Mortality under one year of age significantly decreased in all countries, and a convergence of the rates continued to be observed between the Baltic states and EU-28. This convergence occurred most rapidly in Estonia, where the rates of fetal mortality exceeded the data for EU-16 in 2000 for the first time ever, and the neonatal and infant mortality − in 2002. In subsequent years, the trend to divergent values was observed. In Lithuania, the convergence of mortality patterns occurred slightly later, the neonatal mortality rate exceeded the average of EU in 2010, while that of infant mortality did so in 2013. In Latvia, the mortality rate approached the average EU level at the end of the analyzed period, but did not yet exceed it. Time-lag analyses suggested that in the EU countries the increase in health expenditure and GDP was linked to a reduction fetal mortality with the strongest effects after a 4 and 5-year delay. Growth of health expenditure and GDP diminished neonatal mortality, especially in the same year.
The evidence changes related to decrease in mortality under one year of age in the Baltic states was reported by Rajaratnam et al, showing a decline in rates of neonatal and infant mortality in a cross-comparison across 21 regions of the world . There have also been published studies reporting inconsistent results or suggesting opposite trends in fetal mortality, being either decreasing or increasing [3, 15, 21]. In all the Baltic states, following the political and economic transformation, the Program of Perinatology was successfully started with the essential financial support of the Swiss government. Thereby, implemented organizational and structural changes in mother and neonatal care, including intensive care units and medical transport system, have significantly improved birth outcomes [14, 22]. There was a possibility that the preponderance regarding better birth outcomes in the Baltic states compared with the rest of EU resulted, at least partly, from a close cooperation with Scandinavian experts in the field and shared principles of good clinical practice in the perinatal and obstetric care . Nordic countries have prominent results on maternal and child health indicators, and low neonatal mortality rates [5, 8, 23, 24]. Noticeably, in Estonia the mortality rates under one year of age decreased most rapidly suggesting some country-specific factors. One of the possible explanations was the alleviation of income inequality and some beneficial effects of the maternal educational level [11, 25]. It is worth emphasizing that Estonia also significantly improved the health status of adult women as a result of health care activities and reduction of harmful lifestyle factors , which could have contributed to the improvement of birth outcomes. This dynamic evolution in Estonia after 2006 led to the divergent rates of mortality under one year of age with the EU, and Estonia achieving the level similar to the high-income countries. The divergence noted in Estonia provides some assumption that such a continuous improvement is also possible in Lithuania and Latvia.
The general health status among the population was worsening in the early 90's. After 1994, the situation turned into an improvement, but there was still a significant gap between the Baltic states and the EU in health status. In the Baltic countries mortality due to cardiovascular diseases, cancer, and suicides reached the highest rates in comparison with other EU countries [27, 28]. Significant improvements in perinatal and children health in the Baltic region give hope for faster improvement as well in the health of the whole population.
Our results showed that there is a concern about a slower velocity of the fetal mortality reduction compared to the neonatal and infant mortality in the Baltic countries and the EU. Around 80% cases of fetal deaths are antepartum stillbirths and that could be associated with a delay in the first antepartum visit or suboptimal care, and coincident poor socioeconomic status and harmful factors such as smoking [29, 30]. Our results showed that in the EU countries, capability to further the reduction of fetal and neonatal mortality through healthcare activities are still present. Moreover, an increase in GDP can bring benefits with improved fetal and neonatal health. A possible explanation of the results is that GDP growth contributes to an overall increase of socioeconomic resources, and to the increase of socio-economic status. With the larger GDP growth, countries are more likely to implement health care programs that improve fetal and neonatal health. These factors may be modifiable to a great measure, basically through the targeted prevention programs in the health care system and high quality hospital care services [26, 30–32]. In addition, the parallel investments in social policies and education for young women and families at high risk are important [4, 33–35]. It is important to mention that the fetal and neonatal health is an investment to the general health of the entire society and therefore may considerably influence and shape the health status of future generations.
Strengths and limitations
The strong side of this study was a focus on core indicators from Euro-Peristat used for the monitoring of trajectories mortality under one year of age in the Baltic states and the EU in the 25-year period (from 1990 to 2014). This study showed the areas of progress in fetal, neonatal and infant health in all countries, and also from year 2012, stagnation in the rate of infant mortality in Latvia and neonatal mortality in the EU. In addition, the strong side of the paper is comparability of mortality rate in Estonia, Latvia and Lithuania, where fetal mortality rates are lower or equal at 22 weeks of gestational age. However, in the investigated countries the recorded stillbirths exclude abortions of pregnancy which are recorded in another system [8, 9]. The above uniform criteria allows addressing the issue whether the decreasing trend of fetal mortality resulted from the decrease of stillbirth cases or because of the decreasing trend of terminating pregnancies. The study revealed that while excluding from our analysis 12 countries of the EU and using the data recording the criterion of over 22 weeks of gestation, the trend of fetal mortality rates decreased in EU-16 and those trends were similar to the Baltic states. In the EU-28, the trend remained stable  which caused us to conclude that exclusion of 12 countries gave the possibility for more exact estimation of similarities in fetal mortality trends, and converging or diverging trajectories between the Baltic countries and the EU.
This study showed important implications for policy; that improving the macroeconomic situation appears to diminish mortality under one year of age in the EU. It is important in terms of low fertility levels and may be a guide in the decision-making process regarding the distribution of resources aimed at intervention for child health . There is a need for government action to increase well-being and access to appropriate obstetric care. These factors can contribute not only for improvement in child health, but also for long-term effects throughout the lifecycle related to better adult health and increased productivity in the labor market.
A limitation of the study is the issue of data quality over time. The possibility of mismatches is still possible; even if mortality data and statistical information in the Baltic countries is used by the global health organizations and databases (for instance, the WHO) and are generally considered reliable and internationally comparable . Some limitations still could be linked with differences in definitional arrangements and registration as well as hospital policies regarding delivery and neonatal unit admission; particularly around the limits of viability in EU countries [24, 38]. Other limitations might appear because of the relationship between mortality and specific health expenditure categories. For instance, medical services in gynaecological and obstetric care or prevention programs have not been examined here because of lack of adequate data. Although health expenditure plays an important role in shaping the health of the population, their distribution into individual categories varies between countries . We have only partially assessed the relationship between health care and mortality. The effectiveness of health care, particularly in the context of improvement of perinatal and child health, appears as important as health expenditure per se. Noticeably, a relatively unfavourable health situation may also affect countries with high health expenditure, e.g. US. Thus, high expenditure may not necessarily be always projected into enhancement of public health status [5, 6]. On the other hand, it has been shown that the Baltic states achieved strikingly good health outcomes despite relatively low expenditures. These associations prove that some other (or unknown) factors connected with intervention programs and quality of health care services may play a role in moderating the effectiveness of the healthcare expenditure.
In this study we used lag-time analysis based on mortality and macroeconomic factors in EU countries within two decades, with regard to factors controlling population structure and inter-country differences. However, the aggregated data level in this analysis limited conclusions on potential causal relationship at an individual level. Independent variables used in the ecological study represent mortality and macroeconomic factors observed on the population level, and not the characteristics of individuals . An increase in health expenditure and GDP does not always translate into improvement of health outcomes, although the economic progress and stimulation was independently associated with mortality reduction. Furthermore, caution is advised while interpreting lag-time analysis because these results may be underestimated due to lacking or incomplete data on mortality, especially in newborns. Nevertheless, our study incorporated mortality reports from all EU countries based on high quality standard and reliable procedures of data collection.