Phthalates Associated With Increased Risk for Preterm Births

Jenni Laidman

November 18, 2013

Ubiquitous manmade chemicals known as phthalates, found in some plastics, personal care products, and foods, among other things, are associated with increased preterm births, especially those involving spontaneous preterm deliveries, according to a study published online November 18 in JAMA Pediatrics.

Kelly K. Ferguson, MPH, from the Department of Environmental Health Sciences, University of Michigan School of Public Health, Ann Arbor, and colleagues looked at 130 cases of preterm birth and 352 randomly assigned control participants and compared levels of phthalate metabolites averaged across 3 samples taken during pregnancy in an unrelated study. In a separate analysis, the researchers looked at phthalate levels for 57 cases of spontaneous preterm birth, defined as births preceded by spontaneous preterm labor or membrane rupture. Preterm births were any that occurred at fewer than 37 weeks' gestation. Gestational age was validated by ultrasound during the first trimester. The births took place at Brigham and Women's Hospital in Boston, Massachusetts. Most study participants were white, well-educated nonsmokers; few drank during pregnancy. Nearly half were nulliparous, and about 10% used assisted-reproductive technologies. Forty-four percent of the infants were boys.

Shanna H. Swan, PhD, professor, Department of Preventive Medicine, Icahn School of Medicine at Mount Sinai, New York City, author of an accompanying editorial, writes that the study made "an important public health contribution by demonstrating a sizable impact of phthalates, a class of commonly used chemicals, on a health outcome of major public health concern: the growing burden of preterm birth."

The study authors found significant associations for the phthalate di-2-ethylhexyl phthalate (DEHP) metabolites and for metabolites of mono-n-butyl phthalate (MBP) among all preterm births and among spontaneous preterm births. The research identified additional associations for spontaneous preterm births with increased levels of mono-benzyl-butyl phthalate metabolites and MBP metabolites.

The odds ratio (OR) for all preterm births for the DEHP metabolite mono-(2-ethyl)-hexyl phthalate (MEHP) was 1.34 (95% confidence interval [CI], 1.07 - 1.68; P = .01); it was 1.65 (95% CI, 1.20 - 2.26; P=.002) for spontaneous preterm births. The OR for the DEHP metabolite mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) was 1.40 (95% CI, 1.13 - 1.74; P = .002) for all preterm births and 1.56 (95% CI, 1.15 - 2.13; P = .005) for spontaneous preterm births. For all DEHP metabolites, the summed OR was 1.33 (95% CI, 1.04 - 1.70; P = .02) for all preterm births and 1.63 (95% CI, 1.15 - 2.31; P = .006) for spontaneous preterm births.

Although the OR for several metabolites was not significant for preterm births in general, 4 were significant for spontaneous preterm births, including the DEHP metabolite mono-(2-ethyl-5-oxohexyl) phthalate (OR, 1.47; 95% CI, 1.04 - 2.08; P = .03) as well as mono-benzyl-butyl phthalate (OR, 1.41; 95% CI, 1.02 - 1.95; P = .04), mono-n-butyl phthalate (OR, 1.49; 95% CI, 1.08 - 2.06; P = .01), and mono-(3-carboxypropyl) phthalate (OR, 1.36; 95% CI, 1.01 - 1.81; P = .04).

Further, the research found that OR rose with the amount of phthalate metabolite found, with women in the 75th percentile for MEHP, MECPP, DEHP, and MBP at more than 2 times the risk for preterm birth as women in the lowest quartile. The effect was much stronger when only spontaneous preterm births were considered. For instance, women in the 75th percentile for MECPP had an OR of 5.23 for spontaneous preterm birth and an OR of 2.39 for any preterm birth. For MEHP, DEHP, and MBP, women in the highest quartile had ORs greater than 3.5 for spontaneous preterm births.

Dr. Swan suggests this stronger effect among spontaneous preterm births "makes it apparent that spontaneous deliveries are driving the effect estimates, and that the risk conveyed by phthalate exposure among the medically indicated deliveries is modest or negligible."

The authors have disclosed no relevant financial relationships.

