How Healthy Are Our Babies, Really?

Author: Cindy Su '26

Editor: Wonjin Ko '25

Introduction

Endocrine disrupting chemicals (EDCs) are substances that interfere with the functions of the endocrine system [2]. Investigating EDCs has become increasingly important because these substances permeate nearly everywhere in our daily lives as modern humans [2]. Although EDCs affect both women and men, this article will focus on examples and the implications of EDCs during pregnancy because this stage of life is particularly sensitive to environmental factors [2]. This is due to the fact that fetuses are immature and have a high cell differentiation rate, leading small changes to grow into large changes [1, 2]. 

Maternal exposure to EDCs during pregnancy may adversely affect fetal development [1]. This could appear unknowingly as purchasing certain packaged foods, using cosmetics, wearing certain textiles in our daily lives, for example [2]. When the many hormonally mediated processes during fetal development are interrupted by EDC exposure, life-long metabolic and neurological issues may occur in the child [1]. Other chemical properties are also attributors to the harmful effects of these chemicals [2]. The general mechanisms as to why this occurs on a biological level are the alteration of the “synthesis, secretion, binding, transportation, metabolisms, and/or elimination of key hormones” [2]. EDCs can also cross through the placenta, an important organ that maintains fetal homeostasis by exchanging nutrients, gasses, and signaling molecules in addition to being a protective barrier [2]. EDCs also have the ability to alter placental cells, and thus alter the protection for the fetus [2]. 

Let’s dive deeper into some major examples of EDCs, and how they are harmful.

Bisphenols

Have you drunk out of a plastic water bottle? Or have eaten packaged foods? Bisphenols are found in bottles, food packaging, and metal coatings found in cans or bottle tops [2]. Thus, diet is the primary form of bisphenol exposure [2]. 

Bisphenols, specifically bisphenol A (BPA), have been shown to limit blood supply to both the placenta and fetus, lead to preeclampsia, and premature birth or pregnancy loss [2]. They may also interfere with human chorionic gonadotropin (hCG) secretion, which maintains progesterone production and cell growth in the placenta and uterus [2]. When such protective organs are altered, fetal development may be at risk for harm. BPAs, even at a low dose, may also activate the ERK signaling pathway [2]. The ERK signaling pathway affects gene expression, which may lead to a depletion in estradiol and progesterone synthesis, and low levels of these hormones may lead to placental insufficiency and subsequently, pregnancy failure [2, 4]. 

The mechanism behind BPAs effects on the placenta and fetus is the modification of DNA methylation and subsequently, gene expression [2]. Thus, fetal exposure to BPAs will alter the predicted DNA methylation of newborns and may lead to disease susceptibility [2]. Because of the high amounts of DNA synthesis and gene expression establishment, BPA-mediated epigenetic disruption can be detrimental to fetal development [2]. As a result, fetal exposure to BPA leads to epigenetic changes [2]. 

Phthalates 

Phthalates are plasticizers that increase the flexibility and durability of plastics and are found in food packaging, personal care products, toys, and textiles, to name a few [2]. Phthalates are extremely widespread, and are found in nearly 100% of tested subjects [2]. This is especially worrying, because phthalates can damage DNA [2]. They induce oxidative stress, which can modify mRNA and microRNA expression and cause oxidative DNA damage, which leads to epigenetic changes when methylation proteins cannot chemically bind to the damaged DNA [2]. With the fact that fetuses are establishing gene expression mechanisms during their development, this is notably harmful.

Pesticides 

So much of our agriculture and produce are grown with pesticides. As a result, most of us have consumed these substances frequently!

One type of pesticide is organochlorine pesticides (OCPs) can alter proteins that metabolize toxins, including OCP itself [2]. Metabolizing OCP also releases reactive oxygen species, similar to phthalates, which leads to oxidative stress, DNA damage, and impaired mitochondrial functioning [2]. OCPs also alter the function of placental cells, hormone secretion, and nutrient transport, ultimately affecting the fetus [2]. The presence of OCPs are correlated with miscarriage, premature birth, and low birth weight [2]. 

Perfluorinated compounds (PFCs)

You’ve probably used something with waterproof or non-stick properties at least once in your life. And there’s a good chance it contained PFCs. 

These substances are commonly found in cookware, food packaging, and food processing due to its non-stick properties [3]. Exposure to PFCs during pregnancy has been associated with lower placental and fetal weight [2]. PFCs may alter steroid hormone signaling by reducing aromatase production, estradiol liberation, and progesterone generation. These mechanisms may lead to the effects certain PFCs have on newborns and fetuses. For example, PFOS, a type of PFC, leads to lower cell viability and apoptosis [2]. PFOA may also lead to poor fetal growth and negatively affect birth weight [2]. 

Parabens

Certain chemicals can prevent our personal care products from going bad. However, these substances may be harmful. 

Parabens are used as preservatives in personal care products [2]. Placental cells may undergo apoptosis when exposed to parabens [2]. Parabens may also be associated with altered testosterone levels and in turn raise the susceptibility for impaired fetal development [2]. Although parabens are useful in some ways, they might also have an effect on healthy pregnancies. 

What can you do for your own health?

By being aware of the presence of EDCs, you have more control over your health! Whenever you purchase personal care products, for example, you can research their ingredients to see if there are any harmful chemicals. Certain apps, such as EWG Healthy Living, have been made for users to quickly find any substances that are harmful to their health. By fully understanding what you’re purchasing, you can avoid being exposed to unhealthy substances. 

References

1. Braun, Joseph M. “Early-life exposure to edcs: Role in childhood obesity and Neurodevelopment.” Nature Reviews Endocrinology, vol. 13, no. 3, 2016, pp. 161–173, https://doi.org/10.1038/nrendo.2016.186. 

2. Puche-Juarez, M.; Toledano, J.M.; Moreno-Fernandez, J.; Gálvez-Ontiveros, Y.; Rivas, A.; Diaz-Castro, J.; Ochoa, J.J. The Role of Endocrine Disrupting Chemicals in Gestation and Pregnancy Outcomes. Nutrients 2023, 15, 4657. https://doi.org/10.3390/nu15214657

3. Center for Food Safety and Applied Nutrition. “Authorized Uses of Pfas in Food Contact Applications.” U.S. Food and Drug Administration, FDA, www.fda.gov/food/process-contaminants-food/authorized-uses-pfas-food-contact-applications#:~:text=Since%20the%201960s%2C%20the%20FDA,%2C%20and%20water%2Dresistant%20properties. Accessed 26 Nov. 2023. 

4. Lu, N., & Malemud, C. J. (2019). Extracellular Signal-Regulated Kinase: A Regulator of Cell Growth, Inflammation, Chondrocyte and Bone Cell Receptor-Mediated Gene Expression. International journal of molecular sciences, 20(15), 3792. https://doi.org/10.3390/ijms20153792