In 2010, 7.6 million children under the age of five died worldwide and yet the causes of only 2.7% (0.205 million) of these deaths were medically certified. A thorough understanding of the causes of child mortality is necessary to guide research efforts aimed at tackling this important global health problem. Prospective birth cohort studies present an opportunity to examine the relationships between early-life exposures and multiple health and non-health related outcomes including death, illness, and socioeconomic factors. In this study, the investigators will provide insight into the underlying causes of child mortality by collecting data on early-life exposures and health and non-health related outcomes in the first year of life.

In 2010, 7.6 million children under the age of five died worldwide, mainly from preventable and treatable conditions (Liu et al., 2012). Notably, the burden of under-five mortality varies dramatically by country. The majority of child deaths are seen in Africa (3.6 million) and southeast Asia (2.1 million deaths), compared to 0.16 million and 0.28 million under-five deaths in Europe and the Americas, respectively (Liu et al., 2012). In Kenya, over 120,000 under-5 deaths were estimated in 2010 and approximately 35% of these deaths occurred in the neonatal period.

A thorough understanding of the etiology of child mortality is necessary to guide research efforts aimed at tackling this important global health problem. Importantly, in 2010, the causes of only 2.7% (0.205 million) of all deaths in children under the age of five were medically certified (Liu et al., 2012), highlighting the need to gather data on the causes of mortality.

Prospective longitudinal birth cohort studies present an opportunity to examine temporal relationships between early-life exposures (i.e. prenatal, pregnancy, and early postnatal exposures) and multiple health and non-health related outcomes including mortality, morbidity, and socioeconomic circumstances. It is well documented that exposures that occur early in life, including genetic, environmental, socioeconomic, and lifestyle factors, may have long-lasting effects on growth, development, and health outcomes throughout an individual's entire life course (Lynch & Smith, 2005). Thus, data on exposures during pregnancy and early childhood are valuable and may provide clues to the etiology of long-term outcomes.

Additional value can be gained through cross-cohort collaborations and comparisons (Larsen et al., 2013)(Paternoster et al., 2012)(Brion et al., 2011). Notably, by pooling data from multiple cohort studies, causal inferences can be made with greater confidence. For example, if a similar relationship is observed across multiple populations, each with their own distinct set of confounding variables, it is less likely that the observed association is being driven by confounders. Similarly, cross-cohort comparisons enable researchers to investigate patterns associated with health, social, and economic outcomes in distinct regions of the world. These types of analyses may provide valuable insight into the underlying causes of global health inequalities.

The objective of this study is to implement a longitudinal prospective birth cohort study in Kenya to obtain extensive information on early-life exposures and health and non-health related outcomes in the first year of life.

Inclusion Criteria:

i. All pregnant women and their home- or facility-born live newborns that consent to participate in the control arm of the study "An integrated toolkit to save newborn lives and brains in Kenya" (NCT02208960) will be eligible for this study. The maternal inclusion criteria will be:

1. All pregnant women in parts of study clusters covered by CHW program and their home- or facility-born live newborns.
2. Mothers intending to maintain residence in study area for first 12 months of newborn's life.

Exclusion Criteria:

i. Did not consent to participate in the control arm of "An integrated toolkit to save newborn lives and brains in Kenya" (NCT02208960).

ii. Failure to provide consent to enroll in this study.

All pregnant women (and their unborn newborns) who consent to participate in the control arm of the previously approved trial "An integrated toolkit to save newborn lives and brains in Kenya" (NCT02208960) will be eligible for enrollment in this study. At the time of consent, participants will be informed that they are free to consent to the neonatal kit trial without consenting to the birth cohort study.