JAMA Pediatr. Published online November 18, 2013

(Replaces Committee Opinion No. 687, February 2017)
Committee on Obstetric Practice
The American College of Nurse-Midwives endorses this document. This Committee Opinion was developed by the Committee on Obstetric Practice in
collaboration with committee members Allison S. Bryant, MD, MPH and Ann E. Borders, MD, MSc, MPH.
Approaches to Limit Intervention During Labor and
gynecologists, in collaboration with midwiv
es, nurses, patients, and those who support
them in labor, can help women meet their goals for labor and b
irth by using techniques that re
quire minimal interventions
and have high rates of patient satisfacti
on. Many common obstetric practices are of l
imited or uncertain benefit for low-risk
women in spontaneous labor. For women who are in latent labor and are not admitted to the labor unit, a process of
shared decision making is recommended to create a plan for self
-care activities and coping te
chniques. Admission during
the latent phase of labor may be necessary for a variety of reasons, including pain management or maternal fatigue.
Evidence suggests that, in addition to regular nursing care,
continuous one-to-one emotional support provided by support
personnel, such as a doula, is associated with improved outcomes for women in labor. Data suggest that for women with
normally progressing labor and no evidence of fetal compr
omise, routine amniotomy need not be undertaken unless
required to facilitate monitoring. The widespread use of co
ntinuous electronic fetal monitoring has not been shown to
significantly affect such outcomes as perinatal death and cereb
ral palsy when used for women with low-risk pregnancies.
Multiple nonpharmacologic
and pharmacologic techniques can be used to help women cope with labor pain. Women in
spontaneously progressing labor may not require routine con
tinuous infusion of intravenous fluids. For most women, no
one position needs to be mandated or proscribed. Obstetrician
gynecologists and other obstetric care providers should be
familiar with and consider using low-interventional appro
aches, when appropriate, for the i
ntrapartum management of low-
risk women in spontaneous labor. Birthing units should careful
ly consider adding family-cent
ric interventions that are
otherwise not already consider
ed routine care and that can be safely offered,
given available environmental resources and
staffing models. These family-centric in
terventions should be provided in recognition of the value of inclusion in the
birthing process for many women and their families, irre
spective of delivery mode. This Committee Opinion has been
revised to incorporate new evidence for risks and benefits of
several of these techniques and, given the growing interest
on the topic, to incorporate information on a f
amily-centered approach to cesarean birth.
Recommendations and Conclusions
The American College of Obstetricians and Gynecolo-
gists (ACOG) makes the following recommendations
and conclusions:
For a woman who is at term in spontaneous labor
with a fetus in vertex presentation, labor management
may be individualized (depending on maternal and
fetal condition and risks) to include techniques such
as intermittent auscultation and nonpharmacologic
methods of pain relief.
Admission to labor and delivery may be delayed for
women in the latent phase of labor when their status
and their fetuses
status are reassuring. The women
can be offered frequent contact and support, as well
as nonpharmacologic pain management measures.
When women are observed or admitted for pain or
fatigue in latent labor, techniques such as education
and support, oral hydration, positions of comfort, and
nonpharmacologic pain management techniques such
as massage or water immersion may be beneficial.
VOL. 133, NO. 2, FEBRUARY 2019
2018 by the American College of Obstetricians
and Gynecologists. Published by Wolters Kluwer Health, Inc.
Unauthorized reproduction of this article is prohibited.
gynecologists and other obstetric care
providers should recommend labor induction to
pregnant women with term prelabor rupture of
membranes (also referred to as premature rupture of
membranes) (PROM) who are candidates for vaginal
birth, although the choice of expectant management
for a limited time may be considered after appro-
priate counseling. Obstetrician
gynecologists and
other obstetric care providers should inform pregnant
women with term PROM who decline labor induc-
tion in favor of expectant care of the potential risks
associated with expectant management and the lim-
itations of available data. For appropriately counseled
women, if concordant with their individual prefer-
ences and if there are no other maternal or fetal
reasons to expedite delivery, the choice of expectant
management for 12
24 hours may be offered. For
women who are group B streptococci (GBS) positive,
however, administration of antibiotics for GBS pro-
phylaxis should not be delayed while awaiting labor.
In such cases, many patients and obstetrician
gynecologists or other obstetric care providers may
prefer immediate induction.
Evidence suggests that, in addition to regular nurs-
ing care, continuous one-to-one emotional support
