Workpla

Hazards on 

Reproduc

Health

National Institute for Occupational Safety and Health
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dorsement by the National Institute for Occupationa

and Health.

Copies of this and other NIOSH documents are availa

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http://www.cdc.gov/niosh

DHHS (NIOSH) Publication No. 99–10

February 1999

This document is in the public domain and may be f

copied or reprinted.
INTRODUCTION

Many factors can affect a woman’s reproductive

health and her ability to produce healthy childre

know that the health of an unborn child can suff

woman fails to eat right, smokes, or drinks alcoh

during pregnancy. However, we know very little

about the cause of most reproductive health prob

such as infertility, miscarriage, and birth defects

do know that some workplace hazards can affec

woman’s reproductive health, her ability to beco

pregnant, or the health of her unborn children.

This document answers the following questions

u What are reproductive hazards for female

workers?

u How does the female reproductive system w

u What reproductive problems might be caus

workplace exposures?

u How are workers and their babies exposed?

u How are families exposed?

u How can exposures be prevented?

u What additional information is available 

NIOSH?

1

INTRODUCTION

Many factors can affect a woman’s reproductive

health and her ability to produce healthy childre

know that the health of an unborn child can suff

woman fails to eat right, smokes, or drinks alcoh

during pregnancy. However, we know very little

about the cause of most reproductive health prob

such as infertility, miscarriage, and birth defects

do know that some workplace hazards can affec

woman’s reproductive health, her ability to beco

pregnant, or the health of her unborn children.

This document answers the following questions

u What are reproductive hazards for female

workers?

u How does the female reproductive system w

u What reproductive problems might be caus

workplace exposures?

u How are workers and their babies exposed?

u How are families exposed?

u How can exposures be prevented?

u What additional information is available 

NIOSH?
Substances or agents that affect the reproductive

health of women or men or the ability of couple

have healthy children

are called reproductive

hazards. Radiation,

some chemicals, certain

drugs (legal and illegal),

cigarettes, some viruses,

and alcohol are examples of reproductive hazards. This pamphlet

focuses on reproductive

hazards in the workplace

that affect women and

their ability to have

healthy children. For information about a pamphlet describing male

reproductive hazards, see page 18.

The harmful effects of a few agents found in the

workplace have been known for many years. Fo

ample, more than 100 years ago, lead was discov

to cause miscarriages, stillbirths, and infertility i

2

What are Reproductive Hazards for

Female Workers?
female pottery workers. Rubella (German measl

was recognized as a major cause of birth defects 

the 1940s. However, the causes of most reprodu

health problems are still not known. Many of the

problems—infertility, miscarriage, low birth

weight—are fairly common occurrences and aff

working and nonworking women.

A reproductive hazard could cause one or more

health effects, depending on when the woman is 

posed. For example, exposure to harmful substa

during the first 3 months of pregnancy might cau

birth defect or a miscarriage. During the last 6 mo

of pregnancy, exposure to reproductive hazards 

slow the growth of the fetus, affect the developm

of its brain, or cause premature labor. Reproduct

hazards may not affect every worker or every pr

nancy.

Table 1 lists chemical and physical reproductive 

ards for women in the workplace. The list is not 

plete and is constantly being revised. Therefore, 

not assume that a substance is safe if it is missin

from the list.

Table 2 lists viruses and other disease-causing (in

tious) agents that are found in some workplaces a

that have harmful reproductive effects in pregnan

women.

