Fertility Rates in Cambodia: A Bumpy Road

INTRODUCTION

In little time, the reproductive perspectives of the world have gone from a fear of overwhelming overpopulation—the Population Bomb was published in 1968 (http://pinguet.free.fr/ehrlich68.pdf)—to our current situation characterized by a generalized fertility decline (Ehrlich and Holm, 1968). As far as human history can report, world population has kept increasing with the most dramatic increment occurring during the last 100 years or so. Recently, however, we started to observe a reversal of this process. Whilst worldwide, the population continues to increase, but at a much slower rate, many countries now have a number of births that do not sustain population replacement for reasons discussed below.

Studies of changes in fertility patterns in different populations over time have led to the concept of demographic transition (Kirk, 1996). This describes the process whereby a given population will transition from a condition of high fertility and high mortality to one of low fertility and low mortality under the effects of several factors (Vollset et al., 2020). The latter primarily includes a decrease in infant mortality and an increase in life expectancy (Vollset et al., 2020). Instrumental in this process are accesses of women to the work force, control of fertility by free access to contraception, as well as an increase of the burden and cost linked to raising children (Alkema et al., 2011; Kirk, 1996). Simultaneously, an increase in female education and a delay in childbearing also tend to restrict family size (Alkema et al., 2011). Progressive availability of contraceptives has been advocated as an important contributor to fertility’s demise (Aitken, 2024). Indeed, data suggest that family size preference declined while contraceptive use improved, particularly in Africa. Increased female labor force participation is another potential route to fertility decline in sub-Saharan Africa (Halli et al., 2023; Odimegwu et al., 2018). But the role of contraception (Requena et al., 2023) and liberal access to abortion (Fernández and Juif, 2023) in the current fertility decline is not recognized by all and remains debated, however (Fernández and Juif, 2023; Requena et al., 2023).

The progressive increase in world population has encountered accidents, however, or “speed bumps,” if you will, due to pandemic episodes, wars (Aitken, 2024) or climate changes. For example, in the Southwestern United States, the population abandoned villages in the Mesa Verde area because of climate changes (Cordell et al., 2007). Detailed reconstructions of precipitation based on tree rings analysis from five geographic subregions of Ancestral Pueblo occupation confirmed that migration of these ancient Americans was driven by weather changes (Schwindt et al., 2016).

In this context, one country, Cambodia, has had a particularly bumpy road of its own when it comes to fertility and population because of salient events in its history. These shifts in Cambodia’s population are the object of our review here.

ANCIENT CAMBODIA

Angkor, the ancient capital of Cambodia, has been one of the world’s largest premodern settlement complexes (9th–15th centuries of Christian Era [CE]) (Klassen et al., 2021). To this date, however, no comprehensive demographic study has been completed, and key aspects of Angkor’s population and demographic history still remain unknown.

The question of Angkor’s demographic growth has been a source of persistent speculation and controversy since the beginning of modern scholarship in the region. In the mid-19th century, the French naturalist Henri Mouhot provided one of the first detailed accounts of Angkor’s history for European audiences (Mouhot, 2016). The first reasonably systematic attempt to calculate the population of Angkor was undertaken by archaeologist Bernard-Philippe Groslier, who cautiously suggested a total population of 1.9 million for the whole region surrounding Angkor in the last half of the 12th century CE (Groslier, 1979). Angkor’s population took several centuries to reach its peak, which was achieved during the 12th century CE.

More conservative estimates have concluded that Angkor’s population amounted to 1 million people. Diachronic modeling— based on assessing development over time—of population within the medieval Greater Angkor Region settlement—is indeed complex.

Classically, one recognizes three distinct parts in the city complex, which grew at different rates. These are the civic ceremonial center (CCC), Angkor metropolitan area (AMA), and embankments (BANKs) (Klassen et al., 2021). During the earliest phases, the population growth rates within the three occupation zones were comparable. However, by the early 10th century CE—during the classical period—the population in AMA had nearly quadrupled, as illustrated in Fig. 1 (Klassen et al., 2021). Water management networks were crucial to Angkor development and survival and were instrumental to the prosperity of the city (Fletcher et al., 2008).