provided by support personnel, such as a doula, is
associated with improved outcomes for women in
For women with normally progressing labor and no
evidence of fetal compromise, routine amniotomy
need not be undertaken unless required to facilitate
To facilitate the option of intermittent auscultation,
gynecologists and other obstetric care
providers and facilities should consider adopting
protocols and training staff to use a hand-held
Doppler device for low-risk women who desire
such monitoring during labor.
Use of the coping scale in conjunction with different
nonpharmacologic and pharmacologic pain man-
agement techniques can help obstetrician
gynecologists and other obstetric care providers
tailor interventions that best meet the needs of each
individual woman.
Frequent position changes during labor to enhance
maternal comfort and promote optimal fetal posi-
tioning can be supported as long as adopted positions
allow appropriate maternal and fetal monitoring and
treatments and are not contraindicated by maternal
medical or obstetric complications.
When not coached to breathe in a specific way,
women push with an open glottis. In consideration
of the limited data regarding superiority of sponta-
neous versus Valsalva pushing, each woman should
be encouraged to use her preferred and most effec-
tive technique.
Collectively, and particularly in light of recent high-
quality study findings, data support pushing at the
start of the second stage of labor for nulliparous
women receiving neuraxial analgesia. Delayed
pushing has not been shown to significantly
improve the likelihood of vaginal birth and risks of
delayed pushing, including infection, hemorrhage,
and neonatal acidemia, should be shared with nul-
liparous women receiving neuraxial analgesia who
consider such an approach.
Birthing units should carefully consider adding
family-centric interventions (such as lowered or clear
drapes at cesarean delivery) that are otherwise not
already considered routine care and that can be safely
offered, given available environmental resources and
staffing models. These family-centric interventions
should be provided in recognition of the value of
inclusion in the birthing process for many women
and their families, irrespective of delivery mode.
This Committee Opinion reviews the evidence for labor
care practices that facilitate a physiologic labor process
and minimize intervention for appropriate women who
are in spontaneous labor at term. The desire to avoid
unnecessary interventions during labor and birth is
shared by health care providers and pregnant women.
gynecologists, in collaboration with mid-
wives, nurses, patients, and those who support them in
labor, can help women meet their goals for labor and
birth by using techniques that require minimal inter-
ventions and have high rates of patient satisfaction (1).
This Committee Opinion has been revised to incorporate
new evidence for risks and benefits of several of these
techniques and, given the growing interest on the topic,
to incorporate information on a family-centered
approach to cesarean birth.
As used in this document,
low risk
a clinical scenario for which there is not clear demon-
strable benefit for a medical intervention. What consti-
tutes low risk will, therefore, vary depending on
individual circumstances a
nd the proposed interven-
tion. For example, a woman who requires oxytocin aug-
mentation will need continuous electronic fetal
monitoring (EFM) and, therefore, would not be low risk
with regard to eligibility for intermittent auscultation.
Rather than categorize laboring women as low or high
risk, the goal of this document is to ensure that the
gynecologist or other obstetric care pro-
vider carefully selects and ta
ilors labor interventions to
Committee Opinion
Limit Intervention During Labor and Birth
2018 by the American College of Obstetricians
and Gynecologists. Published by Wolters Kluwer Health, Inc.
Unauthorized reproduction of this article is prohibited.
© 2018 The Institute for Functional Medicine
Version 1
1 .
Sears ME, Genuis SJ. Environmental determinants of chronic disease and medical approaches: Recognition, avoidance, supportive therapy,
and detoxification.
J Environ Public Health.
2012;2012:356798. doi:10.1155/2012/356798.
The Importance of Detoxification
Your body produces toxins during normal body functions. It is also exposed to pollutants, or toxicants, in the air, drinking
water, and food. In Functional Medicine, detoxification or “detox” refers to the body’s process of making toxins, toxicants
and hormones less harmful. This process is also referred to as “metabolic detoxification.”
Studies on how drugs are broken down and cleared from the body have helped us to understand the detox processes. There
are well-defined pathways in the body that are responsible for changing toxicants into chemical compounds that are easier
for the body to eliminate. This happens primarily through the urine or stools.
Scientists estimate that the average adult carries within her or his body at least 700 toxins.
A newborn’s body can contain over 200 toxins.
Our society is becoming more and more toxic. The constant exposure is resulting in an ever-increasing body burden, or
