Reproductive Health

Dr. Shanna Swan is an American environmental and reproductive epidemiologist. She is a Professor of Environmental Medicine and Public Health at the Icahn School of Medicine at Mount Sinai, where she has taught since April 2011. She is known for her research on environmental contributions to sperm count and the male infertility crisis.

This synopsis from PBS is a good introduction to Dr. Swan and her work:

Dr. Swan’s work has been featured in a number of high-profile publications, including The New York Times, The Washington Post, and The Guardian. She has also appeared on a number of television shows, including 60 Minutes and The Today Show.

Dr. Swan is a leading expert on the environmental impact on human health. Her work has helped to raise awareness of the risks of exposure to environmental chemicals and has informed public policy decisions. She is a passionate advocate for protecting the health of future generations.

Dr. Swan is also the author of the book “Count Down: How Our Modern World Is Threatening Sperm Counts, Altering Male and Female Reproductive Development, and Imperiling the Future of the Human Race”. The book was published in 2021 and has been praised for its clear and concise explanation of the science behind the male infertility crisis.

Dr. Swan is a Fellow of the American Association for the Advancement of Science and the Society for the Study of Reproduction. She is also a member of the National Academy of Medicine.In 2021, she was awarded the Rachel Carson Prize for her work on the environmental impact on human health.

Dr. Jodi Flaws leads a reproductive toxicology laboratory where her and her team invistigate:

• Chemicals that affect the development of the ovary
• Chemicals that affect the function of the adult ovary
• Effects of environmental chemicals on development and function of the female reproductive system
• Chemical exposures that are associated with adverse menopausal outcomes in women

Learn More: Flaws Lab

Presented by Beyond Plastics in 2021.

Webinar Summary

Plastics contain concerning chemicals that can interfere with hormones and reproduction, so minimizing exposure through consumer choices and advocacy for improved regulations is important for protecting health.

• Plastics contain chemicals like phthalates and BPA that are endocrine disruptors and can interfere with hormones like testosterone and estrogen. This can negatively impact fertility and reproduction.
• Exposure to these chemicals early in life, especially prenatally, can have lasting impacts on reproductive development and health later in life.
• Studies show sperm counts have declined significantly in Western countries over the past few decades, and exposure to endocrine disrupting chemicals is a likely contributor.
• Microplastics are now being found in human placentas and may impact fetal development and health. More research is needed on potential effects.
• Reducing exposure to plastics, especially avoiding plastic food and beverage containers, is recommended to protect reproductive health. Reading ingredient lists and choosing products without phthalates and other endocrine disruptors is also advised.
• Better regulation of chemicals in products is needed, as currently many are assumed safe until proven otherwise. More comprehensive testing at low doses reflecting real-world exposures is necessary.

Watch Full Webinar: YouTube

Presented by Plastic Pollution Coalition in 2021

Summary of Webinar

Evidence suggests plastics and associated EDCs are likely key contributors to observed declines in human fertility and reproductive health. Reducing exposure may help, but broader action is urgently needed.

• Sperm counts have dropped significantly (around 40%) between 1973 and 2011, and are projected to reach zero by 2045 if current trends continue. This signals a serious threat to male fertility.
• Reproductive health has been declining in both men and women over at least the past 40 years. This includes decreases in sperm count, testosterone, and increases in genital birth defects, infertility, menstrual problems, endometriosis, premature egg depletion, etc.
• The decline seems to be driven largely by environmental factors, especially exposure to endocrine disrupting chemicals (EDCs) like phthalates and bisphenols that are commonly found in plastics.
• EDCs can interfere with hormones like testosterone that are critical for proper reproductive development and function. Animal studies clearly show reproductive effects from EDCs, and human studies also demonstrate associations.
• Plastics and EDC chemicals are now ubiquitous globally, contaminating even remote areas through processes like evaporation/wind dispersal, bioaccumulation, etc. Constant low-level exposure is a concern.
• EDCs act at extremely low doses, in the same range as natural hormones. Thus traditional toxicology testing often misses their impacts.
• Reducing exposure to plastics/EDCs can help lower personal EDC levels, but policy change is ultimately needed to address this issue comprehensively and equitably.

