Fanny Balmer, the daughter of Margaret McIntosh and her husband, William Balmer, a corporal in the 65th Regiment, was born in Auckland, New Zealand, on 21 August 1861. Her father died in 1869. After her mother remarried in 1871 Fanny and her family moved to Marton, and then around 1879 to the Turakina Valley. Little else is known about her early life.
On 1 July 1880 Fanny Balmer married Henry Joseph McHugh, a farmer in the Turakina Valley. They were to have six children. Although she helped her husband on the farm, Fanny also acted as a midwife and nurse to the local residents, and in 1893 she opened the Turakina general store. By 1904 her husband is thought to have died and the family had moved to Manaia. Fanny McHugh was registered as a midwife on 24 January 1906 and by 1907 had established The Bungalow maternity home at Manaia. She ran this with the help of her daughter, Gladys.
Gladys married in 1913 and when the First World War began in 1914 Fanny's five sons enlisted. Perhaps feeling that she had no family obligations, Fanny McHugh joined the New Zealand Volunteer Sisterhood. This had been established by Ettie Rout to nurse and care for sick soldiers, initially at Trentham Military Camp, and later in Egypt. By 1918 she was in London working alongside Adelaide Ballantine (also from Taranaki) doing street patrol work with the YMCA. The patrols were initiated to prevent the transmission of venereal disease by attempting to dissuade women and men, particularly those who were drunk, from engaging in licentious activities. The methods used by McHugh and other volunteer sisters differed from those of Rout, who was now also in London. They disapproved of Rout's advocacy of practical prophylaxis, while Rout thought the patrols' work, though admirable, was completely ineffective.
After the war Fanny McHugh returned to New Zealand and was appointed as a health patrol with the Department of Health. The legislation under which the patrols were created had been put in place in 1917 and the first appointments were made in 1919. Two women were placed in Auckland, Christchurch and Dunedin and one in Wellington to 'advise and warn' women about the dangers of venereal disease. From about 1921 McHugh worked in Auckland and then in Wellington, where she patrolled picture theatres, parks, beaches, tram-stops and wharves to protect women and children from sexual harassment or molestation and to discourage young couples from engaging in sexual activity. She also conferred with and advised other health patrols on their duties. Although this period was marked by widespread anxieties about racial fitness and the threat posed to the health of the nation by degenerate behaviour and debilitating disease, the patrols were merely a token attempt by the Health Department to grapple with the problem. McHugh's pleas for more staff, better funding and increased support were ignored. In a report to the department in 1923 she commented, 'Surely our girls are worth saving? They are the future mothers of the race.'
However, by this time it was already clear that head office was keen to phase out the patrols. This was probably due to problems with funding and mixed responses from women's groups. Nevertheless, because the department considered propaganda methods to be more effective than practical patrol work, the services of McHugh, who had experience in giving lectures, were retained while other patrols were dismissed in 1922.
Fanny McHugh remained with the Health Department as a social hygiene lecturer and health patrol until 1926, when she travelled to Canada to visit two of her sons. In her latter years she lived with her daughter, Gladys, at Thames. She died on 17 December 1943 at St Stephen's Hospital, Bombay, Auckland. Although the work for which she was more widely known was done during and after the First World War, McHugh had striven to enhance the health and welfare of women for nearly half a century.