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Medication Errors in Adults—Case #7: Pregnancy

Medication Errors in Adults—Case #7: Pregnancy

Medication errors may occur at any point in the health care system. Obtaining a true estimate of the number of errors is difficult, but preventable medication errors are known to increase patient harm and total health care costs.1

This series will highlight some of the most important drug errors and address methods to decrease the risk of them occurring. In the first article, I addressed a common error associated with warfarin.2 The second article focused on a common error that involved acetaminophen and duplicate therapy.3 In the third article, I addressed a common error associated with duplicate therapy.4 The fourth article discussed a common error with chemotherapy drug interactions.5 In the fifth article, I looked at potential errors related to pharmacotherapy in patients with renal insufficiency.6 The sixth article described errors associated with insulin.7 In this seventh article, I describe an error associated with pregnancy.

Case #7: Pregnancy

A 34-year-old woman with a past medical history of type 2 diabetes mellitus (DM) presents to the clinic for follow-up of her DM. Her DM has been well controlled with diet, exercise, and weight loss, and her last 2 hemoglobin A1c levels have been less than 6.5% (American Diabetes Association [ADA] goal, less than 7.0%). Her blood pressure is uncontrolled at 152/84 mg/dL (ADA goal, less than 140/80 mg/dL) in clinic today (148/82 mg/dL at the last clinic visit) and it is determined to start therapy with lisinopril, 10 mg/d, because of her history of DM. At the conclusion of the visit, the patient mentions that she also would like to have a pregnancy test because she thinks she also may be pregnant.

What is the problem in this scenario?


Pregnancy, planned or not, can present challenges to physicians treating patients who have chronic diseases, such as DM. Along with control of the disease state come important concerns regarding the use of certain medications. About 90% of pregnant women report the use of at least 1 medication; 70% report the use of at least 1 prescription medication.8 Although not every medication may be harmful to the fetus, many can be, and in others, the risk is simply not known. Understanding the risks associated with medication use in pregnancy can help prevent medication errors and unnecessary complications.

About 16% of new diagnoses of DM are made in patients aged 18 to 39 years.9 This includes a large number of women with childbearing potential who may have a diagnosis of type 2 DM and associated conditions, such as hypertension and dyslipidemia. Multiple medications may be needed to control these patients, and physicians should be aware of the risks associated with medications used to treat these conditions, such as ACE inhibitors, which often are first-line antihypertensives in patients with DM, and statins, which also are widely recommended for patients with DM.

In the case above, the patient has a diagnosis of hypertension and lisinopril, a common and appropriate first-line antihypertensive medication especially for patients with a history of DM, is prescribed. The patient also thinks she is pregnant, which could be concerning because lisinopril, an ACE inhibitor, is listed as pregnancy category D—meaning that existing adverse reaction data from investigational or marketing experience or studies in humans show positive evidence of human fetal risk.10

There are conflicting data regarding the harm of lisinopril taken in the first trimester; however, use during the second and third trimesters is associated with documented fetal risk.10-12 In addition, statins, which are listed as category X in pregnancy and are contraindicated because studies have shown evidence of fetal harm, often are prescribed for patients with DM.13

To prevent exposure to these medications and potential harm to the patient or baby, the health care team should obtain an accurate medication and medical history at each visit. In patients of childbearing age, and especially in patients who are receiving medications known to be problematic in pregnancy, verification of pregnancy and lactation status should be obtained at each visit.

Patients of childbearing age should be counseled regarding the risks associated with each medication and empowered to contact their physician immediately if they become pregnant or plan to become pregnant. In addition, patients should be made aware of over-the-counter medications that may be harmful in pregnancy and the resources available to check the safety of medications in pregnancy.


1. Institute of Medicine. To Err Is Human: Building a Safer Health System. Washington, DC: National Academy Press; 1999.

2. Medication errors in adults—Case #1: warfarin. July 29, 2013.

3. Medication errors in adults—Case #2: acetaminophen. August 21, 2013.

4. Medication errors in adults—Case #3: duplicate therapy. September 24, 2013.

5. Medication Errors in Adults—Case #4: chemotherapy drug interactions. October 25, 2013.

6. Medication Errors in Adults—Case #5: renal insufficiency. November 25, 2013.

7. Medication Errors in Adults – Case #6: insulin. December 17, 2013.

8. Centers for Disease Control and Prevention. Use of Medications in Pregnant Women. Accessed January 12, 2014.

9. Centers for Disease Control and Prevention. Distribution of Age at Diagnosis of Diabetes Among Adult Incident Cases Aged 18–79 Years, United States, 2011. Accessed January 15, 2014.

10. Package insert – Lisinopril.

11. Cooper WO, Hernandez-Diaz S, Arbogast PG, et al. Major congenital malformations after first-trimester exposure to ACE inhibitors. N Engl J Med. 2006;354:2443-2451.

12. Walfisch A, Al-maawali A, Moretti ME, et al. Teratogenicity of angiotensin converting enzyme inhibitors or receptor blockers. J Obstet Gynaecol. 2011;31:465-472.

13. Package insert – atorvastatin.

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