Growth Before Birth: The Relationship between Placental Weights and Infant and Maternal Health in early-twentieth century Barcelona

By Gregori Galofré-Vilà (Universitat Pompeu Fabra and Barcelona Graduate School of Economics) and Bernard Harris (University of Strathclyde)

R. Alcaraz, Maternitat, Ayuda al desvalido. Available at Wikicommons.

It is now widely accepted that early-life conditions have a significant effect on lifelong health (see e.g. Wells 2016).  Many researchers have sought to examine intrauterine health by studying birth weights, but the evidence of historical changes is mixed.  Although some researchers have argued that birth weights have increased over time (e.g. O’Brien et al. 2020), others have found little evidence of any significant change over the course of the last century (Roberts and Wood 2014).  These findings have led Schneider (2017: 25) to conclude either that, ‘fetal health has remained stagnant’ or that ‘the indicators used to measure fetal health … are not as helpful as research might hope’.

The absence of unequivocal evidence of changes in birth weight has encouraged researchers to pay more attention to other intrauterine health indicators, including the size and shape of the placenta and the ratio of placental weight to birth weight (e.g. Burton et al. 2010).  The placenta transfers oxygen and nutrients from the mother to foetus and provides the means of removing waste products.  Although the evidence regarding changes in placental weight is also mixed, it has been described as a ‘mirror’ reflecting the foetus’ intrauterine status (Kaur 2016: 185).

Historical studies of changes in placental weights are still very rare.  However, we have collected data on almost 4000 placentas which were weighed and measured at Barcelona’s Provincial House (La Casa Provincial de Maternitat i Expósits) between 1905 and 1920.  Our new paper (Galofré-Vilà and Harris, in press) examines the impact of short-term fluctuations in economic conditions on placental weights immediately before and during the First World War, together with the relationship between placental weights and other maternal and neonatal health indicators and long-term changes in placental weight over the course of the century.

Our first aim was to compare changes in birth weight with changes in placental weight.  As we can see from Figure 1, there was little change in average birth weights, but placental weights fluctuated more markedly.  In our paper, we show how these fluctuations may have been related to changes in real wage rates over the same period.

Figure 1. The development of birthweight and placental weight, 1905-1920. Source: as per article. Note: The dark blue line shows the monthly data and the red lines show the yearly averages with their associated 95 percent confidence intervals.

These findings support claims that the placenta is able to ‘adapt’ to changing economic circumstances, but our evidence also shows that such ‘adaptations’ may not be able to counteract the impact of maternal undernutrition entirely.  As Figure 2 demonstrates, although most neonatal markers show a reverse J-shaped curve (a higher risk of perinatal mortality with premature or small-for-gestational-age births), the relationship between placental weight and early-life mortality is U-shaped.

We also control for maternal characteristics using a Cox proportional hazards model.  Even if increases in placental weight can be regarded as a form of ‘adaptive response’, they are not cost-free, as both very low and very high placental weights are associated with increased risks of early-life mortality.  These findings are consistent with David Barker’s conclusion that elevated placental weight ratios lead to adverse outcomes in later life (Barker et al. 2010).

Figure 2. Early-life Mortality, Birthweight, Birth Length, Placental weight and BW:PW ratio. Source: as per article.

We have also compared the average value of placental weights in the Provincial House with modern Spanish data.  These data suggest that average placental weights have declined over the course of the last century.  However, the data from other countries are more mixed.  Placental weight also seems to have declined in Finland and Switzerland, but this is less obvious in other countries such as the United Kingdom and the United States.

Overall, whilst placental weights may well provide a sensitive guide to the intrauterine environment, we still know relatively little about the ways in which they may, or may not, have changed over time.  However, this picture may change if more historical series come to light.

To contact the authors: 

Gregori Galofré-Vilà, gregori.galofre@upf.edu, Twitter: @gregorigalofre

Bernard Harris, bernard.harris@strath.ac.uk

References: 

Barker, D. J. P., Thornburg, K. L., Osmond, C., Kajantie, E., and Eriksson, J. G. (2010), ‘The Surface Area of the Placenta and Hypertension in the Offspring in Later Life’, International Journal of Developmental Biology, 54, 525-530.

Burton, G., Jauniaux, E. and and Charnock-Jones, D.S. (2010), ‘The influence of the intrauterine environment on human placental development’, International Journal of Developmental Biology, 54, 303-11.

Galofré-Vilà, G. and Harris, B. (in press), ‘Growth Before birth: the relationship between placental weights and infant and maternal health in early-twentieth century Barcelona’, Economic History Review.