One of the critical questions regarding the emergence of urban systems is how the farming fraction of the population managed to generate sufficient food surpluses to feed the growing non-food- producing city inhabitants (Adams, 2017; Trigger, 2003). This question is especially salient for Angkor, Cambodia, one of the most spatially extensive preindustrial urban agglomerations documented by archaeology (Klassen et al., 2022). Recent research using a combination of airborne and spaceborne remote sensing techniques alongside ground surveys has revealed an urban area extending over at least 1,500km². As mentioned above, the total population is estimated to have exceeded 1 million at its apogee, which included more than 150,000 people in the densely populated core, AMA (Klassen et al., 2018) (Fig. 2) (Klassen et al., 2021). The global population needs for such an urban complex implied, therefore, a considerable surplus of production by farmers in order to feed a growing proportion of non-farming inhabitants.

Current data indeed suggest that Angkor had a significant non-food-producing population and that agricultural production was integrated into the overall system of social organization and physical infrastructure needed for overlooking water management and transportation (Klassen et al., 2018). Together, this evidence suggests that the large-scale organization of agricultural production within the area of urban infrastructure was the primary mechanism through which Angkor was able to sustain itself (Fletcher, 2009).

Remarkably, there were increasing returns in the outputs of agricultural temple communities rooted in the spatial distribution of farmers. This organization aimed at balancing costs and benefits. Spatial patterns in the properties of temple communities are consistent with the existence of an equilibrium between land value and transport cost at the scale of the whole metropolitan area. Thus, the internal structure of Angkor, a prototypical example of low-density agrarian urbanism, seems to have deployed mechanisms that are common to contemporary cities. Further, the combination of the spatial distribution of the urban landscape and the demonstrated increase in returns from labor indicates that agricultural production was incorporated in the urban economy (Klassen et al., 2022).

The decline of Angkor and its causes are subject to controversies. Some have proposed data supporting that severe climate changes disrupted the complex organization of this vast city and its irrigation system. These data indicate a protracted decline of population within the economic and administrative core of the city, rather than an abrupt demographic collapse. This also suggests that the focus of power began to shift toward new urban centers located outside of the capital, starting during the 14th century (Penny et al., 2019).

Conversely, Carter et al. suggest that the temple occupation at Angkor Wat was never completely abandoned (Carter et al., 2019). This implies that the mounds, or embankments, continued to exist until the 17th or 18th centuries (Carter et al., 2019), as remaining structures of the largest low-density urban complex of the pre- industrial world (Fletcher et al., 2003). Importantly for our discussion here, Angkor’s decline was linked to population displacements away from the former metropolitan area, but not to a sheer population shrinkage in the metropolitan population (Fletcher et al., 2003).

FERTILITY RATES IN CAMBODIA IN THE SIXTIES

Classically, fertility rates in Cambodia were similar to those of neighbor countries. Based on the 1958 demographic survey conducted in Cambodia (Dasvarma et al., 2002) and the 1962 Census (Desbarats, 1995), Desbarats estimated that total fertility rate (TFR) stood at approximately seven in 1962. These results were at par with those of Vietnam and similar to data emanating from the whole of Southeast Asia. At the same time, industrialized countries of Europe were starting to experience the beginning of a baby bust, which followed the notorious post-World War II baby boom (Artzrouni and Easterlin, 1982). This fall in birth rates, which was detected in the sixties and identified as a population transition phenomena, was encountered in many countries. These included France, Italy, and Great Britain, where it appears that the year 1964 represented a turning point in industrial development and concomitant decline in natality (Lindgren, 1971). The decrease in fertility has been logically associated with an increased aging of the population (Grundy, 1996).

MORTALITY AND FERTILITY

General correlation

TFR—the total number of children that would be born to each woman if she were to live to the end of her childbearing years (Aitken, 2022)—is the primary metric used for assessing population fertility. Today, the whole world is encountering a sharp decrease in TFR affecting nearly all countries, with several of them already below the population replacement level (Aitken et al., 2008).

Reduction of mortality—particularly, infant mortality—has traditionally been considered a necessary prerequisite for a long- term reduction of fertility during the process of demographic transition (Reher, 1999). According to this theory, societies go from high to low levels of fertility through a process during which mortality declines, followed after a short or long lag by fertility reduction (Reher, 1999).

