Reproductive and Birth Outcomes and the Environment

Our understanding of risk factors for reproductive problems such as infertility, low birth weight, prematurity, fetal and infant death has increased over the past decades. There is still much we do not know. One big question is what role do environmental exposures play in reproductive and infant health problems? Although we have identified many risks related to several substances found in the environment, research in this area has been inconsistent. Some studies have found increased rates of birth problems while other studies have found no effect. Still, there are some environmental factors that may impact a woman's reproductive health:

• Exposure of nonsmoking pregnant women to environmental tobacco smoke (also known as secondhand smoke) may be a risk factor for preterm birth, low birth weight, and possibly fetal death (miscarriage).
• Exposure to some forms of air pollution (carbon monoxide, particulate matter, nitrogen dioxide) have been related to both low birth weight and preterm birth, even at low levels. A pregnant woman's exposure to lead may cause preterm birth, low birth weight, and spontaneous fetal death (miscarriage).
• Exposure to pesticides (herbicides, organochlorides, and organophosphates) has been associated with fetal death (miscarriage) and babies being born too small.

Occupational (work) exposure to pesticides may also be associated with intrauterine growth retardation and fetal death but more data is needed. Social conditions such as poverty, crime, poor health before pregnancy, and lack of access to medical care may cause birth problems. Yet, few studies have looked at how exposure or co-exposure to many environmental pollutants and social conditions together can affect birth outcomes.