Dennis Bonham was head of the postgraduate school of obstetrics and gynaecology at the National Women’s Hospital, Auckland, New Zealand. He was born in London on 23 September 1924, the son of Alfred John Bonham, a chemist, and Dorothy Alice Bonham, a pharmacist. He was educated at King Edward VI School, Nuneaton, and Sidney Sussex College, Cambridge. He then went to University College Hospital for his clinical training and for junior posts. He spent three years in the RAF at Fighter Command headquarters at Bentley Priory and then returned to University College to work with Nixon, researching into polycystic ovarian syndrome and the use of Schiller’s iodine in carcinoma of the cervix. In 1962 he was seconded to the British perinatal mortality survey as the obstetrician and co-authored its report with Neville Butler. In December 1963 he went to New Zealand as head of the postgraduate school of obstetrics and gynaecology in the University of Auckland. There, over the next 25 years, he made huge contributions to medicine and perinatal outcome, marked by an 80 per cent fall in perinatal mortality. He established the Foundation for the Newborn and the New Zealand Perinatal Society, and was adviser to WHO, receiving the gold medal from the Federation of Asia and Oceania Perinatal Societies. He went out of his way to encourage women into his specialty, setting up job-sharing training schemes. In 1990 he was involved in a controversial study into carcinoma of the cervix, which led to a national outcry, an inquiry and his censure by the New Zealand Medical Council. He married Nancie Plumb in 1945. They had two sons, both of whom became doctors. A big man, with colossal energy, he had many interests, notably sailing on the Norfolk Broads and New Zealand coastal waters, garden landscaping, building stone walls and designing terraced gardens. He was a passionate grower of orchids, becoming president, life member and judge of the New Zealand Orchid Society. He was awarded the gold medal of the 13th World Orchid Conference in 1990. He died in Auckland on 6 April 2005.