Watch Full Webinar: YouTube

Dr. Thalia Segal is a fertility specialist at UCSF. She diagnoses and treats causes of infertility and reproductive disorders.

Interview Summary

Some of the key points Dr. Thalia Segal makes are:

• Plastics like BPA and phthalates are everywhere – in plastic bottles, toys, food containers, etc. These chemicals can disrupt hormones and impact health.
• BPA can leach out from plastics, especially when heated like in microwaves or dishwashers. Phthalates are used in fragrances and many personal care products.
• These chemicals have been associated with fertility issues, problems getting pregnant, lower IVF success rates, and higher risk of fibroids.
• During critical periods like pregnancy and childhood, reducing exposure to these chemicals is especially important.
• Simple changes can help – choose glass, stainless steel or silicone over plastic for food containers. Avoid canned foods lined with BPA. Pick fragrance-free products.
• Eating fresh, organic foods when possible can reduce pesticide exposures that also act as hormone disruptors.
• Check out the Environmental Working Group’s website and app to look up products and their safety profiles.
• While these chemicals are widespread, reducing our exposure, especially during key life periods, can make a meaningful difference. Even short term reductions can lower levels.

Watch Full Interview: YouTube

Dr. Shanna Swan was interviewed by Joe Rogan in 2021.

Interview Summary

Swan’s research indicates chemicals like phthalates used in plastics can negatively impact genital development, fertility, and reproductive health when exposure occurs in the womb. The proliferating use of plastics exposes more people to these concerning effects. Key points from interview:

• Around 2000, animal studies found that rats exposed to phthalates (chemicals used to make plastics flexible) in utero had altered genital development and smaller penises. This is called the “phthalate syndrome”.
• Swan wanted to see if phthalates had similar effects in humans. She measured phthalates in pregnant women’s urine and examined their baby boys’ genitals after birth. She found higher phthalate levels were associated with smaller penises and shorter anogenital distance (the space between the anus and genitals).
• She also found young men with shorter anogenital distances had lower sperm counts. This suggests phthalate exposure in the womb may affect reproductive development in a way that impairs fertility later in life.
• Phthalates and other plastic chemicals can disrupt hormones like testosterone that are critical for genital development and reproduction.
• The use of plastics and plastic chemicals grew exponentially after 1950, so human exposure has increased dramatically in recent decades. This tracks with declines in sperm counts over time.

Watch Full Interview: YouTube

Interview by Plastic Pollution Coalltion in 2022

Interview Summary

Here are some of the key points Dr. Shanna Swan made about plastics, phthalates and reproductive health in this interview:

• Sperm counts in Western countries have declined dramatically, dropping 52% between 1973 and 2011. This decline points to effects of environmental chemicals like phthalates on male reproductive health.
• Phthalates are chemicals added to plastics to make them soft and flexible. They can leach out of plastics and enter our bodies through food, drink, dust, etc.
• Phthalates disrupt hormones like testosterone and can lead to the “phthalate syndrome” in baby boys exposed in utero, which includes smaller genital size and later lower sperm counts and fertility issues.
• Higher phthalate exposure for pregnant women is linked to genital changes, lower sperm counts, changes in brain development and behavior in their male children.
• Phthalates are also added to products like cosmetics, perfumes, cleaning products to help absorption and scent retention. Fragrance-free products have lower phthalate levels.
• Current chemical testing paradigms are outdated. To protect human health, we need to test effects of low doses, mixtures, and real-world exposures to phthalates and other hormone disrupting chemicals.
• To reduce exposure, she suggests avoiding plastics in cooking and storage, choosing fragrance-free products, and purchasing glass, ceramic and metal alternatives when possible.

Watch Full Interview: YouTube

Study Summary

“Conclusion: Based on reports that BPA impacts female reproduction and has the potential to affect male reproductive systems in humans and animals, we conclude that BPA is a reproductive toxicant.”

This review of published research studies systematically goes through the best research on BPA and fertility (up through 2014).

It breaks down what research has revealed on various aspects of reproduction such as:

• Ovarian Follicle Formation
• Embryo Development
• Pregnancy Outcomes
• Birth Weight
• And much more…

Key Takeaway: it is highly likely that BPA exposure has a negative impact on our ability to successfully reproduce.

