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Failure to discontinue losartan during pregnancy

by Rachel Pollock, Marketing and Brand Specialist, and 
Ariana Gutierrez, MSN, RN, Risk Management Representative

On January 5, a 30-year-old woman came to her family physician with a positive pregnancy test. She was estimated to be at six to eight weeks gestation. Her medical history included hypertension and vitamin D deficiency. Her medications included losartan potassium 100 mg daily. The family physician had discussed possible medication side effects and drug interactions with the patient during previous visits. 

Physician action
The family physician instructed her to contact her obstetrician (OB) to discuss the continuation of vitamin D and losartan during pregnancy. The patient agreed to follow up with her OB.

As documented by the OB, the patient’s medical records consistently included losartan among her medications throughout February and into April. There was no indication that the OB advised the patient to discontinue losartan or informed her of potential risks associated with its use during pregnancy.

On May 29, an electronic refill of losartan was rejected due to the requirement for a visit with her family physician before refills could be issued. From June 1 to June 2, a series of messages were exchanged between the patient and the family physician’s office requesting losartan. In the message dated June 1, the patient noted her pregnancy and OB care. She was instructed by the office to keep her appointment with the family physician and to bring the labs from her OB. The patient was given three tablets of losartan until her upcoming visit.

During a June 4 visit, the family physician noted that the patient had an intrauterine pregnancy (IUP) and confirmed that it was acceptable for her to continue taking losartan per the OB's approval. Her medication history still included losartan.

On June 26, during a visit to the OB, the patient was diagnosed with gestational diabetes. Due to maternal obesity, a repeat ultrasound revealing anhydramnios. The fetal kidneys appeared normal. The patient’s blood pressure was high, leading to her admission to the hospital's labor and delivery unit. Upon admission, her blood pressure readings were in the severely elevated range.

Upon the patient’s admission, the OB stated that she just learned that the patient had been taking losartan prescribed by her family physician. She immediately discontinued the patient’s losartan and ordered nifedipine for the patient’s hypertension. 

Following consultation with maternal fetal health specialists, the decision was made to manage the patient expectantly. Subsequent ultrasounds revealed that the fetus was in breech position during the hospital admission. Expectant management continued until July 3, when the patient’s blood pressure increased dangerously.

Due to the patient’s hypertension with severe features and fetal breech presentation, the OB opted to perform a cesarean delivery. The patient was informed of the risks associated with anhydramnios, including lung hypoplasia and kidney failure. She tolerated the surgery but required additional nifedipine for high blood pressure in the postpartum period.

A baby boy was born on July 3 at 31 weeks with Apgar scores of 2/6/8 and a weight of four pounds, four ounces. He was immediately transferred to intensive care due to acute renal failure, hypoplastic lungs, a congenital heart defect, and intraparenchymal brain hemorrhages. On July 9, he was transferred to the children’s hospital. 

His admission to the children’s hospital revealed multiple issues, including renal problems, enlarged kidneys consistent with autosomal recessive polycystic kidney disease, cardiac abnormalities, and thrombocytopenia.

Since his initial hospitalization, the infant has required ongoing medical care and multiple treatments. His medical issues have included complications associated with hypertrophic cardiomyopathy, chronic liver disease, and peritoneal dialysis. His condition necessitated evaluation for renal transplant. 

The attending nephrologist noted that the renal insufficiency was likely caused by exposure to losartan in utero stating, “Many of the medical abnormalities are likely related to intrauterine ARB exposure, which has been documented in case reports to cause oligohydramnios, fetal growth retardation, pulmonary hypoplasia, limb contractures, calvarial hypoplasia and renal damage.”

A lawsuit was filed against the family physician, alleging negligence in continuing to prescribe losartan to the patient while pregnant as well as failure to prescribe safer antihypertensives and failure to warn her of the risks involved in taking losartan while pregnant. 

Legal implications
According to TMLT consultants, the reasonable action for the family physician would have been to stop the patient’s losartan immediately when he became aware of the patient’s pregnancy. 

The plaintiff stated that the family physician breached the standard of care by continuing the patient’s losartan. The standard of care required discontinuing ACE inhibitors and ARBs early in pregnancy and prescribing an alternative medication if necessary.  

Losartan is classified by the Food and Drug Administration (FDA) as a pregnancy risk category D medication. With these medications, there “is positive evidence of human fetal risk based on adverse reaction data from investigational or marketing experience or studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.” (1) The family physician testified that he was unaware of Losartan’s FDA classification and that it carried a “black box warning.” 

Other consultants were critical of the family physician’s decision to defer the continuation of losartan to the obstetrician. However, they argued the responsibility may have ultimately been with the OB, as the patient was under her care for the duration of the pregnancy. The consultants also noted that there was no documentation of any direct communication between the family physician and the OB. 

The patient testified that she contacted the OB’s office and provided a nurse with a list of her prescriptions, including losartan and vitamin D.  The nurse spoke with the OB and then told the patient to “continue what you’re taking.” 

The patient visited the OB in March and was told by her to continue the medications without any warnings about the risks of taking losartan. 

This case was settled on behalf of the family physician; the OB also settled with the plaintiffs.

Risk management considerations
A 2015 study of attending physicians and residents showed that 36.3 percent of physician participants could correctly identify medications with black box warnings, with attending physicians performing better than residents. The residents, however, did perform better with increasing years of training. (2)

According to the FDA, more than 400 medications currently carry black box warnings. While unlikely that a physician could memorize this entire list, it is important that providers stay up to date on medications with box warnings that they may prescribe regularly in their specialty. (3)

Electronic health record systems may offer tools and alerts to assist with identifying black box warnings or contradictions of medications.  These tools can assist physicians in making safe and informed prescribing decisions. 

Although the family physician reviewed the risks and benefits of the losartan with the patient in previous visits, he needed to review them again when considering a pregnancy. Even if a patient has been taking a medication for months or years, when there are changes in their health status, dosage, or frequency it may be necessary to re-evaluate and re-educate the patient on the medication. 

The importance of reviewing patient medications at every visit is emphasized in this case. This should be a shared duty between the medical assistant or nurse and the physician. When reviewing a patient's medication record, looking for duplicates, discontinued medications, or dose changes that need updating can all help to ensure there are no errors that could be harmful to the patient.

The lack of communication between the family physician and the obstetrician contributed to the outcome of this case. When the family physician received the request for refill, it should have alerted him that he was still the managing provider and that the OB had not taken over treatment of the patient’s hypertension. Ideally, the family physician should also have contacted the OB directly when the patient was referred to her OB for prenatal care.

The OB’s nurse was aware of the patient’s medications, but they were overlooked by the physician. Had the family physician reached out to the OB in June when the refill request came in, the dangers of continuing losartan might have been identified and addressed. 


  1. U.S. Department of Health & Human Services. Chemical Hazards Emergency Medical Management. FDA Pregnancy Categories. Updated September 5, 2023. Available at Accessed September 15, 2023. 

  2. Smollin CG, Fu J, Levin R. Recognition and Knowledge of Medications with Black Box Warnings Among Pediatricians and Emergency Physicians. Journal of Medical Toxicology: Official Journal of the American College of Medical Toxicology. 2016. Available at Accessed October 4, 2023. 

  3. Boxed warnings: What to know. Medical News Today website. Reviewed July 4, 2023. Available at Accessed October 4, 2023. 


Rachel Pollock can be reached at

Ariana Gutierrez can be reached at