The effect of infant mortality reduction on fertility is one of the main mechanisms stressed by recent publications for explaining the worldwide demographic transitions (Angeles, 2010). Based on analyses conducted in developing countries since 1960, infant mortality plays a large role in fertility reductions. According to these observations, changes in fertility behavior come with a lag of about 10 years (Angeles, 2010). The onset of the transition is characterized by a critical increase in life expectancy at birth. This marks the transitioning process from Malthusian growth to an equilibrium with investments in human capital and the possibility of long-run growth (Soares, 2005).

A recent review in the Lancet reported that over the past 20 years, fertility rates have dropped steadily and life expectancy increased, with few exceptions (GBD 2019 Demographics Collaborators, 2020). Demographic transition is a general process whereby populations go from high mortality and high fertility to low mortality and low fertility (GBD 2019 Demographics Collaborators, 2020). Schematically, five stages of the demographic transition have been proposed: before transition, early transition, mid-transition, late transition, and post transition (GBD 2019 Demographics Collaborators, 2020).

Recently, several countries have experienced a combination of low fertility and stagnating improvement in mortality rates, pushing more populations into the final stages of the demographic transition (GBD 2019 Demographics Collaborators, 2020). Late in the demographic transition, we ultimately see a crossover of crude birth rate and crude death rate where the evolution of population becomes negative (GBD 2019 Demographics Collaborators, 2020). As a result of the decline in fertility rates, half of all countries had reached below-replacement-level TFR in 2019, with 43 of these having reached an ultra-low TFR of 1.5 or lower (GBD 2019 Demographics Collaborators, 2020). Ultimately, sustained low fertility could hasten the number of countries encountering a shrinkage of their total population, as is already the case in Japan, China, and Korea.

The plague or Black Death

Links between mortality and pregnancy rates have not always been seen (Poos, 1981). An example is the legacy of the plague (DeWitte, 2014; Siuda and Sunde, 2021)—Black Death (Poos, 1981)—which extended through most of western Europe in the 14th century. The death toll eliminated approximately 25% of the entire population. In spite of the magnitude of this toll, the Black Death, however, was not followed by an increase in birth rates (Poos, 1981).

Generally speaking, there has never been a society in which fertility was high and mortality low, or mortality high and fertility low. The exceptions were only encountered in moments of epidemic, economic, or political stress and for relatively brief periods of time, or among very specific historic sub-populations (Reher, 1999). In each model, the total fertility rate falls as child mortality declines, and in turn, the number of surviving children increases.

There are also results suggesting that factors other than declining infant and child mortality may also cause a drop in net reproduction rates in industrialized countries (Doepke, 2005). These include access to the workforce (Alkema et al., 2011) and liberal availability of contraceptives (Alkema et al., 2011) and abortion measures (Aitken, 2024). The demographic transition observed in industrialized countries implies an important lagged time—several decades—from decreased infant mortality to decreased fertility. Others, however, suggest that causality runs from fertility to mortality (Hyndman and Ullah, 2007; Reher, 1999).

The classic theory used to explain the demographic transition positions infant mortality as a key explanatory variable influencing the decline in fertility. However, the empirical results obtained in what is known as the Princeton European Fertility Project have led many specialists to question this assumption (Sánchez-Barricarte, 2017). Others’ research based on individual data has, however, shown that it is the number of surviving children, rather than mortality, that is instrumental for reproductive decisions (Sánchez-Barricarte, 2017).

Local mortality spurs

The links between mortality and fertility have also been studied following unanticipated mortality shocks. It has notably been the case following the massive 2004 Indian Ocean tsunami (Nobles et al., 2015). This catastrophe killed large numbers of residents of some Indonesian communities but caused no deaths in neighboring groups. Using complex analyses, the authors identified a behavioral fertility response to mortality exposure (Nobles et al., 2015). There was indeed a sustained fertility increase in the areas affected by the tsunami, which appeared driven by two behavioral responses to mortality exposure. First, mothers who lost one or more children in the disaster were significantly more likely to bear additional children after the tsunami. Second, women without children before the tsunami-initiated family-building earlier than normal in communities where tsunami-related mortality rates were higher (Nobles et al., 2015).