3
Table 1. Chemical and physical agents th

reproductive hazards for women in the wor

Agent Observed effects

Pote

expose

Cancer treatment

drugs (e.g.,

methotrexate)

Infertility, miscarriage,

birth defects, low

birth weight

Health car

pharmac

Certain ethylene glycol

ethers such as

2-ethoxyethanol

(2EE) and

2-methoxyethanol

(2ME)

Miscarriages Electronic 

conducto

Carbon disulfide (CS2) Menstrual cycle

changes

Viscose ra

Lead Infertility, miscarriage,

low birth weight,

developmental

disorders

Battery ma

solderer

radiator 

bridge re

firing ran

home re

Ionizing radiation (e.g.,

X-rays and gamma

rays)

Infertility, miscarriage,

birth defects, low

birth weight, developmental disorders,

childhood cancers

Health car

dental p

atomic w

Strenuous physical

labor (e.g., prolonged standing,

heavy lifting)

Miscarriage late in

pregnancy, premature delivery

Many type

4
Table 2. Disease-causing agents that are rep

hazards for women in the workplace

Agent

Observed

effects

Potentially

exposed

workers

Pr

m

Cytomegalovirus

(CMV)

Birth defects, low

birth weight,

developmental

disorders

Health care

workers, workers in contact

with infants

and children

Good 

pra

as 

ing

Hepatitis B

virus

Low birth weight Health care

workers

Vacc

Human

immunodeficiency

virus (HIV)

Low birth weight,

childhood

cancer

Health care

workers

Prac

sal 

Human

parvovirus

B19

Miscarriage Health care

workers, workers in contact

with infants and

children

Good 

pra

as 

ing

Rubella

(German

measles)

Birth defects,

low birth weight

Health care

workers, workers in contact

with infants

and children

Vacc

fore 

if n

imm

ToxoplasmosisMiscarriage,

birth defects,

developmental

disorders

Animal care

workers,

veterinarians

Good 

pra

as 

ing

Varicellazoster virus

(chicken

pox)

Birth defects, low

birth weight

Health care

workers, workers in contact

with infants

and children

Vacc

fore 

if n

imm

5
Workers with immunity through vaccinations or 

lier exposures are not generally at risk from dise

such as hepatitis B, human parvovirus B19, Germ

measles, or chicken pox. But pregnant workers w

out prior immunity should avoid contact with in

fected children or adults.

Workers should also use good hygienic practice

such as frequent handwashing to prevent the spr

of infectious diseases among workers in elemen

schools, nursery schools, and daycare centers. In 

dition, they should use universal precautions—s

as glove wearing and safe disposal of needles—

protect against disease-causing agents found in b

To understand how reproductive hazards can aff

woman’s reproductive health and her ability to h

healthy children, it is helpful to understand how 

female reproductive system works.

The main reproductive tissues in women are the 

ries, uterus, and fallopian tubes. The functions 

these tissues are largely controlled by hormones

6

How Does the Female Reproductive

System Work?
produced by the brain and the pituitary gland. 

mones are chemicals that are formed in the body 

circulate in the blood. These hormones regulate 

menstrual cycle, pregnancy, and the production 

breast milk. Estrogen and progesterone—the s

hormones—are produced by the ovaries. These 

mones are responsible

for sexual development and for preparing the uterine wall

to hold and nourish

a fertilized egg

every month. These

sex hormones also

contribute to the

basic health of the

heart, bones, liver,

and many other tissues. Finally, during

pregnancy the

placenta produces a

hormone (human

chorionic gonadotropin, or hCG) that

signals the body to

support the pregnancy.

A woman is born with all of the eggs that she wi

ever have. Therefore, if her eggs are damaged or

7

Uterus

Ovary

Fallopian tube

Pituitary gland

Brain
destroyed, she will not be able to replace them. A

puberty, a woman begins to have menstrual cycl

which enable her to release an egg each month f

one of her ovaries. Each cycle begins with a few 

of menstrual flow. When each

new cycle begins, a new

egg starts to grow. After 2 to 3 weeks, a

mature egg (ovum)

is released from the

ovary into the fallopian tubes, where it

might be fertilized

by one of the many

sperm that may surround it.

If the egg is not fertilized, it will die and leave th

body about 2 weeks later in the woman’s menstr

flow. Then the process begins again with a new 

strual cycle.

If the egg is fertilized, the complex process of re

duction continues. The fertilized egg travels for 

a week down the fallopian tube to reach the uter

where it attaches to the wall. A specialized tissu

called the placenta forms between the uterus an

newly developing fetus. The placenta transfers o

gen and nutrients from the mother to the fetus. D

ing the first 3 months of pregnancy (first trimest

8
the major fetal organs are formed. During the re

der of the pregnancy, these organs mature and the 

tus grows rapidly.