Kaur, D. (2016), ‘Assessment of placental weight, newborn birth weight in normal pregnant women and anaemic pregnant women: a correlation and comparative study’, International Journal of Health Sciences and Research, 6, 180-7.

O’Brien, O., Higgins, M. and Mooney, E. (2020), ‘Placental weights from normal deliveries in Ireland’, Irish Journal of Medical Science, 189, 581-3.

Roberts, E., and Wood, P. (2014), ‘Birth weight and adult health in historical perspective: Evidence from a New Zealand Cohort, 1907-1922’, Social Science and Medicine, 107, 154-161.

Schneider, E. (2017), ‘Fetal health stagnation: have health conditions in utero improved in the US and Western and Northern Europe over the past 150 years?’, Social Science and Medicine, 179, 18-26.

Wells, J.C.K. (2016), The metabolic ghetto: evolutionary perspectives on nutrition, power relations and chronic disease, Cambridge: Cambridge University Press.

Sanitary infrastructures and the decline of mortality in Germany, 1877-1913

by Daniel Gallardo Albarrán (Wageningen University)

The full article on this blog has been now published for The Economic History Review and it is available for free on Early View for 7 days, at this link

M0011720 The main drainage of the Metropolis
Wellcome Collections. The main drainage of the Metropolis. Available at

Lack of access to clean water and sanitation facilities are still common across the globe.  Simultaneously,  infectious, water-transmitted  illnesses are an important cause of death in these regions. Similarly, industrializing economies during the late 19th century exhibited extraordinarily high death rates from waterborne diseases. However, unlike contemporary developing countries, the former experienced a large decrease in mortality in subsequent decades which meant that deaths from waterborne diseases were totally eradicated.

What explains this unprecedented improvement? The provision of safe drinking water is often considered a key factor. However, the prevalence of waterborne ailments transmitted through faecal-oral mechanisms is also determined by water contamination and/or the inadequate storage and disposal of human waste.  Consequently, doubts remain about efficacy of clean water per se to reduce mortality; this necessitates  an integrative analysis considering both waterworks and sewerage systems.

My research adopts this approach by considering the case of Germany between 1877 and 1913 when both utilities were adopted nationally and crude death rates (CDR) and infant mortality rates (IMR) declined by almost 50 per cent.  A quick glance at trends in mortality and the timing of sanitary infrastructures in Figure 1 suggests that improvements in water supply and sewage disposal are associated with better health outcomes. However, this evidence is only suggestive: Figure 1 only presents the experience of two cities and, importantly, factors outside public health investments — for example,  better nutrition, improved infant care — may account for changes in mortality To study the link between sanitary improvements and mortality more systematically, I examine two new datasets containing information on various measures of mortality at city level (overall deaths, infant mortality and cause-specific deaths) and the timing when municipalities began improving water supply and sewage disposal.

Picture 1
Figure 1: Mortality and sanitary interventions in two selected cities. Source: per original article. Note: The thick and thin vertical lines mark the initial year when cities had piped water and sewers.

The first set of results show that piped water reduced mortality, although its effects were limited given the absence of efficient systems of waste removal. Both sanitary interventions account for (at least) a fifth of the decrease in crude death rates between 1877 and 1913. If we consider the fall in infant deaths instead, I find that sewers were equally important in providing effective protection against waterborne illnesses, since improvements in water supply and sewage disposal explain a quarter of the fall in infant mortality rates.
I interpret these findings causally because both interventions had a persistent short-term impact on mortality instantaneously following their implementation, not before. As Figure 2 shows, CDR and IMR immediately decline following the construction of both waterworks and sewerage, and mortality exhibits no statistically significant trends in the years preceding the sanitary interventions (the reference point for these comparisons is one year prior to their construction). Furthermore, using cause-specific deaths I find that sanitary infrastructures are strongly associated with enteric-related illnesses, and deaths from a very different set of causes — homicides, suicides or accidents — are not.

Picture 2
Figure 2: The joint effect of water supply and sewerage over time. Source: per original article. Note: Figures show the joint effect of two variables capturing the existence (or lack thereof) of waterworks and sewerage over time on CDR and IMR. The vertical bars are 90 percent confidence intervals. The reference year (-1) is one year prior the coded.

