Reproductive Health in Females and Males

Reproductive health refers to the condition of female 

and male reproductive systems during all life stages. 

These systems are made of reproductive organs, 

including the ovaries in females and the testicles in 

males. These organs produce and release hormones, 

as do other hormone-producing glands in the body 

such as the pituitary gland in the brain. 

Female disorders include: 

• Early or delayed puberty. 

• Menstrual problems.

• Infertility or reduced fertility.

• Problems during pregnancy.

• Polycystic ovary syndrome (ovaries produce 

more male hormones than normal).

• Uterine fibroids.

• Endometriosis. 

Male disorders include:

• Impotence or erectile dysfunction.

• Low sperm count. 

Research Findings From NIEHS 

NIEHS conducts and funds research to understand 

how our environment may affect both female and 

male reproductive health. 

• Chemical exposure may hinder reproductive 

assistance in women and men. Exposure to 

high levels of flame retardants1 and plasticizers2

may hinder in vitro fertilization (IVF), a medical 

procedure used to help women get pregnant. 

Women with higher levels of these chemicals in 

their urine had fewer ovary cells, and less 

successful pregnancies and live births.

Flame retardant chemicals, used in some electronic, 

fabric, and foam products, may enter your body 

by breathing dust or drinking water that is 

contaminated with them.

Men with higher levels of flame retardants3

 in their 

urine had less successful fertilization during IVF. 

In addition, urinary levels of phthalates4

 in males, 

but not females, were associated with lowerquality embryos.

• Air pollution and pregnancy hypertension.

Traffic-related air pollution increases a pregnant 

woman’s risk for blood pressure, or hypertensive, 

disorders.5

• Heavy lifting or shift work and decreased fertility. 

Two occupational factors for women — 

lifting heavy loads or working non-daytime 

schedules — are associated with fewer eggs, 

which could indicate decreased fertility.6

• Chemical exposure and fetal growth. Exposure 

during pregnancy to phthalates7 and phenols,8

chemicals commonly found in plastics, as well 

as arsenic, a naturally occurring chemical found 

in food, soil, and water, could lead to low birth 

weight,9 and the early onset of puberty.10

• Phthalates, parabens, and phenols associated 

with early puberty. The daughters of pregnant 

women whose bodies had high levels of these 

chemicals, which are common in personal care 

products, started puberty earlier than normal.11

• Soy formula and menstrual pain. Girls fed soy 

formula as infants are more likely to develop heavy 

menstrual bleeding,12 severe menstrual pain,13

endometriosis,14 and larger fibroids15 later in life. 

• Vitamin D and uterine fibroids. Women with 

adequate levels of vitamin D are less likely 

to develop uterine fibroids than those with 

inadequate levels.16

PO Box 12233 • Research Triangle Park, NC 27709

Phone: 919-541-3345 • www.niehs.nih.gov

February 2020

National Institutes of Health

U.S. Department of Health and Human Services

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National Institute of Environmental Health Sciences

Ongoing NIEHS Research

The Body Weight & Puberty Study, conducted 

at NIEHS, seeks to discover the effect of obesity on 

breast tissue development in girls. 

The Calorie Restriction, Environment, and Fitness: 

Reproductive Effects Evaluation (CaREFREE) 

study, conducted at NIEHS, analyzes how nutrition, 

fitness, and the environment affect women’s 

menstrual cycles.

The Demystifying a Girl's First Period study, 

conducted at NIEHS, will help us understand why 

puberty is experienced differently among girls.

The Environment and Reproductive 

Health (EARTH) study, conducted by grant 

recipients in Massachusetts, analyzes the effects 

of environmental contaminants on male and 

female fertility and pregnancy outcomes.

Pregnancy and Childhood Epigenetics (PACE), 

a consortium of researchers at NIEHS and 

around the world, studies how environmental 

exposures in early life affect pregnancy 

outcomes and child health. 

The Study of Environment, Lifestyle, and 

Fibroids (SELF), conducted at NIEHS, 

uses ultrasound screening to identify risk 

factors for uterine fibroid development in 

African American women.

 1 Carignan CC, et al. 2017. Urinary concentrations of organophosphate flame retardant metabolites and pregnancy outcomes among women undergoing in vitro 

fertilization. Environ Health Perspect 125(8):087018.]

 2 Hauser R, et al. 2015. Urinary phthalate metabolite concentrations and reproductive outcomes among women undergoing in vitro fertilization: results from the 

EARTH study. Environ Health Perspect 124(6):831–839.

 3 Carignan CC, et al. 2018. Paternal urinary concentrations of organophosphate flame retardant metabolites, fertility measures, and pregnancy outcomes among couples 

undergoing in vitro fertilization. Environ Int. 111:232-238. https://doi.org/10.1016/j.envint.2017.12.005 [Online 17 Dec 2017]

 4 Wu H, et al. 2017. Parental contributions to early embryo development: influences of urinary phthalate and phthalate alternatives among couples undergoing 

IVF treatment. Hum Reprod. 32(1):65-75. 

 5 Dec. 2019. Monograph on the Systematic Review of Traffic-related Air Pollution and Hypertensive Disorders of Pregnancy. Research Triangle Park, NC: National 

Toxicology Program. Available: https://ntp.niehs.nih.gov/ntp/ohat/trap/mgraph/trap_final_508.pdf. [Accessed 11 January 2019].

 6 Mínguez-Alarcon L, et al. 2017. Occupational factors and markers of ovarian reserve and response among women at a fertility centre. Occup Environ Med 74(6):426-431.

 7 Ferguson KK, et al. 2016. Urinary phthalate metabolite and bisphenol A associations with ultrasound and delivery indices of fetal growth. Environment Int 94: 531-537 

http://dx.doi.org/10.1016/j.envint.2016.06.013. [Online 16 June 2016]

 8 Ferguson KK, et al. 2018. Environmental phenol associations with ultrasound and delivery measures of fetal growth. Environment Int 112: 243-250. 

https://doi.org/10.1016/j.envint.2017.12.011. [Online 30 Dec 2017]

 9 Gilbert-Diamond D, et al. 2016. Relation between in utero arsenic exposure and birth outcomes in a cohort of mothers and their newborns from New Hampshire. 

Environ Health Perspect 124(8):1299–1307.

10 Rodriguez KF, et al. 2016. Effects of in utero exposure to arsenic during the second half of gestation on reproductive endpoints and metabolic parameters in female 

CD-1 mice. Environ Health Perspect 124(3):336-43.

11 Harley KG, et al. 2019. Association of phthalates, parabens and phenols found in personal care products with pubertal timing in girls and boys. Hum Reprod 

34(1):109−117.

12 Upson K, et al. 2016. Soy-based Infant Formula Feeding and Heavy Menstrual Bleeding Among Young African American Women. Epidemiology 27(5):716-25.

13 Upson K, et al. 2019. Soy-based infant formula feeding and menstrual pain in a cohort of women aged 23-35 years. Hum Reprod 34(1):148-154.

14 Upson K, et al. 2015. Early-life factors and endometriosis risk. Fertil Steril 104(4):964-9761.

15 Upson K, et al. 2016. Soy-Based Infant Formula Feeding and Ultrasound-Detected Uterine Fibroids among Young African-American Women with No Prior Clinical 

Diagnosis of Fibroids. Environ Health Perspect. 124(6):769-75. 

16 Baird DD, et al. 2013. Vitamin D and the risk of uterine fibroids. Epidemiology. 24(3):447-453.

For more information on the 

National Institute of Environmental Health Sciences, 

go to www.niehs.nih.gov.