Only a few substances (some viruses, chemicals

drugs) are known to cause reproductive health p

lems. Scientists are just beginning to discover ho

workplace exposures might cause reproductive p

lems. The following problems may be caused by

workplace exposures:

u Menstrual cycle effects

u Infertility and subfertility

u Miscarriage and stillbirths

9

What Reproductive Hazards Might B

Caused by Workplace Exposures?

Fallopian tube

Ovary

Placenta

Uterus

Fetus
u Birth defects

u Low birth weight and premature birth

u Developmental disorders

u Childhood cancer

Each problem is discussed in more detail in the 

lowing sections.

Menstrual Cycle Effects

High levels of physical or emotional stress or ex

sure to chemicals such as carbon disulfide may d

rupt the balance between the brain, pituitary, and

ovaries. This disruption can result in an imbalan

estrogen and progesterone, and lead to changes i

menstrual cycle length and regularity and ovulat

Because these sex hormones have effects throug

a woman’s body, severe or long-lasting hormone 

balances may affect a woman’s overall health.

Infertility and Subfertility

About 10% to 15% of all couples are unable to c

ceive a child after 1 year of trying to become pre

nant. Many factors can affect fertility, and these

factors can affect one or both partners. Damage 

woman’s eggs or the man’s sperm, or a change i

hormones needed to regulate the normal menstru

cycle are just a few things that can cause problem

with fertility.

10
Miscarriage and Stillbirths

About 1 in every 6 pregnancies ends in a miscar

riage—the unplanned termination of a pregnanc

Miscarriages can occur very early in pregnancy, 

before the woman knows she is pregnant. Misca

riages and stillbirths occur for many reasons, suc

the following:

u The egg or sperm may be damaged so that th

cannot be fertilized or cannot survive after f

zation.

u A problem may exist in the hormone s

needed to maintain the pregnancy.

u The fetus may not have developed normally

u Physical problems may exist with the uterus 

cervix.

What causes most of these problems is still unkn

Birth Defects

A birth defect is a physical abnormality present 

birth, though it may not be detected until later. A

2% to 3% of babies are born with a major birth d

fect. In most cases, the cause of the birth defect 

known. The first 3 months of the pregnancy is a 

sensitive time of development because the intern

organs and limbs are formed during this period.

11
Many women are not aware that they are pregna

during much of this critical period.

Low Birth Weight and Premature Birth

About 7% of babies born in the United States ar

born underweight or prematurely. Poor maternal 

trition, smoking, and alcohol use during pregnan

are believed to be responsible for most of these 

Although better medical care has helped many und

weight or premature babies to develop and gr

normally, they are more likely than other babi

become ill or even die during their first year of l

Developmental Disorders

Sometimes the brain of the fetus does not develo

normally, which leads to developmental delays o

learning disabilities later in life. About 10% of c

dren in the United States have some form of dev

mental disability. Such problems are often not

noticeable at birth. They can be difficult to mea

may be temporary or permanent, and range from

mild to severe. Developmental problems may ap

as hyperactivity, short attention span, reduced le

ing ability, or (in severe cases) mental retardatio

Childhood Cancer

Ionizing radiation has caused cancer in some ch

whose mothers were exposed during pregnancy. 

12
current practice of minimizing the use of X-rays 

pregnant women, the use of newer equipment th

duces the risk of exposure, and the use of protec

shields have all helped to decrease the likelihood 

harmful radiation exposure to fetuses.

Harmful substances can enter a woman’s body

through

u breathing in (inhalation),

u contact with the skin,

u or swallowing (ingestion).