Citation: Peretz J, Vrooman L, Ricke WA, Hunt PA, Ehrlich S, Hauser R, Padmanabhan V, Taylor HS, Swan SH, VandeVoort CA, Flaws JA. Bisphenol a and reproductive health: update of experimental and human evidence, 2007-2013. Environ Health Perspect. 2014 Aug;122(8):775-86. doi: 10.1289/ehp.1307728. Epub 2014 Jun 4. PMID: 24896072; PMCID: PMC4123031.

Read Full Paper: nih.gov

Study Summary

“…we conclude that there is sufficient evidence to suggest that phthalates are reproductive toxicants. However, we note that the concentrations needed to induce adverse health effects are high compared to the concentrations measured in contemporary human biomonitoring studies.“

Citation: Kay VR, Chambers C, Foster WG. Reproductive and developmental effects of phthalate diesters in females. Crit Rev Toxicol. 2013 Mar;43(3):200-19. doi: 10.3109/10408444.2013.766149. Epub 2013 Feb 13. PMID: 23405971; PMCID: PMC3604737

Read Full Paper: nih.gov

Study Summary

Here are the key points about Dr. Nathan Cohen’s study on PFAS chemicals and female fertility:

• The study was conducted by Dr. Nathan Cohen at the Icahn School of Medicine at Mount Sinai in New York.
• It included over 1,000 women of childbearing age in Singapore who were trying to conceive.
• Women with PFAS levels one quarter higher than average had a 40% lower chance of getting pregnant within a year.
• These women also had a 34% lower chance of having a live birth within 12 months.
• The negative effect of PFAS on fertility was greater when looked at as a mixture rather than individually.
• The study did not examine how PFAS affects fertility but prior research suggests effects on hormones, egg production and function.
• The findings link higher PFAS exposure to reduced female fertility, consistent with previous smaller studies.
• The researchers recommend women trying to conceive should avoid PFAS exposure and take precautions.

Citation: Nathan J. Cohen, Meizhen Yao, Vishal Midya, Sandra India-Aldana, Tomer Mouzica, Syam S. Andra, Srinivasan Narasimhan, Anil K. Meher, Manish Arora, Jerry Kok Yen Chan, Shiao-Yng Chan, See Ling Loy, Lidia Minguez-Alarcon, Youssef Oulhote, Jonathan Huang, Damaskini Valvi,
Exposure to perfluoroalkyl substances and women’s fertility outcomes in a Singaporean population-based preconception cohort, Science of The Total Environment, Volume 873, 2023

Read Full Paper: ScienceDirect.com

We are unable to access the full paper. Key facts from this research were referenced here: EDC Guide 2020 (pg. 65)

Citation: Tabacova S LR, Balabaeva L. Maternal exposure to phthalates and complications of pregnancy.
Epidemiology. 1999(10).

Study Summary

Microplastics may significantly contribute to declining male fertility, but more direct human evidence is still needed. Reducing plastic pollution and human exposure is prudent given the potential risks.

Key points regarding plastics and male fertility:

• Plastic pollution has become a major global issue, with plastics breaking down into microplastics that can enter the food chain and human body.
• Male semen quality has declined significantly over the past 80 years, which coincides with the rise of plastics. Microplastics may be contributing to male infertility.
• Animal studies show microplastics can reduce sperm quality, increase sperm DNA damage, and cause testicular damage. The minimum dose causing effects in rodents corresponds to about 16 μg/kg/day for humans.
• Some countries like Japan and South Korea have human exposure levels close to this minimum dose. So current microplastic exposure may already be impacting male fertility in some regions.
• More research is needed on microplastic exposure levels in humans, effects on semen parameters, deposition/clearance mechanisms, and intake routes. Monitoring of microplastics in air, water and food is recommended.

Citation: Zhang C, Chen J, Ma S, Sun Z, Wang Z. Microplastics May Be a Significant Cause of Male Infertility. Am J Mens Health. 2022 May-Jun;16(3):15579883221096549. doi: 10.1177/15579883221096549. PMID: 35608037; PMCID: PMC9134445.