Fertility trends following the World War II

The post-World War II era was characterized by a baby boom during which fertility rates increased substantially. Ultimately, the process vanished with a decrease in fertility, which started in the 60s (Doepke et al., 2005). The authors argue that female work had markedly increased during the war (Pillai et al., 1987) and that many women of the war generation continued to work after the war. This, to a certain extent, deterred younger women from joining the labor market and led them to rather choose to have more children instead (Doepke et al., 2005). The post-World War II baby boom also affected the Soviet Union and leveled off simultaneously as it did in the West (Raleigh, 2011).

THE 1975 TRAGEDY OF CAMBODIA

Cambodia like the rest of Southeast Asia (notably, Vietnam and Laos) was under the burden of years of war that followed the Japanese occupation during World War II. This certainly carried its share of pain and suffering, but did not significantly impact birth rates in these countries of former French Indochina. Unforeseen during the tumultuous years that affected the whole area, Cambodia encountered a completely new genre of drama, one of unprecedented magnitude since the Holocaust, which had a drastic and immediate impact on natality. A Marxist political regime, the Khmer Rouge, gained power in 1975. This primarily stemmed from dysfunctional measures taken by the United States. Indeed, the consequences of unabated—yet officially denied—bombing of Western Cambodia decided by Henry Kissinger and Richard Nixon gave the Khmer Rouge the support it would probably not have had otherwise. Ultimately, the Khmer Rouge gained control of the countryside and became the sole revolutionary movement capable of claiming power in Cambodia. This together with the CIA-led political coup that empowered the Khmer Republic headed by Long Nol gave the Khmer Rouge sufficient momentum to ultimately take control of the country. The Long Nol regime (1970–1975) progressively lost power over the countryside, which induced an increase in the population of the city of Phnom Penh, ultimately reaching nearly 2 million people. This process, however, bore little consequences on natality in Cambodia.

The unforeseen drama—the Khmer Rouge Revolution—took place on April 17, 1975, when the Khmer Rouge took control of the city of Phnom Penh after U.S. support came to an end. This event was first seen by the population as a joyful end of the long-lasting war. The freedom celebration was quickly over however. On the very first day—on April 17—the Khmer Rouge ordered an immediate evacuation of the city of Phnom Penh and started dispersing its swollen population on the roads of the whole country. This was initiated on the false claim that the city was going to be bombed by Americans with advice given to the population that they would return home in a few days. “You don’t need to take any bag,” said the young Khmer Rouge soldiers. Things unraveled differently however. The Khmer Rouge ultimately emptied the city of Phnom Penh and relocated the city people to the countryside with no return home in sight. These city inhabitants became the displaced or “new people,” as per revolutionary terminology. Ultimately their living condition generated famine, and they suffered extremely high mortality rates.

Documents, witness reports, and other evidences that have been collected indicate that there were waves of mass killings of specific groups of people (Gruspier and Pollanen, 2017). Those who survived were deliberately worked to death on farms or died of starvation. Heuveline reports the direct and indirect death tally that resulted from the Khmer Rouge revolution (Heuveline, 2001). The first cause of death corresponds to the stark increase in natural mortality and includes all biological causes of death that became more prevalent because of a combination of harsher environment (e.g., in Cambodia, malaria, sanitation in general), a weakened population (e.g., physical labor, food deficiency), and a near absence of medical remedies (Heuveline, 2001). The second cause of death corresponds to violent mortality, which in Cambodia included war casualties such as combat deaths, bombardment or mine victims, and executions. Combining all these events, the net result yields an estimate of 2.2 million excess deaths for the nearly 4 years of the Khmer Rouge regime, or 1/3 of the total population of Cambodia (Heuveline, 2001).

Under the Khmer Rouge, marriage rates dropped to about one-third of its prewar level, and birth rates fell drastically. The displaced people were clearly not in conditions that would lead them to have children, as they could barely feed themselves, and their existing children were dying of malnutrition. The Khmer Rouge revolution was an utopia aimed at erasing differences between people, which in their ideology, stemmed from the perversities of western civilization. Individual possessions were confiscated to the profit of the state—dubbed “Angkar” (The Organization)—and the use of currency abolished.