The second set of results relates to the heterogeneous effects of sanitary interventions along different dimensions. I find that their impact on mortality are less universal than hitherto thought, since their effectiveness largely depended on local characteristics such as income inequality or the availability of female employment.
In sum, my research shows that the mere provision of safe water, is not sufficient to explain a significant fraction of the mortality decline in Germany at the turn of the 20th century. Investments in proper waste removal were needed to realize the full potential of piped water. Most importantly, the unequal mortality-reducing effect of sanitation calls for a deeper understanding of how local factors interact with public health policies. This is especially relevant today, as international initiatives, for example, the Water, Sanitation and Hygiene programmes led by UNICEF, aims to of promote universal access to sanitary services in markedly different local contexts.

To contact the author:

daniel.gallardoalbarran@wur.nl

Twitter:  @DanielGalAlb

Missing girls in 19th-century Spain

by Francisco J. Beltrán Tapia (Norwegian University of Science and Technology)

This article is published by the Economic History Review, and it is available here

Gender discrimination, in the form of sex-selective abortion, female infanticide and the mortal neglect of young girls, constitutes a pervasive feature of many contemporary developing countries, especially in South and East Asia and Africa. Son preference stemmed from economic and cultural factors that have long influenced the perceived relative value of women in these regions and resulted in millions of “missing girls”. But, were there “missing girls” in historical Europe? The conventional narrative argues that there is little evidence for this kind of gender discrimination. According to this view, the European household formation system, together with prevailing ethical and religious values, limited female infanticide and the mortal neglect of young girls.

However, several studies suggest that parents treated their sons and daughters differently in 19th-century Britain and continental Europe (see, for instance, here, here or here). These authors stress that an unequal allocation of food, care and/or workload negatively affected girls’ nutritional status and morbidity, which translated in worsened heights and mortality rates. In order to provide more systematic historical evidence of this type of behaviour, our research (with Domingo Gallego-Martínez) relies on sex ratios at birth and at older ages. In the absence of gender discrimination, the number of boys per hundred girls in different age groups is remarkably regular, so comparing the observed figure to the expected (gender-neutral) sex ratio permits assessing the cumulative impact of gender bias in peri-natal, infant and child mortality and, consequently, the importance of potential discriminatory practices. However, although non-discriminatory sex ratios at birth revolve around 105-106 boys per hundred girls in most developed countries today, historical sex ratios cannot be compared directly to modern ones.

We have shown here that non-discriminatory infant and child sex ratios were much lower in the past. The biological survival advantage of girls was more visible in the high-mortality environments that characterised pre-industrial Europe due to poor living conditions, lack of hygiene and the absence of public health systems. Subsequently, boys suffered relatively higher mortality rates both in utero and during infancy and childhood. Historical infant and child sex ratios were therefore relatively low, even in the presence of gender-discriminatory practices. This is illustrated in Figure 1 below which plots the relationship between child sex ratios and infant mortality rates using information from seventeen European countries between 1750 and 2001. In particular, in societies where infant mortality rates were around 250 deaths (per 1,000 live births), a gender-neutral child sex ratio should have been slightly below parity (around 99.5 boys per hundred girls).

pic 01
Figure 1. Infant mortality rates and child sex ratios in Europe, 1750-2001

 

Compared to this benchmark, infant and child sex ratios in 19th-century Spain were abnormally high (see black dots in Figure 1 above; the number refers to the year of the observation), thus suggesting that some sort of gender discrimination was unduly increasing female mortality rates at those ages. This pattern, which is not the result of under-enumeration of girls in the censuses, mostly disappeared at the turn of the 20th century. Notwithstanding that average sex ratios remained relatively high in nineteenth- century Spain, some regions exhibited even more extreme figures. In 1860, 54 districts (out of 471) had infant sex ratios above 115, figures that are extremely unlikely to have occurred by chance. Relying on an extremely rich dataset at the district level, our research analyses regional variation in order to examine what lies behind the unbalanced sex ratios. Our results show that the presence of wage labour opportunities for women and the prevalence of extended families in which different generations of women cohabited had beneficial effects on girls’ survival. Likewise, infant and child sex ratios were lower in dense, more urbanized areas.

This evidence thus suggests that discriminatory practices with lethal consequences for girls constituted a veiled feature of pre-industrial Spain. Excess female mortality was then not necessarily the result of ill-treatment of young girls but could have been just based on an unequal allocation of resources within the household, a circumstance that probably cumulated as infants grew older. In contexts where infant and child mortality is high, a slight discrimination in the way that young girls were fed or treated when ill, as well as in the amount of work which they were entrusted with, was likely to have resulted in more girls dying from the combined effect of undernutrition and illness. Although female infanticide or other extreme versions of mistreatment of young girls may not have been a systematic feature of historical Europe, this line of research would point to more passive, but pervasive, forms of gender discrimination that also resulted in a significant fraction of missing girls.