toxic load, of chemicals. One of the most common exposures is to toxic farm chemicals: pesticides, herbicides, and fertilizers.
Other sources of toxicants include materials used in new construction, carpet chemicals that can off-gas into the air, paint,
household cleaners, mixed metals used in dental repairs, synthetic materials found in dental products, and even personal
hygiene products applied to face, skin, and hair. Air pollutants are found in regional or work industrial areas, primary or
second-hand smoke exposure, and auto exhaust. On a daily basis, your liver, kidneys, large intestine, lymphatic system, and
sweat glands work to reduce the body burden, or buildup, of these environmental contaminants.
Your toxic body burden is a result of three main factors:
The amount of toxicant exposures from both internal and external sources.
Your ability to produce detox enzymes for processing these compounds. This is based on your unique genetics and familial influence.
The amount of detox supporting nutrients consumed in your diet. Specific foods support the processes of changing toxic chemicals and waste products to less harmful forms and assist in their elimination.
Toxic symptoms may occur when you reach your personal limit of accumulated toxins and are not able to clear them quickly or efficiently enough. Researchers are recognizing the following symptoms related to the buildup of toxins:
Type 2 diabetes
Metabolic syndrome
Behavior and mood disorders
Neurological conditions such as tremors, headaches, and cognitive difficulties Parkinson’s and
Alzheimer’s Diseases
The goal of a clinically-directed metabolic detox protocol is to provide nutritional support for the pathways involved in the processing and elimination of toxins. A detox program results in improved symptoms and an increased sense of wellbeing for most individuals. Many who participate in a personalized detox program describe improvement in pain and fatigue levels,
enhanced cognitive function and moods, more effective and satisfying sleep cycles, and weight loss.
Non-Toxic Choices for Food Preparation,
Cookware, and Dishes
© 2018 The Institute for Functional Medicine
Version 1
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Revised January 2016.
3 .
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4 .
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and Wastewater Treatment Plants. Environ Sci Technol Lett. 2016 Oct 11;3(10):344-350.
5 .
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July 2015.
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Feb 25;173(4):317-9. doi: 10.1001/jamainternmed.2013.1569.
We often think about the quality of the foods we purchase and prepare to ensure good nutrition, but it’s also important
to consider the products we use to cook, bake, eat, and store food, as these can also potentially place our health at risk.
Certain types of kitchenware can discharge toxic fumes, chemicals, or other toxic components into our food, and over
time, these substances can accumulate in our bodies and potentially damage our health.
Plastic cutting boards may contain toxins such as bisphenol A (BPA) or phthalates, which are known to be hormone-disrupting and carcinogens (cancer-causing chemicals). Small bits of plastic containing these chemicals can also intermingle with foods as the surfaces sustain small nicks and cuts. Plastic cutting boards also have a greater tendency to accumulate bacteria in their knife-scarred surfaces than wooden ones.
Best choices:
Bamboo and wood. Always wash your wood or bamboo cutting boards with hot, soapy water and
allow to air dry.
Most popular brands of cookware used today are nonstick. Unfortunately, Teflon and other nonstick coatings
contain chemicals that can cause cancer and other health problems. When these pots and pans are heated, toxic
fumes can be produced, and some chemicals may also leach directly into your food.
Best choices:
Food-grade stainless steel, cast iron, copper, porcelain-enameled cast iron, oven-safe glass, stainless-steel lined copper, and high-quality, nontoxic ceramic-lined cookware. Additionally, look for cookware labeled as PTFE- and PFOA-free.
Plastics, including melamine dishes, may contain a variety of chemicals that have been linked to cancer and other health problems. Acidic foods and beverages can increase the leaching of chemicals into plastic dishware.
Additionally, heating and serving hot foods on plastic and melamine dishes can increase exposures to chemical compounds. Plastic and melamine dishes are often used for children, a population that is particularly vulnerable to chemical exposures.
Best choices:
Ceramic, porcelain, glass, wood, bamboo, type 304 stainless steel, and 100% food-grade silicone (this does not have plastic fillers).
Exposure to potentially harmful chemicals on a daily basis is virtually unavoidable. The majority of the 85,000 chemicals registered for production under the U.S. Toxic Substances Control Act (TSCA) were grandfathered in with little or no health and safety testing.
Medical conditions linked to toxic chemicals include obesity, metabolic syndrome, diabetes,
cardiovascular disease, Alzheimer’s and Parkinson’s, cancers, and multisystem complaints such as fibromyalgia andmultiple chemical sensitivities.
