Arvo Ylppö (1887–1992) made a leading contribution to Finland's achievements in child healthcare in the 20th century

Finland is renowned for providing comprehensive, high-quality child healthcare, through specialised clinics and schools, which are affordable or free of charge. Multiple factors such as innovative services, improved nutrition and hygiene, family policies and medical advances have contributed to the country's low infant mortality rate. A crucial step in this process was the first maternity and child health clinics, which were established in the 1920s by Dr. Arvo Ylppö, when Finland was classed as a poor and largely agricultural-based society. He strongly believed that the best way to improve a nation's health was to focus on children from all socioeconomic backgrounds in every part of the country (Figure 1). Arvo Ylppö was born in October 1887. He was the fifth of 12 children and his parents ran a farm in Akaa, Finland.1 He started his medical studies at the University of Helsinki in 1906, but it had insufficient resources to teach anatomy. Ylppö and a small group of students visited Göttingen in Germany in 1908 to study this discipline. That was where he met Professor Friedrich Merkel (1845–1919), an anatomist who was to have a strong influence on his career and research.1 Ylppö was keen to pursue doctoral research when he completed his medical degree, but Professor Wilhelm Pipping (1854–1926) could not offer him a position in Helsinki. Instead, he decided to train and specialise as a paediatrician. He contacted Professor Leopold Langstein, Director of the Kaiserin-Auguste-Viktoria Haus in Berlin, and enrolled as a medical trainee in 1912. A few months later, Ylppö was assigned the topic for his doctoral thesis, which was bilirubin metabolism in newborn children, and he became the first to demonstrate the enterohepatic circulation of bilirubin. He completed his research in 1913 and in 1914 he defended his thesis and sat for his official medical exam, both in Helsinki.1-3 Although Ylppö achieved international acclaim for studying the pathological anatomy of children, his work did not receive the recognition and appreciation it deserved in Finland. He continued his career in Germany and spent 9 years working on the children's ward at the Kaiserin-Auguste-Viktoria Haus. He also published research on physiology, growth and clinical findings, pathology and the mortality and outcomes of premature infants.1 He was Head of Department from 1918 to 1920 and proved a popular and inspirational leader, whose sound professional judgement instilled great confidence in his colleagues. Ylppö was offered numerous university appointments in paediatrics in several countries, including the USA, but he wanted to return to Finland. In 1920 he was appointed lecturer and docent in paediatrics at the University of Helsinki and was responsible for the paediatric unit in the Department of Obstetrics. A year later, he received a personal professorship in paediatric diseases and rose to full professor of paediatrics at the University when Professor Pipping retired in 1925. His teaching focused on public health and enhancing the patient counselling skills of municipal doctors. Ylppö was chief physician of the University's Children's Clinic from 1920 to 1963, originally named Lastenlinna or Children's Castle Hospital, and also worked as a private paediatrician in the city. The hospital was the only one in the region and a wooden incubator, with hot sand in the base, was developed to move newborn infants and premature babies to the facility. The design was used until 1960, when more hospitals equipped with modern incubators were opened. This resulted in shorter travel times. As an administrator, Ylppö was instrumentally involved in setting up the new building of the Helsinki Children's Hospital, whose inauguration was delayed until 1946 due to war and postwar difficulties.3 The war almost led to catastrophic consequences for thousands of sick Finnish children. Their sanatoriums were used for treating the wounded during the Winter War, which started in November 1939, when Finland was invaded by the Soviet Union, and ended in March 1940. The few children's hospitals were overcrowded and even Ylppö's hospital was unable to admit severely ill children. Ylppö was a member of the Ministry of Social Affairs' Child Transfer Committee and helped to evacuate more than 20 000 weak and sick children to Sweden in 1942. Ylppö's main research output was during his years in Berlin. He showed that illness and death in premature children was not simply due to immaturity, which was the popular belief at the time. He showed that these outcomes could be prevented by treating diseases and this led to major advances in neonatology. For example, feeding premature infants at the Kaiserin-Auguste-Viktoria Hospital with breast milk resulted in remarkable decreases in infant mortality. He championed early enteral nutrition in premature infants being multiple decades ahead his time. The results of this practice in terms of decreased premature mortality were not improved upon until 1972.1, 4 Ylppö initiated training courses for public health and children's nurses in Finland in the 1920s in association with three nurses who qualified in Berlin. In 1922, he established a new type of clinic at the original Children's Castle Hospital, which emphasised prevention rather than cures. The free clinics provided medical checks and practical advice on health and childcare. From 1944, every community in Finland was legally required to open a well-baby clinic.5 The theme of improvement through innovation continued in 1938 with the introduction of a free baby box, which contained useful items and health promotion messages for Finnish mothers. The contents may have changed, but more than 95% of mothers still choose the baby box instead of an equivalent cash grant. Ylppö became heavily involved in cross-party political discussions about improving children's health and living conditions. He used his position as Chairman of the Mannerheimer League for Child Welfare, from 1920 to 1960, to spearhead efforts to enhance healthcare and maternal counselling.1 Ylppö was adept at using the media to reach his target audience and his lectures and popular science articles were highly effective in raising public awareness and interest. Ylppö built effective links between his clinic and the Finnish pharmaceutical industry in 1925 and championed the need for effective medicines as a public priority. He was also a member of the Orion Corporation's administrative body and contributed to developing new medicines to bring both health and economic benefits to Finland. In 1919, Ylppö received the prestigious Heubner Prize, awarded every 4 years for the best German language research work in medicine, for developing tables for acid–base assessments. The President of Finland granted him the title of Archiat, the highest recognition for a physician, which he held from 1952 until his death. In 1964, he received the Swedish Rosén von Rosenstein Medal, a prestigious global prize that is only awarded to three physicians every 5 years. A postage stamp honouring Ylppö was issued on his 100th birthday (Figure 2) and a commemorative 10 Euro silver coin was issued to mark his 125th birthday. His name was also given to a Finnish medal commending paediatricians of exceptional merit after he became one of the first recipients in 1957. In 1978, Ylppö was awarded the German Federal Cross of Merit for his contribution to infant survival. Ylppö was the epitome of a hard-working and enthusiastic paediatrician. He played cards, kept an exquisite art collection and his favourite pastimes were outdoor pursuits, including fishing. Ylppö married twice and fathered six children. He officially retired in 1957 and published his autobiography in 1964, entitled, My life between small and large. Ylppö died in 1992 at the age of 104 and is buried in Helsinki.1, 2 Ylppö's hard work, dedication, curiosity and collaboration advanced paediatrics and improved childcare. His work as a clinician, teacher, researcher and administrator for over almost half a century had a profound influence on children's health and survival. Between 1915 and 1920 the infant mortality rate in Finland was 114 deaths per 1000 live births. By 2023, it had fallen to 1.4, making it one of the lowest in the world. This is a clear measure of the contribution of driven, dedicated and outstanding people and one of the most important was Arvo Ylppö. Stefan Kutzsche: Conceptualization; investigation; writing – original draft; methodology; validation; writing – review and editing; supervision; resources. Allan G. A. Coombes: Investigation; writing – original draft; methodology; validation; writing – review and editing; resources. None. None.