Reproductive Health and Birth Outcomes Exposure and Risk
Risk factors other than the environment contribute to adverse reproductive and birth outcomes. Nutrition, genetics, and the mother’s health are important, as are early and high-quality prenatal care. The following behaviors and conditions can affect fetal development and lead to adverse birth outcomes:
- vitamin deficiencies such as inadequate folic acid intake,
- uncontrolled chronic diseases such as diabetes, and
- untreated infections, such as bacterial vaginosis and trichomoniasis.
There is data to suggest that caffeine intake increases the risk of spontaneous abortion in normal fetuses and intrauterine growth restriction. Published studies have reported mixed results. Because the amount of caffeine in food and drink is variable among studies, women are encouraged to limit their consumption of caffeine during pregnancy.
Cigarette smoking negatively affects pregnancy in different ways. In addition to miscarriage, smoking also increases the risk of abruptio placenta, placenta previa and bleeding during pregnancy. The risks appear to be dose dependent. Authors have also described an overall increase in congenital malformations among smokers. Exposure to secondhand smoke (passive smoking) has been linked to second trimester bleeding. Cigarette smoking during pregnancy is also associated with low birth weigh and stillbirth.
Alcohol consumption has been associated with an increase in first trimester miscarriage. There is no clear threshold of safe alcohol consumption in pregnancy. Drinking alcohol during pregnancy has been also linked with low birth weight.
Use of illicit drugs such as cocaine, methamphetamines, and others have been associated with higher miscarriage rates.
Many factors that cause low birth weights and preterm births are not well understood despite research efforts. The reasons for marked differences in the rate of adverse birth outcomes among different racial and ethnicity groups are largely unexplained.
Adverse birth outcomes do not result from a single, easily modifiable risk factor but most likely reflect multiple factors from many areas of both the father’s and mother’s lives.