11/5/06njm

**Q. Is an informed consent necessary for all x-rays in pregnant
women?**

A. No, not on routine diagnostic studies. High dose procedures are
treated case by case.

**Background**

Here is part of what ACOG says in ACOG Committee Opinion #299

1.) Women should be counseled that X-ray exposure from a single
diagnostic procedure does not result in harmful fetal effects.
Specifically, exposure to less than 5 rad has not been associated with
an increase in fetal anomalies or pregnancy loss.

4.) Consultation with an expert in dosimetry calculation may be helpful
in calculating estimated fetal dose when multiple diagnostic X-rays are
performed on a pregnant patient."

Here is what UpToDate says

"Radiation risks should be discussed with the pregnant patient,
including an explanation of the background population risk for
miscarriage, congenital anomalies, genetic disease, and growth
restriction (approximately 20, 4, 10, and 10 percent, respectively).
Consultation with a radiologist should be obtained to plan the optimum
study using the least amount of radiation or to reconstruct the amount
of radiation exposure from examinations performed prior to knowledge of
the pregnancy."

[[http://www.uptodateonline.com/utd/content/topic.do?topicKey=maternal/2119&type=A&selectedTitle=3\~37]{.underline}](http://www.uptodateonline.com/utd/content/topic.do?topicKey=maternal/2119&type=A&selectedTitle=3~37)

If the Radiologist is planning a series of high dose procedures then it
is incumbent on 'an expert in dosimetry calculation' (read as: the
Radiologist) to discuss the risks and benefits with the patient, e. g.,
not the Family Physician, OB/GYN, or clinic nurse ordering the test to
get a pre-procedure informed consent.

In those complex cases the 'expert in dosimetry calculation' discussion
can be documented in the patient's chart in paragraph manner or in a
preprinted form if the 'expert in dosimetry calculation' feels it is
necessary to document their discussion.

Bulleted points from ACOG Committee Opinion #299

**Guidelines**

The following guidelines for X-ray examination or exposure during
pregnancy are suggested:

1.  Women should be counseled that X-ray exposure from a single
    diagnostic procedure does not result in harmful fetal effects.
    Specifically, exposure to less than 5 rad has not been associated
    with an increase in fetal anomalies or pregnancy loss.

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1.  Concern about possible effects of high-dose ionizing radiation
    exposure should not prevent medically indicated diagnostic X-ray
    procedures from being performed on a pregnant woman. During
    pregnancy, other imaging procedures not associated with ionizing
    radiation (e.g, ultrasonography, MRI) should be considered instead
    of X-rays when appropriate.

2.  Ultrasonography and MRI are not associated with known adverse fetal
    effects.

3.  Consultation with an expert in dosimetry calculation may be helpful
    in calculating estimated fetal dose when multiple diagnostic X-rays
    are performed on a pregnant patient.

4.  The use of radioactive isotopes of iodine is contraindicated for
    therapeutic use during pregnancy.

5.  Radiopaque and paramagnetic contrast agents are unlikely to cause
    harm and may be of diagnostic benefit, but these agents should be
    used during pregnancy only if the potential benefit justifies the
    potential risk to the fetus.

Guidelines for diagnostic imaging during pregnancy. ACOG Committee
Opinion No. 299. American College of Obstetricians and Gynecologists.
Obstet Gynecol 2004;104:647--51.

**Some practical issues:**

-Imaging teams are reluctant to x-ray any pregnant patient for any
reason.  The medical necessity needs to be there and be real.

-Ask female patients of child bearing age if there is a chance they
might be pregnant.  This applies whether they are presenting for plain
films, CT or MRI.

 

-Informed consent is not standard for routine plain films.  Do shield
patients when applicable to minimize exposure to the fetus and gonads. 
The techs are supposed to annotate or record this in the RPMS record
when they do.

 

-If you get a positive PPD new conversion result in a prenatal patient,
CXR\'s are not necessary for asymptomatic pregnant patients. A CXR can
be completed immediately post partum

 

-It is reasonable to get informed consent for contrast enhanced CT\'s,
but the consent form focuses on the intravenous contrast and does not
include a section on risk of ionizing radiation.  The imaging team
assumes the ordering physician has taken all of this into account before
ordering any x-ray exam, but especially in CT where exposure levels are
much higher.  

-It is reasonable to create a form specifically worded for higher dose
CT(s) in pregnancy.  Fortunately the clinical setting for pregnant
patients having a CT is usually trauma and once in a while to rule out a
cerebral hemorrhage or even more rarely pulmonary embolus.  In those
cases, maternal risk out weighs the risk of exposing the fetus to
ionizing radiation\...either direct or by scatter.  Imaging teams have
to rely on the ordering clinicians to help evaluate relative risk and
benefit.

 

-Interestingly, although MRI is probably safe in pregnancy, many
radiologists do consent them for MRI exams, and actually have a special
consent form which they sign regarding the uncertainties of its effect,
especially in the first trimester. 

**In summary:**

-If a pregnant patient is getting multiple high dose procedures, then
'an expert in dosimetry calculation' (read as: the Radiologist) should
provide consultation

-If the 'experts in dosimetry calculation' want to get an informed
consent on each pregnant patient for all x-rays themselves, then it
would be an added process with no clinical/medical legal value added.

-My suggestion is that rather than wasting their efforts on a multitude
of low risk procedures, that the 'experts in dosimetry calculation'
provide consultation only when getting multiple high dose procedures

-Lastly, if the 'experts in dosimetry calculation' (read as: the
Radiologist at PIMC) feel an informed consent is needed for a particular
procedure or series of procedures, then it should be performed by an
'expert in dosimetry calculation' e. g., not the Family Physician,
OB/GYN, clinic nurse, etc...