To contact the author:

francisco.beltran.tapia@ntnu.no

Twitter: @FJBeltranTapia

Revisiting the changing body

by Bernard Harris (University of Strathclyde)

The Society has arranged with CUP that a 20% discount is available on this book, valid until the 11th November 2018. The discount page is: www.cambridge.org/wm-ecommerce-web/academic/landingPage/EHS20

The last century has witnessed unprecedented improvements in survivorship and life expectancy. In the United Kingdom alone, infant mortality fell from over 150 deaths per thousand births at the start of the last century to 3.9 deaths per thousand births in 2014 (see the Office for National Statistics  for further details). Average life expectancy at birth increased from 46.3 to 81.4 years over the same period (see the Human Mortality Database). These changes reflect fundamental improvements in diet and nutrition and environmental conditions.

The changing body: health, nutrition and human development in the western world since 1700 attempted to understand some of the underlying causes of these changes. It drew on a wide range of archival and other sources covering not only mortality but also height, weight and morbidity. One of our central themes was the extent to which long-term improvements in adult health reflected the beneficial effect of improvements in earlier life.

The changing body also outlined a very broad schema of ‘technophysio evolution’ to capture the intergenerational effects of investments in early life. This is represented in a very simple way in Figure 1. The Figure tries to show how improvements in the nutritional status of one generation increase its capacity to invest in the health and nutritional status of the next generation, and so on ‘ad infinitum’ (Floud et al. 2011: 4).

fig01
Figure 1. Technophysio evolution: a schema. Source: See Floud et al. 2011: 3-4.

We also looked at some of the underlying reasons for these changes, including the role of diet and ‘nutrition’. As part of this process, we included new estimates of the number of calories which could be derived from the amount of food available for human consumption in the United Kingdom between circa 1700 and 1913. However, our estimates contrasted sharply with others published at the same time (Muldrew 2011) and were challenged by a number of other authors subsequently. Broadberry et al. (2015) thought that our original estimates were too high, whereas both Kelly and Ó Gráda (2013) and Meredith and Oxley (2014) regarded them as too low.

Given the importance of these issues, we revisited our original calculations in 2015. We corrected an error in the original figures, used Overton and Campbell’s (1996) data on extraction rates to recalculate the number of calories, and included new information on the importation of food from Ireland to other parts of what became the UK. Our revised Estimate A suggested that the number of calories rose by just under 115 calories per head per day between 1700 and 1750 and by more than 230 calories between 1750 and 1800, with little changes between 1800 and 1850. Our revised Estimate B suggested that there was a much bigger increase during the first half of the eighteenth century, followed by a small decline between 1750 and 1800 and a bigger increase between 1800 and 1850 (see Figure 2). However, both sets of figures were still well below the estimates prepared by Kelly and Ó Gráda, Meredith and Oxley, and Muldrew for the years before 1800.

fig02
Source: Harris et al. 2015: 160.

These calculations have important implications for a number of recent debates in British economic and social history (Allen 2005, 2009). Our data do not necessarily resolve the debate over whether Britons were better fed than people in other countries, although they do compare quite favourably with relevant French estimates (see Floud et al. 2011: 55). However, they do suggest that a significant proportion of the eighteenth-century population was likely to have been underfed.
Our data also raise some important questions about the relationship between nutrition and mortality. Our revised Estimate A suggests that food availability rose slowly between 1700 and 1750 and then more rapidly between 1750 and 1800, before levelling off between 1800 and 1850. These figures are still broadly consistent with Wrigley et al.’s (1997) estimates of the main trends in life expectancy and our own figures for average stature. However, it is not enough simply to focus on averages; we also need to take account of possible changes in the distribution of foodstuffs within households and the population more generally (Harris 2015). Moreover, it is probably a mistake to examine the impact of diet and nutrition independently of other factors.

To contact the author: bernard.harris@strath.ac.uk

References

Allen, R. (2005), ‘English and Welsh agriculture, 1300-1850: outputs, inputs and income’. URL: https://www.nuffield.ox.ac.uk/media/2161/allen-eandw.pdf.

Allen, R. (2009), The British industrial revolution in global perspective, Cambridge: Cambridge University Press.

