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Postpartum Uterine Regression

18 Years
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Uterine Leiomyoma

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Trial Information

Postpartum Uterine Regression

Background: Uterine leiomyomas are the leading cause of hysterectomy in the United States,
accounting for over 200,000 procedures each year. Most epidemiologic studies of uterine
leiomyoma show that parity has a protective association with leiomyoma, but the mechanism is
not known. Both epidemiologic data and data from an animal model indicate that the
protective association is not an artifact resulting from reduced fertility among women with
fibroids. We hypothesize that the process of uterine regression following delivery results
in loss of small fibroids due to selective apoptosis of transformed cells and the extensive
remodeling of the entire uterus.

Study Objectives: Monitor fibroids during pregnancy and after postpartum uterine regression
to assess any loss of fibroids and change in size of fibroids.

Methods: Add a postpartum ultrasound examination to an existing epidemiologic study of
pregnant women. The parent study documents fibroid number, size, and location with a 7 week
ultrasound examination. With the additional postpartum ultrasound proposed here, data on
fibroid number, size, and location through pregnancy and postpartum uterine regression will
be collected on approximately 400 women. A subsample of 30 women will also have an MRI
after their postpartum ultrasound in order to evaluate the sensitivity of ultrasound

Significance: This study will provide the first data on fibroid change with
parturition/postpartum uterine regression for a large sample of women. If small fibroids
disappear during this time, it will document a process that results in "natural regression"
of these tumors in premenopausal women. Insights from the biology of this process may be
useful in developing treatment that could be used by nonpregnant women with fibroids to
induce tumor regression.

Inclusion Criteria


Participants in the Right From The Start Study must be 18 years old or older, pregnant,
enrolled by 10 weeks of gestation, planning to carry pregnancy to term, no plans to move
before delivery, and English speaking. Those who are found to have fibroids at either
their 7-week, or 22-week ultrasound examination are eligible for this further
postpregnancy study.

A small substudy of 30 women having MRIs to evaluate the sensitivity of the ultrasound
imaging will include only participants with a single fibroid found at the early pregnancy


Exclusion criteria for the MRI are weight greater than 250 pounds, currently pregnant,
metal of specific types in the body (an artificial hip, a clip for brain aneurysm, a
medical implant in the ear, metal fragment in the eye, or a pacemaker), history of
claustrophobia, previous severe reaction to MRI contrast, and chronic kidney disease. A
severe reaction would consist of bronchospasm (shortness of breath/difficulty breathing)
or shock (sudden loss of blood pressure). Risk is less than 1/100,000 with Gd based
contrast material. Any potential subject with a history of kidney disease will be
excluded from the study.

Type of Study:


Study Design:


Principal Investigator

Donna D Baird, Ph.D.

Investigator Role:

Principal Investigator

Investigator Affiliation:

National Institute of Environmental Health Sciences (NIEHS)


United States: Federal Government

Study ID:




Start Date:

December 2001

Completion Date:

Related Keywords:

  • Uterine Leiomyoma
  • Apoptosis
  • Environment
  • Infection
  • Inflammation
  • Leiomyoma
  • Uterine Leiomyoma
  • Uterus
  • Leiomyoma
  • Myofibroma



NIEHS, Research Triangle ParkResearch Triangle Park, North Carolina  27709