – a medical advisory board to High Performance Sport New Zealand. Her clinical and research interests include lactation physiology,  ovulatory disorders, especially polycystic ovary syndrome (PCOS) and hypothalamic amenorrhea.

Interesting facts: Stella played the clarinet and formerly dreamed of becoming a professional musician. Stella juggles her various clinical and academic commitments with  managing several agriCultural farms together with her cardiothoracic surgeon husband.


MbChB, Dip Obs, FRACP





Business director of ERH Associates
Subspeciality expertise in menopause, PCOS, athlete hormone health. PMS/PMDD, VSCs and gender-affirming medicine.

Megan completed her endocrinology training in Auckland and then undertook a fellowship in London at St Bartholomew's and University College of London Hospitals. Since returning to New Zealand, Megan has worked in both general and reproductive endocrinology at Fertility Associates and at Auckland District Health Board, and now for number of years in the ERH Associates group based at Fertility Associates.
Megan has particular reproductive endocrine interests in menopause, polycystic ovarian syndrome, gender-affirming care, as well as athlete hormone health and energy deficiency. Megan is involved in WHISPA (a medical advisory board to High Performance Sport New Zealand) and is on the medial board of Talk Peach (a charity for gynaecological cancer). 

Interesting facts: Megan has a Speech and Drama degree from Trinity College of London and is a seasoned public Speaker. She loves skiing and most of all loves being organised by her three daughters. 





Susannah o'sullivan

Susannah completed her training as an endocrinologist at Auckland and Greenlane hospitals in 2008 when she joined Fertility Associates to work in the areas of general and reproductive endocrinology, with particular interests in polycystic ovarian syndrome, menopause, and osteoporosis.
Following completion of a PhD in Medicine, Susannah took up a post as a senior lecturer in Pharmacology at the University of Auckland, where she is also involved in clinical and scientific research with a particular focus on bone health throughout life.

interesting facts: Susannah enjoys long-distance running and is something of a mathematical whiz who could have been a forensic accouNtant in a another life...  



NOTE: Susannah is currently not accepting new referrals in private. Referrals Addressed to Susannah will be RE-Directed to one of the other endocrinologists


Subspeciality expertise in menopause, PCOS, gender-affirming medicine, and bone disorders.



Director of Digital Projects at ERH Associates.
Subspeciality expertise in menopause, PCOS, PMS/PMDD, VSCs and endocrine issues in pregnancy.

After graduating from the University of Auckland and completing specialist endocrine training in Auckland in 2015, Sasha undertook a post-graduate fellowship in General and Reproductive Endocrinology in London at Homerton Hospital and University College of London Hospital.
Sasha has experience in general and reproductive endocrinology and with endocrine problems in pregnancy. Her areas of particular interest include PCOS, variations in sexual characteristics (VSCs), PMS/premenstrual dysphoric disorder, premature ovarian insufficiency and hypothalamic amenorrhoea. 






Subspeciality expertise in public health, andrology and the endocrinology of pregnancy.

Maritza completed training as an endocrinologist in 2016 and moved to Seattle, WA with her family. She worked as a visiting academic scholar at the University of Washington (UW) and co-authored several papers in the area of hormonal male contraception (HMC). Maritza completed a Master of Public Health (Global Health) at UW in 2020 and worked with a group of researchers studying HIV in Kenya. 
Maritza brings a broad base of knowledge to her endocrinology practice – both research and clinical experience – considering not only the issue at hand, but the broader factors that shape health and wellbeing. She enjoys all aspects of endocrinology, but particularly women's health. 

interesting facts:
during the COVID-19 pandemic maritza worked as a senior public health advisor for Microsoft corporation in the United states.
She enjoys hiking with her two dogs and spending time at piha beach.




Scientific Publications

As part of our philosophy to contribute to the evidence base for medical care, and we have collaborated together on a number of research projects as well as working with other research groups nationally and internationally.

Media Features

In keeping with our mission to empower you with information about your endocrine and reproductive health, our endocrinologists  feature in print and film interviews for public education.

Medical research

Public education




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SErvices & resources

Find out more about what we do