The actual achievements of the Khmer Rouge regime differed drastically from the announced objectives. The displaced or “new” people—prior inhabitants of cities primarily, Phnom Penh—were turned against the original villagers and treated differently. Eventually, this aggravated the grievances that would naturally exist between the groups of peasants and former city dwellers. The displaced, or “new” people, lived under the constant fear of being punished, beaten, executed, and/or perishing from under- nutrition. This situation of extreme—life-threatening stress affecting all—drastically differed from the misfortune of an everyday, or “ordinary” war that chronically gloomed the area during the 50s, 60s, and early 70s. Under the Khmer Rouge, the daily steps of everyday life—reproduction included—came to a standstill for most of the Cambodian population particularly, the “new” people. Importantly, the stresses and threats imposed on the Cambodian people were visible to all and present every day. This is a very different situation from what stems from a distant and not directly visible peril, such as a war that looms far away. The Khmer Rouge drama is thus unique in its direct and immediate impact on fertility, as is the rapid rebound in birth rates that has been witnessed when Cambodia was liberated. In a seminal publication, Heuveline reports on the “Phoenix” effect seen in the Cambodian population upon the expulsion of the Khmer Rouge after nearly 4 years (Heuveline and Poch, 2007). Heuveline’s data first provide quantitative evidence attesting to a profound decline of fertility during this Khmer Rouge down to 3.7 live births per woman in 1976–1978, which is markedly lower than its level before the civil war. Second, Heuveline also indicates that the fall of the Khmer Rouge regime when Cambodia was liberated was followed by a rise in the number of marriages. This was ultimately followed by a substantial rebound in birth, or “baby boom” effect, starting in the early days of 1979.

The fertility rebound, which peaked in the two years after the fall of the Khmer Rouge is quite striking, as illustrated in Fig. 3. According to Heuveline’s estimates, fertility rates increased to slightly over seven live births per woman for the 1979–1980 period, which was 91% more than during the preceding 1976–1978 period and 36% larger than the 1966–1970 level (Heuveline and Poch, 2007).

According to Heuveline again, these data validate the proposed relationship between infant mortality and fertility. The Cambodian data also support the suggested concept that for inducing a boost in reproduction, mortality changes must be effectively perceived by the population (Cohen and Montgomery, 1998). And it certainly was in the case of the Khmer Rouge drama, with $>2$ million people exiled from their city and their home nearly overnight.

The concept of genocide has been attributed to the violence committed by the Khmer Rouge (Heuveline, 2015), which resulted in the slaying of a third of the country’s population. Estimates based on physical evidence (e.g., bone remains) only focused on violent deaths. Beginning with a full mapping of mass grave pits conducted from satellite imagery, remote sensing, and ground-penetrating radars, this approach continues with interviews, and in some cases, forensic data to determine the time and cause of each death (Etcheson and Cheang, 2004). Violent deaths had previously been estimated from testimonies using respondents’ reported cause of death and apportioning the number of excess deaths between violent and non-violent causes (Marek, 1994; Meng-Try, 1981).

The seven existing estimates of violent deaths under the Khmer Rouge are widely scattered. The lowest three are in the order of 100,000 to 300,000 violent deaths, and the highest almost reach 1.1 million. The nine existing estimates of excess deaths—up and above violent death—range from 741,000 to 3.315 million. The highest figure is the only one based on a direct tally of excess-death reports. The average Cambodian population from 1960 to 2000 is illustrated in Fig. 4 (Heuveline, 2015).

That the Cambodian experience reveals a rapid and major impact on fertility in response to increased mortality as compared to the reproductive consequences of other dramas is consistent with Montgomery’s (1998) argument. This argument states that perceptions of mortality trends—unmistakable in Cambodia under the Khmer Rouge —is not necessarily perceived by the population in other situations. The mortality–fertility relationship, hence, appears asymmetrical in the case of the Cambodian drama.

Finally, the trauma inflicted by the Khmer Rouge regime also resulted in an important gender imbalance with a much larger death rate among males (Kogure and Takasaki, 2022). Indeed, other increases in mortality—as discussed for the Black Plague—were not followed by an increase in natality.

