Hello. I am Dr. David Johnson, Professor of Medicine and Chief of Gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia.
Endoscopy in a pregnant patient is something that we generally avoid, but sometimes we have to do it. Our concern comes both from the procedure and from the medications that we use. These issues also arise with postpartum patients, in women who are breastfeeding when antibiotics are indicated. The American Society of Gastrointestinal Endoscopy Standards of Practice Training Committee has guidelines[1] (first released in 2005 and updated in 2012) on endoscopy in a pregnant or breastfeeding women.
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Let me give you an overview of some of the salient points. First, if endoscopy can be postponed, it should be postponed at least until the second trimester. When we do a procedure or give medications in the first trimester, there are concerns about teratogenesis and organogenesis and subjecting the fetus to greater risk.
Second, if you do endoscopy in these patients, they should be positioned so that the gravid uterus doesn’t compress the aorta or the inferior vena cava. This means positioning pregnant patients on their left side. If you can avoid it, do not put them on their backs, either during the endoscopy or during the postprocedure recovery period.
Radiation exposure is a major concern in a fetus, with respect to both embryogenesis and future carcinogenesis. This is a concern with endoscopic retrograde cholangiopancreatography (ERCP) in a patient with biliary pancreatitis or symptomatic choledocholithiasis.
The committee recommended several ways that we could potentially minimize the radiation risk during ERCP. The first is using a shield but recognizing that the principal exposure to the fetus is not so much from direct exposure but from radiation scattered within the pregnant patient. The radiation dose should always be measured and minimized. One method is to use brief “snapshots” rather than continual fluoroscopy, using a low-dose setting.
ERCP can be performed without fluoroscopy. Selective cannulation of the biliary tree could be documented by aspiration of bile in the endoscopy catheter, sweeping the balloon through and not necessarily going back photoscopically and documenting all the sweeps.
Xem thêm : Medicamento para el vómito en niños
If you are doing electrocautery, the recommendation is that bipolar cautery is better than monopolar and should be applied with care to avoid putting the grounding pad anywhere near the fetus because the amniotic fluid can conduct a current. Care should be taken to minimize any cautery effect. If doing a biliary sphincterotomy, bipolar cautery can be applied in short bursts. The guidelines recommend postponing cautery for a monopolar polypectomy until the postpartum period. If there is any need to provide abdominal pressure, it should be done minimally and directed away from the fetus.
I would not do endoscopy on a pregnant patient without consulting the patient’s obstetrician before the endoscopy. During anesthesia and endoscopy some obstetricians may want to monitor fetal heart rate or uterine contractions. So use your obstetrician and involve them for a pre-endoscopy assessment and recommendations for monitoring and safety, as well as to review the medications you are planning to use.
Let’s talk about the medications used in endoscopic procedures. Sedation is part and parcel with endoscopy. The US Food and Drug Administration has classified drugs for use in pregnancy as category A, B, C, D, or X as follows:
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Category A: Controlled studies in women that do not demonstrate a risk to the fetus in the first trimester (and there is no evidence of a risk in later trimesters), and the possibility of fetal harm appears remote
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Category B: Either animal studies have not demonstrated a risk and there are no controlled studies in pregnant women, or animal studies have shown an adverse effect that has not been confirmed in humans.
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Category C: Either animal studies have shown an adverse effect but no controlled studies are available in humans, or no animal or human data are available. Drug should only be given if the benefit outweighs the risk to the fetus.
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Category D: There is positive evidence of harm in human studies; drug should be used only in life-threatening situations when no safer drug is available.
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Category X: Studies in animals or humans show harm and risks clearly outweigh benefits. Drug is contraindicated in pregnancy.
Xem thêm : U.S. Food and Drug Administration
With respect to sedatives, benzodiazepines are typically used in endoscopy unless you are using only propofol. Benzodiazepines are pregnancy category D drugs. The evidence that diazepam is associated with cleft lip in the fetus is very strong. Midazolam has not been associated with congenital anomalies and is the preferred agent.
With respect to narcotics, meperidine (category B) has not been shown to be teratogenic and can be used in pregnancy. Meperidine crosses the fetal blood-brain barrier but not to the extent of morphine. Meperidine is preferred over morphine or fentanyl (both category C) in pregnant patients.
Propofol seems to be safe but has not been well-studied during the first trimester. Still, it has become the drug of choice for anesthesia during endoscopy.
Other drugs that might be used during endoscopy include glucagon (category B) and simethicone (category C). Polyethylene glycol electrolyte isotonic cathartic solutions used to prepare the bowel for colonoscopy are category C. It is better to avoid colonoscopy during pregnancy if possible.
Topical anesthetics, such as lidocaine, are category B drugs. A study of 293 patients showed no fetal malformations with first trimester use of topical lidocaine.[2] The guidelines suggest that patients should gargle with the drug and spit it out rather than swallow it.
Antibiotics are occasionally used for endoscopy. We use them less frequently than in the past and very rarely in our present practice. Drugs, such as penicillin, cephalosporins, clindamycin, and erythromycin, are all viewed as safe. Drugs that should be avoided include quinolones (which can be associated with a neonatal or a fetal arthropathy), drugs that are associated with G6PD (nitrofurantoin and sulfonamide), and tetracyclines because of the mottling of the dentition. During the first trimester, metronidazole should be avoided because there is teratogenicity in rats. If it needs to be given later, it should be done in consultation with the obstetrician.
We often have questions about drugs that are safe to use in lactating women. Meperidine is excreted in breast milk and is detectable for up to 24 hours. Fentanyl is detected in a minute fashion for several hours. Although meperidine and fentanyl are both approved for use during breastfeeding, the guideline recommends using fentanyl wherever possible. Propofol, which is excreted in breast milk in minute quantities, can also be used. Midazolam is also excreted in breast milk but the effects on the infant are unknown. It is recommended that mothers do not breastfeed for 4 hours after receiving midazolam.
In summary, it is important first of all to work closely with the obstetrician. Don’t proceed with endoscopy in pregnant patients alone, and try and postpone endoscopy if possible until the second trimester. Be aware of the positional effects and the medications that you use for induction. Most standard drugs can be used during pregnancy and breastfeeding. Take a look at the guidelines the next time you have a pregnant or lactating patient, and hopefully they will steer you, the patient, and the child in good stead. I’m Dr. David Johnson.
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