Broadberry, S., Campbell, B., Klein, A., Overton, M. and Van Leeuwen, B. (2015), British economic growth, 1270-1870, Cambridge: Cambridge University Press.

Floud, R., Fogel, R., Harris, B. and Hong, S.C. (2011), The changing body: health, nutrition and human development in the western world since 1700, Cambridge: Cambridge University Press.

Harris, B. (2015), ‘Food supply, health and economic development in England and Wales during the eighteenth and nineteenth centuries’, Scientia Danica, Series H, Humanistica, 4 (7), 139-52.

Harris, B., Floud, R. and Hong, S.C. (2015), ‘How many calories? Food availability in England and Wales in the eighteenth and nineteenth centuries’, Research in Economic History, 31, 111-91.

Kelly, M. and Ó Gráda, C. (2013), ‘Numerare est errare: agricultural output and food supply in England before and during the industrial revolution’, Journal of Economic History, 73 (4), 1132-63.

Meredith, D. and Oxley, D. (2014), ‘Food and fodder: feeding England, 1700-1900’, Past and Present, 222, 163-214.

Muldrew, C. (2011), Food, energy and the creation of industriousness: work and material culture in agrarian England, 1550-1780, Cambridge: Cambridge University Press.

Overton, M. and Campbell, B. (1996), ‘Production et productivité dans l’agriculture anglaise, 1086-1871’, Histoire et Mésure, 1 (3-4), 255-97.

Wrigley, E.A., Davies, R., Oeppen, J. and Schofield, R. (1997), English population history from family reconstitution, Cambridge: Cambridge University Press.

Patterns of rural infant mortality

By Paul Atkinson (University of Liverpool) – research conducted at Lancaster University thanks to ERC funding.

This work looked at the variation in infant mortality across time and place in country districts of England and Wales between 1851 and 1911. It used statistical methods to find patterns in the data from nearly 90% of rural places to show that, far from being one undifferentiated whole, the countryside was divided into zones with their own infant mortality trends. Broadly, infant mortality in the 1850s was worst in an eastern zone of England, but improved fastest here; across a large zone of south and central England infant mortality was somewhat lower than in the first zone in the 1850s (especially in the far south), but dropped somewhat more slowly; while in northern and western England, and in Wales, infant mortality began at lower levels than the rest of the country but stagnated or even increased, above all in the remotest districts.

 

How infant mortality changed in seven clusters of Registration Districts: for their locations, see map. The eastern zone is made up of Fenland and Mercia; Wessex, Severn and Trent form the south-central one and Health and Moor and Upland the final zone.

pic1

pic2

The obvious question is what made these patterns? Mainly different factors from the ones operating in towns, where the combination of crowding and poor sanitation made diarrhoeal disease the major killer, and where falling fertility was associated with decreasing infant mortality. This research identified statistically three other factors associated with infant mortality across time.

First, maternal health – plainly a factor in towns as well, but partly masked there by stronger influences. This work confirms – using a much larger dataset – Millward and Bell’s finding that the mortality of females from tuberculosis at reproductive ages, a good indicator of their general health, predicted infant mortality, explaining about a quarter of the variation in it. So, what makes mothers sick makes babies sick: probably poor nutrition above all, though we could not test that directly.

Second, maternal education, again relevant in towns too, but obscured there. Horrell, Oxley and Humphries have shown how a disadvantaged status within the household for women could produce excess female mortality: the research extends this argument to their babies. Literate women had higher status and more access to resources including food. What makes mothers vulnerable – in our study, their illiteracy – makes babies vulnerable. Female literacy predicted about a sixth of the variation in infant mortality.

The third factor linked with rising infant mortality in this period was remoteness, measured as the distance from the centre of each district to London. This was not just a characteristic of very remote locations, but applied at all distances above 100km. Exactly why infant mortality in the remotest places improved most slowly – even went backwards until the 1890s – is not very clear. This research argues that it was a mixture of large-scale out-migration stripping regions of their healthier inhabitants; possibly, the gradual way new ideas about infant care may have diffused from the biggest cities into the country, and, probably, features of rural social organisation: we argue elsewhere that the general trend to force women out of the agricultural labour market across the later nineteenth century was excluding them from forms of labour which benefited their status, and their babies’ welfare, in northern and western upland, pastoral farming areas, but harmed them in the arable south and east.

This amounts to an argument for two things: attention to ‘the mother as medium’ when explaining infant mortality rates, and attention to the diversity and particularity of local economies and cultures as we study the countryside of the past.

 

The full paper is available here

To contact the author: @PaulAtk43202349