Hormonal contraception and hemoglobin levels in urban Malawi: a longitudinal analysis

Hormones can be classified into three main types based on their chemical structures: steroids, peptides, and amines. Their actions are mediated by the specific receptors they bind to on target cells.

Hormones are classified into four main groups: steroids, eicosanoids, amino acid-based derivatives, and peptide hormones.
Steroids and eicosanoids fall under the category of lipid-soluble hormones. Steroids are derived from cholesterol and feature four interconnected carbon rings with variable side chains. Notable examples include estradiol from ovaries and testosterone from testes, exemplifying the critical roles of these lipid-soluble hormones in reproductive physiology. Eicosanoids, derived...

Hemoglobin is a globular protein made up of four subunits. Two of these subunits are alpha chains, and the other two are beta chains. Each subunit contains a molecule of heme, which has an iron atom and can bind to oxygen. When an oxygen molecule binds to one heme group, it changes the shape of hemoglobin, making it easier for the other heme groups to bind oxygen as well.
When all four heme groups are bound to oxygen, the resulting molecule is called oxyhemoglobin. As a result, arterial blood...

Sometimes we want to see how people change over time, as in studies of human development and lifespan. When we test the same group of individuals repeatedly over an extended period of time, we are conducting longitudinal research. Longitudinal research is a research design in which data-gathering is administered repeatedly over an extended period of time. For example, we may survey a group of individuals about their dietary habits at age 20, retest them a decade later at age 30, and then again...