In short, under Pol Pot (Weltig, 2008), nearly a third of Cambodia’s eight million inhabitants perished from disease, overwork, starvation, and outright execution under this genocidal regime (Hinton, 1998). This is today remembered in the Tuol Sleng Genocide Museum in Phnom Penh. The museum is housed in the former Tuol Sleng prison, a detention and torture center through which thousands of people passed before execution at the Choeung Ek killing field (Brown and Millington, 2015).

WORLDWIDE FERTILITY DECLINE

TFR has been decreasing dramatically for decades in many countries (Fauser et al., 2024). By 2050, 77% of countries will have a TFR below the replacement level of 2.1 children per woman (Fauser et al., 2024). De Silva and Tenreyro (2020) reported that policies aimed at altering family-size norms accelerated and strengthened the decline in fertility, which would have otherwise taken place much more gradually. In 1960, more than half of the world countries recorded average fertility rates greater than six children per woman. By 2015, median TFR was 2.2 children per woman. The decline in mortality alone is not sufficient to explain the fall in fertility observed over the past few decades (De Silva and Tenreyro, 2020). Other issues, such as modernization of society and fundamental changes in social values, including the education and emancipation of women, also reinforced the decline in fertility (Aitken, 2024).

In the United States, this decline is led by falling birth rates for women under 30, and in recent years, even for women in their 30s. These declines will almost certainly result in women ultimately having fewer children than previous generations had (Stone, 2018). Controlling for marital status, fertility in the United States has been roughly stable for the past decade and a half (Stone, 2018). Most changes are attributed to the increasing delay in young people getting married. In other words, declining fertility actually primarily stems from delayed marriage (Stone, 2018). This trend cannot easily be reversed with “technological” or “technocratic” solutions.

A recent survey indicated that Sweden, like other Nordic countries, has encountered falling fertility rates (Neyer et al., 2022). According to these data, the fertility decline was confined to first births in couples. Remarkably, this decline was homogenous across socio-demographic groups and regions of residence. Data from the Generations and Gender Survey in 2021 further revealed that childlessness has a dire outlook on the future and stems from a lack of trust in institutions (Neyer et al., 2022). In East Asian countries, reviews indicated that the costs of rearing children are a primary factor limiting the number of births (Ogawa et al., 2009).

WORLD POPULATION SHRINKAGE: FIRST TIME EVER

The fertility decline that currently affects—to different extents—all countries of the globe is going to lead to a world population shrinkage after the increase in aging stabilizes. Is this impending population shrinkage the first ever to occur in mankind history? In the past, certain civilizations have undergone declines, but by and large, these have led to population displacements. There are however doubts as to whether the world population has ever undergone a long-lasting global reduction in the past as the one that is profiling on the horizon. Probably not. Indeed, a significant and lasting population decline has apparently never occurred in the 5,000 years of assessable mankind history.

Table 1 summarizes world population data on all four continents during the whole CE (Biraben, 1979) (64). As it can be seen, these data illustrate 2,000 years of uninterrupted population growth. At the outset of the CE, the world population was estimated at approximately 250 million. It progressively increased during the 2,000 following years to reach 6.1 billion by the year 2,000. This growth knew some speed bumps, however (Aitken, 2024), as encountered in Cambodia in the late 70s (as discussed above). These included the Black Death, the Thirty-Year War with Germany, the end of the Ming Dynasty in China, and ultimately, World War I and the ensuing Spanish Influenza epidemic, during which population growth momentarily slowed (Aitken, 2024).

By the year 2050, the world population is forecasted to reach 9.7 billion. This is however expected to be its maximum, after which a decline is expected in light of the profound decrease in fertility rates. Indeed, fertility rates are below replacement levels in an increasing number of countries, as detailed above, notably because of delayed childbearing and increased childless couples (Aitken, 2024). Also contributing are the increasing prosperity, female education, and changes in lifestyle (Aitken, 2022).

Japan is one of the most rapidly aging and depopulating countries in the world (Matanle, 2017). Government projections indicate that Japan may shrink 32% from the high of 128 million in 2008 to approximately 87 million already by 2060, due to a sustained fall in rates of human reproduction. Whereas in 1947 each woman expected to give birth in her lifetime to 4.54 children, this had dropped below the population replacement rate of 2.1 children per woman by 1974 and remained well below replacement at 1.39 children in 2010 (Matanle, 2014). An important population decline linked to decreasing fertility is currently also observed in China (Aitken, 2024). The lowest fertility of all is encountered in South Korea since 2001, with TFR currently below 0.7 (Hwang, 2023).