Pregnant workers and those planning to become 

nant should be especially concerned about expos

to reproductive hazards. Some chemicals (such a

cohol) can circulate in the mother’s blood, pass

through the placenta, and reach the developing f

Other hazardous agents can affect the overall he

of the woman and reduce the delivery of nutrien

the fetus. Radiation can pass directly through the

mother’s body to harm her eggs or the fetus. Som

drugs and chemicals can also pass through a mo

13

How Are Workers and

Their Babies Exposed?
body into the nursing baby through the breast m

However, breast feeding has many positive effec

Thus a woman who may be exposed to reproduc

hazards on the job should consult with her docto

other health care provider before deciding wheth

not to breast feed.

Reproductive hazards do not affect every woman 

every pregnancy. Whether a woman or her baby 

harmed depends on how much of the hazard they 

exposed to, when they are exposed, how long the

exposed, and how they are exposed.

14

Viruses

drugs

chemicals

alcohol

Harmful agents in

mother’s blood

Reduced

health

of mother

Reduced supply of

nutrients and oxygen
Workplace substances that affect female worker

their pregnancies can also harm

their families. Without knowing

it, workers can bring home

harmful substances that can

affect the health of other

family members—both

adults and children. For

example, lead brought

home from the workplace

on a worker’s skin, hair,

clothes, shoes, tool box, or

car can cause lead poisoning

in family members, especially young children.

Employers are responsible for training and prote

their workers. Employees are responsible for lea

15

How Are Families Exposed?

How Can Exposures Be Prevented?
about the hazards in their workplace, using perso

protective equipment, and following proper wor

practices. Since little is known about reproductiv

hazards in the workplace, workers should also ta

the following steps to ensure their own safety:

u Store chemicals in sealed containers when t

are not in use.

u Wash hands after contact with hazardo

substances and before eating, drinking, 

smoking.

u Avoid skin contact with chemicals.

u If chemicals contact the skin, follow the directions for washing in the material safety d

sheet (MSDS). Employers are required to h

copies of MSDSs for all hazardous material

used in their workplaces and to provide them 

workers upon request.

u Review all MSDSs to become familiar with 

reproductive hazards used in your workplac

you are concerned about reproductive hazar

the workplace, consult your doctor or health 

provider.

16
u Participate in all safety and health education, 

ing, and monitoring programs offered by 

employer.

u Learn about proper work practices and eng

ing controls (such as improved ventilation).

u Use personal protective equipment (gloves, 

rators, and personal protective clothing) to r

exposures to workplace hazards.

u Follow your employer’s safety and health 

practices and procedures to prevent exposu

reproductive hazards.

u Prevent home contamination with the follo

steps:

—Change out of contaminated clothing and 

with soap and water before going home.

—Store street clothes in a separate area 

workplace to prevent contamination.

—Wash work clothing separately from 

laundry (at work if possible).

—Avoid bringing contaminated clothing or 

objects home. If work clothes must be br

home, transport them in a sealed plastic b

17
NIOSH has published the following documents 

contain information about reproductive hazards 

workplace:

National Occupational Research Agenda

DHHS (NIOSH) Publication No. 96–115

Reproductive issues are an important part of 

National Occupational Research Agenda that is 

ing coordinated by NIOSH. The Agenda is expe

to help focus attention on reproductive issues an

increase the amount of research conducted in thi

critical area. This document discusses fertility an

pregnancy abnormalities as one of 21 priority re

search areas.

The Effects of Workplace Hazards on Ma

Reproductive Health—DHHS (NIOSH)

Publication No. 96–132

This document provides general information abo

reproductive hazards for men in the workplace. 

text explains how substances in the workplace c

cause reproductive problems and suggests metho

for preventing exposures.

18

What Additional Information is

Available from NIOSH?
19
20
IOSH

Delivering on the Nations promis

Safety and health at work

for all people

through research and prevention

To receive other information about occupational safety and heal

,

visit the NIOSH Homepage on the World Wide We

1–800–35–NIOSH (1–800–356–4674) or

http://www.cdc.gov/niosh

DHHS (NIOSH) Publication No. 99−10

T T

T

PED AR MT ENT OF HEALTH & HUMAN SERVICES USA

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES

Public Health Service

Centers for Disease Control and Prevention

Public Health Service

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

CCE

CE