Ten categories of toxic chemicals are known to be especially prevalent, persistent, and detrimental to human and environmental health:
heavy metals: lead (Pb), mercury (Hg), arsenic (As), cadmium (Cd), aluminum (Al)
polycyclic aromatic hydrocarbons (PAHs)
plastics (phthalates)
phenols, particularly bisphenol A (BPA)
organochloride pesticides (OCs)
organophosphate pesticides (OPs)
polychlorinated dibenzo-dioxin & furan (dioxins)
polychlorinated biphenyls (PCBs)
polybrominated diphenyl ethers (PBDEs)
polyfluorinated compounds (PFCs)
Reducing Dietary Exposures
Choose organic and low-fat or no-fat animal products such as dairy, eggs, meats (PAHs, OCs, OPs, dioxins,
Choose cooking methods that are low-char and that allow animal fats to drip away, such as steaming (PAHs,
OCs, OPs, dioxins, PCBs, PBDEs).
Consult local wildlife agencies before eating freshwater fish (PCBs, dioxins, PBDEs).
Never eat farmed salmon (PCBs), avoid eating larger carnivorous fish (Hg, PBDEs, PCBs) and use the
Environmental Working Group (EWG) Good Seafood Guide.
Use glass, ceramic, or stainless steel containers for heating and storing hot food (phthalates).
Avoid plastic water bottles, travel mugs and bladder-style hydration reservoirs and do not wash plastic food or beverage containers under high heat (phthalates).
Avoid using vinyl cling wrap and only buy canned foods that are BPA-free (BPA).
Avoid high-fructose corn syrup and rice syrup (As) and processed foods containing BHT, BHA, benzoate, sulfites, and artificial colorings and sweeteners.
Choose local, seasonal, and organic produce whenever possible. Wash all fruits and vegetables using mild additive-free soap and clean water (OCs, OPs).
Choose organic versions of the EWG “Dirty Dozen” list of high-pesticide produce (OCs, OPs).
© 2015 The Institute for Functional Medicine
Reducing Exposures to Harmful Chemicals
Version 1
© 2015 The Institute for Functional Medicine
Reducing Home & Office Exposures
Consult the EWG Drinking Water Database
and consider testing your water supply. Use a NSF-certified water filter if indicated (Pb, As, Cd, trihalomethane, atrazine, benzene, etc.).
Clear water that has been standing overnight out of plumbing lines in your home or office by flushing the toilet or letting the tap run for several minutes before pouring out tap water for consumption (Pb, other metals).
Filter shower water (chlorine, OCs), and avoid using new vinyl shower curtains (phthalates).
Filter air in your bedroom and office using filters, ionizers or plants
(airborne toxins).
Cover or replace older foam furniture and consider removing old carpets and padding (PBDEs).
Remove shoes you’ve worn outside when entering your home (OPs).
Clean up broken thermometers and fluorescent bulbs with gentle sweeping and wiping up with gloves and disposable materials. Do not vacuum (Hg).
Choose fragrance- and solvent-free detergents and cleaning agents (phthalates) and consult the EWG Guide to
Healthy Cleaning.
Avoid non-stick pots and pans and do not buy stain-resistant clothing, carpet or furniture (PCBs).
Avoid products made with particleboard or medium-density fiberboard (formaldehyde, solvents).
Remove or paint over older pressure-treated wood (As). Use low- or no-VOC (volatile organic compound)
paints, glues, sealants, etc. in new construction (solvents).
With new construction, consider “baking” out noxious fumes by vacating (people, plants and animals) and setting the house heat at maximum for 24-hour cycles followed by ventilation and rechecking for fumes (solvents and other toxic chemicals).
Reducing Health Care & Personal Care Exposures
For general wellness: Stay well hydrated and consume alcohol in moderation, if at all.
Avoid acetaminophen for pain relief (especially after alcohol), and avoid taking multiple over-the-counter and prescription drugs simultaneously.
Stop smoking and avoid second-hand smoke (Cd, PAHs).
Inquire about preservatives in flu shots and vaccines and chose ones without Thimerisol (Hg).
Choose unscented, fragrance-free personal care products (phalates), avoid antiperspirants and antacids (Al), and use the EWG Cosmetics Database.
Choose composite over metallic dental fillings and be sure that your dentist follows all of the recommended IAOMT
procedures when removing silver fillings (Hg).
Avoid having two different metals (e.g., mercury and gold) in your mouth; this can create low-voltage electric currents, which accelerates metal degradation.
Reducing Work & Hobby Exposures
Identify your exposures by consulting MSDS data sheets for all chemicals you use (various toxins).
Wear and maintain all appropriate personal protective equipment and keep any work clothes that may have toxins on them separate from your home (various toxins).
1. U.S. Environmental Protection Agency:
2. Sears ME, Genuis SJ. J Environ Public Health. 2012;2012:356798
3. Environmental Working Group:
4. Environmental Working Group:
5. Environmental Working Group:
6. Claudio L. Environ Health Perspect. 2011 Oct; 119(10): a426–a427.
7. Environmental Working Group:
8. U.S. Green Building Counsil’s Green Home Guide:
9. Environmental Working Group:
International Academy of Oral Medicine and Toxicology: