The baby boom of 1920 has received less attention than that following the Second World War, and was for long thought to be a simple catching up of the marriages and births that the war had prevented, as part of a gradual return to normalcy. Yet this baby boom occurred with similar intensity in non-belligerent countries. Other lines of enquiry thus need to be explored. In this article dealing with the large number of extra births registered in 1920 in Norway, a country that was neutral during the war, Svenn-Erik MAMELUND examines the hypothesis, sometimes proposed but never verified, concerning an influence of the Spanish flu epidemic of 1918 on the decline in fertility in 1919 and its strong upswing in 1920. This particularly virulent epidemic is known to have touched nearly a quarter of the world's population and to have caused between five and ten times as many deaths as the war. Because influenza was a notifiable disease in Norway, the author is able to examine on a monthly and regional basis the influence on fertility of the morbidity and mortality attributable to the flu. He concludes that the flu pandemic was indeed the main cause of the Norwegian baby boom of 1920 and suggests that it probably had a similar influence in other countries.
The European countries that were massively affected by the First World War, whether by sending soldiers to the front, fighting the war on their own soil, or both, experienced a sharp decline in fertility during the period 1914-1918 (Chesnais, 1992). Figure 1 shows a steep decline of fertility in Italy, France and Germany during the war. The fertility curves for other warring nations, for example Austria-Hungary, England and Wales, Scotland, Ireland, and Bulgaria, not shown, were very similar. The low fertility in the belligerent countries during the war is probably explained by the separation of soldiers from their wives and by the war having hindered young adults from marrying. In addition, it is reasonable to assume that those who were not enrolled in the armed forces postponed marriages and births from fear of the war and its consequences. The war thus created a huge potential for a compensating later resurgence in marriages and births as well as a "moral obligation to replace the deceased". Indeed, birth rates in most belligerent countries began to rise once again in 1919 (for France in 1917), so that by 1920 they had equalled or surpassed the pre-war level.
The fertility patterns of nations that remained neutral, Norway, Sweden, the Netherlands, Denmark, Switzerland and Spain, were not affected in the same way (Chesnais, 1992). Figure 2 shows that the birth rates in Norway, Sweden, and the Netherlands declined relatively smoothly and continuously throughout the war until 1919. (The pattern of these countries is also reasonably representative of Denmark, Switzerland, and Spain.) This decline, however, is typical of the transition from higher to lower birth rates that have marked all societies throughout Europe. Hence, no substantial decline in birth rates linked to the war seems to have occurred in neutral countries. Nonetheless, like the belligerent countries, neutral countries faced a baby boom in 1920 (Figure 2).
Surprisingly, there are few studies that have analysed the baby boom in Europe after the First World War in any depth, in contrast to the more famous baby boom following the second World War. Perhaps a natural explanation for the 1920 baby boom, especially for the warring nations, was the gradual return to normal patterns of life after the war (Henry, 1966; Winter, 1977). Yet despite this, the birth rates in 1919 seem to be far lower than pre-war figures. Could there have been other factors at that time to cause people to postpone the start of a family? There is also a clear discrepancy between birth rates in 1919 and those of 1920 that perhaps goes beyond the most immediate explanation, namely the First World War.
This article directs attention to a hitherto little appreciated factor, the Spanish influenza pandemic. …