LIFESTYLE ISSUES AND ENVIRONMENTAL TOXINS
Couples experiencing recurrent pregnancy losses are often concerned those toxins within the environment may have contributed to their reproductive difficulty. It is important that health care providers, counseling patients about exposures to substances in the environment, have current and accurate information in order to respond to these concerns.
Cigarette smoking reduces fertility and increases the rate of spontaneous miscarriage. The data evaluating smoking and miscarriage are extensive and involve approximately 100,000 subjects. The studies suggest a clinically significant detrimental effect of cigarette smoking that is dose dependent, with a relative risk for miscarriage among moderate smokers (10 cigarettes a day). Patients should be aggressively counseled to stop cigarette smoking prior to attempting pregnancy.
Alcohol consumption associated with a risk of spontaneous miscarriage. The minimum threshold dose for significantly increasing the risk of first trimester miscarriage appears to be 2 or more alcoholic drinks per week. When personal habits, cigarette smoking and alcohol are utilized in the same individual, the risk of pregnancy loss may increase 4-fold. Couples should be counseled concerning these habits and strongly encouraged to discontinue these prior to attempting subsequent conception. One alcoholic drink equals one 12 oz beer, one 5 ounce glass of wine, or one ounce of alcohol.
Obesity, defined as a body mass index over 30, has been associated with an increased risk of miscarriage. Obesity (BMI >30 kg/m2) has been shown to be an independent risk factor for first trimester miscarriage]. The association is strongest in women with BMI > 40. The etiology of this phenomenon is unclear. However, many studies have linked obesity to a generalized increase in systemic inflammatory responses.
Several studies have shown that caffeine in excess of 400 mg/day (2 cups of coffee per day) is associated with a modest increase in spontaneous miscarriage, but it is not clear if this relationship is causal.
The studies of atomic bomb survivors in Japan showed that in utero exposure to high-dose radiation increased the risk of spontaneous miscarriages, premature deliveries, and stillbirths. Diagnostic X-rays in the first trimester delivering less than 5 rads are not teratogenic]. Large doses (360 – 500 rads) used in therapeutic radiation, however, induce miscarriage in offspring exposed in utero in the majority of cases. Adverse effects of chronic low-dose radiation on reproduction have not been identified in humans].