FERTILITY RATES IN MODERN CAMBODIA

The population in Cambodia increased from nearly 5 million at the time of independence in 1953 to nearly 20 million today (https://www.worldometers.info/world-population/cambodia-population/#google_vignette). Through this process, however, the Cambodian population shrunk by approximately 2 million people under the Khmer Rouge, as amply discussed above.

According to Hukin, Cambodia is now undergoing a fertility transition. Bridging over the Khmer Rouge drama, TFR in Cambodia fell from 6.7 before 1970 to 3.0 in 2010 and is associated with a parallel increase in population aging (Hukin, 2014). The Survey on Fertility and Contraception in Cambodia, conducted in 1994, looked at fertility rates. In 1995, Chhun Long et al. reported an estimated TFR of 4.9, 4.1, and 5.1, respectively for total, urban, and rural areas for 1990–1999 (Long et al., 1995). The mid-point of the reference period is June 30, 1993. The fertility estimates are based on birth history during the past 5 years and therefore can be regarded as direct estimates (Dasvarma et al., 2002).

In recent years, fertility decline has been affecting the whole of Asia (Gubhaju, 2007). Over the past 10 years, fertility rates in Cambodia have been at par with those of neighboring countries, Vietnam, for example. Indeed, there continues to exist in Cambodia and elsewhere a moderate, yet constant decline in TFR that, however, still remains for the time being just above replacement rate (Um et al., 2024) (Fig. 5). The median age at first marriage among women aged 15–49 is 21.5 years, an increase of one year as compared to 20.5 years in 2014. Life expectancy has remarkably increased in Cambodia, being today at 75.9 and 70.1 for women and men, respectively (GBD 2019 Demographics Collaborators, 2020).

Fertility treatments exist in Cambodia, where 35 years after the fall of the Khmer Rouge, a fertility clinic—Fertility Clinic of Cambodia (FCC)—opened. Since then, FCC has been thriving (de Ziegler et al., 2015).

CONCLUSION

Modern-day Cambodia has evolved from a remarkably startling history stemming from a flourishing period—Angkor was the largest known ancient city—to an unprecedented 20th-century drama, the Khmer Rouge regime. Cambodia survived both the dwindling of the Angkor civilization and mass killing during the Khmer Rouge. The excess deaths from outright killing and ensuing starvation under the Khmer Rouge led to a sharp decline in natality associated with the loss of nearly a third of the country’s population. This was, however, quickly followed by a spectacular rebound of fertility upon the liberation of the country in 1979, which led to a remarkable baby boom in the early eighties.

The world population, which progressively increased since the origin of history, is now entering an unprecedented transition leading to progressive shrinkage, with some countries leading the trend in Asia. Cambodia is no exception, even if TFR is for the time being still above replacement level. Today, Cambodia has a fertility rate that is, as in the 60s, at par with its neighbor, Vietnam. But in both countries, TFR stands at a much lower level, just at replacement rate. Cambodia is not immune to the fertility decline that affects the whole world and Asia, in particular. The government should be aware of the problem and cognizant of its consequences for the country’s future. Authorities must anticipate the further fertility decline that lies ahead and enact without delay measures helping families to cope with the costs of family building as well as facilitating access to fertility treatments.

Reproductive Medicine Societies such as notably, ASPIRE and its European—European Society of Human Reproductive Medicine (ESHRE)—and American counterparts—American Society of Reproductive Medicine (ASRM)—should help voicing the urgent concern about declining fertility and its consequences. ASPIRE, ESHRE, and ASRM should mount a joint effort for lobbying governments and other actors—advocacy groups and others—in order to implement measures to mitigate the consequences of fertility decline. This notably includes enlarging access to fertility treatment— enacting reimbursement—and making fertility preservation more easily available (Hagege et al., 2024a,b).

PERSONAL STATEMENT

The opinions expressed in this manuscript are solely those of the authors.

ORCID

Dominique de Ziegler  https://orcid.org/0000-0002-2513-8220