Read Full Paper: nih.gov

Study Summary

Phenols are used in plastics to create a material that is strong, durable, and resistant to heat and chemicals (eg. Bisphenol A – BPA).

Idiopathic male infertility is a condition in which a man is unable to conceive a child despite having normal semen parameters. This means that the man’s sperm count, motility, and morphology are all within the normal range.

Key points from this study:

• There was a case-control study with 877 idiopathic infertile men and 713 fertile controls to examine the association between exposure to various phenols and idiopathic male infertility.
• Urinary levels of bisphenol A, benzophenone-3, pentachlorophenol, triclosan, 4-tert-octylphenol (4-t-OP), 4-n-octylphenol (4-n-OP) and 4-n-nonylphenol (4-n-NP) were measured.
• After multivariate adjustment, exposure to 4-t-OP, 4-n-OP and 4-n-NP was associated with increased risk of idiopathic male infertility.
• Exposure to 4-t-OP and 4-n-NP was also associated with increased risk of idiopathic male infertility with abnormal semen parameters.
• Significant associations were observed between total alkylphenol exposure and idiopathic male infertility.
• No relationships were found between exposure to other phenols (bisphenol A, benzophenone-3, pentachlorophenol, triclosan) and idiopathic male infertility.
• The study provides the first evidence that exposure to alkylphenols may be associated with increased risk of idiopathic male infertility in humans.

Citation:

Chen M, Tang R, Fu G, Xu B, Zhu P, Qiao S, Chen X, Xu B, Qin Y, Lu C. Association of exposure to
phenols and idiopathic male infertility. Journal of hazardous materials. 2013;250:115-121.

Read Full Paper: sciencedirect.com

Study Summary

The hazardous chemicals associated with microplastics have properties that could plausibly impact human fertility, but direct evidence in humans is still an open research question requiring more study.

Key points regarding plastics and fertility:

• Bisphenol A (BPA) and phthalates used as plastic additives are known endocrine disruptors that can impact human reproduction.
• Dibutyl phthalate (DBP) is classified as toxic for reproduction and prenatal/postnatal development in animals. It may affect fertility.
• Lead which can be present in microplastics is associated with infertility in both men and women.
• In vitro studies show polystyrene nanoparticles can cross the placental barrier, indicating potential for impacts on the fetus.
• Flame retardants like PBDEs have been shown to be toxic for reproduction in animal studies. Their transfer from microplastics is possible.
• In general, the chemicals associated with microplastics have modes of action that include disrupting hormones and the endocrine system, which could impair fertility and reproductive function.

Citation: Campanale C, Massarelli C, Savino I, Locaputo V, Uricchio VF. A detailed review study on potential effects of microplastics and additives of concern on human health. Int J Environ Res Public Health. 2020;17(4):1212. Published 2020 Feb 13. doi:10.3390/ijerph17041212

Read Full Paper: nih.gov

Study Summary

The study found exposure to perfluorinated chemicals was associated with later timing of puberty in both boys and girls. The public health implications of relatively modest delays in pubertal development require further investigation.

Key points from this research article on perfluorinated chemicals and puberty:

• The study examined associations between perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) exposure and indicators of pubertal development in children aged 8-18 years. It was conducted in communities with drinking water contaminated by PFOA.
• Sex steroid hormone levels (testosterone and estradiol) and age at menarche were used as markers of pubertal status.
• Higher PFOS levels were associated with later puberty in both boys and girls, based on the different indicators. Higher PFOA levels were associated with later puberty in girls but not boys.
• For PFOS, there were delays of 190 days in boys and 138 days in girls between highest and lowest exposure groups. For PFOA, there was a 130 day delay in girls.
• The findings suggest PFOA and PFOS exposure may lead to delays in pubertal maturation of around 3-6 months in this population.
• Strengths include the large sample size and high participation rate. Limitations include the cross-sectional design and lack of pre-pubertal PFC measurements.

Citation: Lopez-Espinosa MJ, Fletcher T, Armstrong B, et al. Association of Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS) with age of puberty among children living near a chemical plant. Environmental Science & Technology. 2011 Oct;45(19):8160-8166. DOI: 10.1021/es1038694. PMID: 21534542.

Read Full Paper: Environmental Science & Technology