Any woman who becomes pregnant brings with her a variety of genetic and acquired factors that have the potential to impact the course of pregnancy. Genetic predisposition plays a significant role in obvious ways (e.g., sickle cell trait, Tay–Sachs, cystic fibrosis) or in more subtle manners (e.g., polymorphic tumor necrosis factor-α which may contribute to a predisposition to preterm labor). Anatomic factors may also contribute (e.g., congenital cervical incompetence, anomalous uterus). Physiological considerations such as the function of the hypothalamic–pituitary–ovarian axis (e.g., oligomenorrhea, anovulatory cycles) also play a role in becoming pregnant and in maintaining pregnancy.

Pregnancy is one potential medical event in the life of a woman, but it is by no means the only one. In addition to the genetic, anatomic, and physiological factors, many women will also acquire medical conditions that may impact the course or outcome of pregnancy. Such conditions as diabetes mellitus, hypertension, and cardiac, renal, or thyroid disease all impact the course of subsequent pregnancies. Not only do underlying disease conditions have the potential to directly impact obstetrical outcomes, many of the medications and treatments for these conditions may also have obstetrical implications. Surgical interventions involving cervical, pelvic, or intra-abdominal manipulation may also have consequences in pregnancy.

A variety of behavioral issues have direct bearing on pregnancy. Nutritional status is critical and has been the focus of recent recommended interventions such as folate supplementation prior to pregnancy. Much work has focused on the detrimental effects that tobacco, alcohol, and other drug use may have during pregnancy. Intrauterine growth rates, congenital anomalies, infant addiction, and preterm complications—among others—have all been shown to be impacted by the use of these substances. Patient exercise, fitness, and activity levels may also contribute to pregnancy outcomes.

Although potentially less obvious, the environment in which the woman lives may contribute significantly to obstetrical outcomes. For example, lower socioeconomic status is associated with higher complication rates and/or less good outcomes in a variety of obstetrical conditions such as preterm labor, pregnancy-induced hypertension, and others. Family and partner support for the pregnancy may impact the degree to which women access care during pregnancy.

All of these factors are present prior to conception providing the biopsychosocial environment in which the pregnancy will occur. Because these factors are all present—potentially identifiable and potentially modifiable—prior to conception, it is helpful to consider pregnancy and prenatal care as beginning prior to conception as well.