Pesticide exposure during pregnancy; how risky is it?
According to the Environmental Protection Agency, a pesticide is any substance that is used to destroy, repel, control, or prevent plants and animals considered to be “pests.” In Nepal, the most common types of pesticides are fungicides, organophosphates, and pyrethroids.
Use of pesticides in agriculture farming has become highly prevalent in Nepal. It has been increasing by about 10-20% each year. More than 80% of those pesticides imported into the country are used in vegetable farming, which adversely affects the health of consumers. A study conducted by the Nepal Public Health Foundation in the Chitwan District in 2017 revealed that more than 90 percent of farmers use pesticides on their farms; more than half of them have been using chemical pesticides for more than a decade.
Pesticides can enter the body through absorption (skin), inhalation (lungs) and ingestion (mouth). The health effects of pesticides may be acute or delayed to exposed populations and it depends on the duration of exposure. Evidence has shown that exposure to pesticides may lead to acute health problems like dizziness, skin irritation and allergy, body swelling, lethargy, etc while prolonged exposure may lead to leukemia, skin cancer, neurological problems, birth defects, fetal death, and so on.
The high risk groups for pesticide exposure include farmers, pesticide spray workers, pregnant women, pesticide retailers, and all consumers. Among these, pregnant women are one of the most vulnerable groups. Pregnant women who have been exposed to pesticides are at a greater risk of adverse health effects.
Pesticides adversely affect reproductive system, and repeated exposure can sometimes kill or damage cells, resulting in infertility. Some other effects of pesticide use during pregnancy include increased sexual dysfunction, and increased levels of hypertension. Pesticides and their adverse health effects on pregnant women is an emerging issue, and one we must pay attention to, since it affects the health of the both mother and child.
Let us also look at a few research studies that have been conducted on the impact of pesticides on pregnancy outcomes. A recent study from 2017 compared high levels of pesticide exposure to adverse birth outcomes in an agricultural population in California. The study compared 500,000 birth observations, to see if residential agricultural pesticide exposure during gestation, by trimester, and by toxicity influenced birth weight, gestational length, or birth abnormalities.
This study found that mothers exposed to extreme levels of pesticides (around 4200 kg of pesticides during gestation) experienced a 5 to 9 percent increase in the probability of adverse birth outcomes, with an approximately 13-gram decrease in birth weight. The study also found negative effects of pesticide exposure for all birth outcomes, including low birth weight, gestational length, preterm birth, and birth abnormalities.
Again, these outcomes were seen in mothers with high levels of pesticide exposure. Another study completed in Egypt in 2016 followed approximately 140 pregnant women through delivery. 40 women were exposed to pesticides, and 100 were not. Outcomes were assessed by gestational age at delivery, birth weight, head circumference, and body length of the newborn. This study confirmed the association of organophosphates with reduced gestational age, low birth weight, and small head circumference.
According to various research studies, adverse birth outcomes are inevitably linked to pesticide use or exposure during pregnancy. Such studies are lacking in Nepal. It would be a milestone if the magnitude of such problems could be assessed in the context of Nepal, because a significant proportion of Nepalese women are involved in agriculture farming. These studies would be important steps to shape policies regarding the safe and rational use of pesticides, and to adopt adequate safety measures to protect the health of pregnant women and their children.
- (Authors are public health professionals working with Nepal Public Health Foundation having an objective to ensure the health of farmers, pregnant women and consumers through the reduction of use and harm of chemical pesticides in agriculture farming).