What is the safety of second-generation antihistamines (e.g. loratadine) during pregnancy?

From the Guidelines

Second-generation antihistamines, such as loratadine and cetirizine, are considered safe to use during pregnancy, with no significant increase in congenital malformations or adverse pregnancy outcomes reported in large observational studies. When considering the safety of second-generation antihistamines during pregnancy, several factors are important to note:

• The most critical time for concern about potential congenital malformation due to medication use is the first trimester, when organogenesis is occurring 1.
• A sufficient amount of human observational data has been accumulated to demonstrate safety for second-generation antihistamines, such as loratadine, during pregnancy 1.
• Large birth registries, case-control studies, and cohort studies have confirmed the safety of second-generation antihistamines used during the first trimester of pregnancy 1.
• Both first-generation and second-generation antihistamines have excellent safety records and do not show a significant increase in congenital malformations when used during the first trimester, although caution is still advised for a few antihistamines 1.
• More recent studies have also reported that H1-antihistamines, in general, have not been linked to increased risk of congenital anomalies 1. Some key points to consider when prescribing second-generation antihistamines during pregnancy include:
• Loratadine and cetirizine are preferred options due to their extensive safety data in pregnancy 1.
• These medications can be used at standard adult dosing: loratadine 10mg once daily or cetirizine 10mg once daily for allergy symptoms.
• Consistent use throughout pregnancy is acceptable if needed.
• Second-generation antihistamines are recommended over first-generation options because they don't cross the blood-brain barrier significantly, causing less drowsiness and fewer anticholinergic effects.
• Fexofenadine is another reasonable option, though it has slightly less pregnancy safety data than loratadine and cetirizine.
• When prescribing, consider starting with the lowest effective dose and using only when symptoms warrant treatment.

From the FDA Drug Label

If pregnant or breast-feeding, ask a health professional before use. The FDA drug label does not answer the question.

From the Research

Safety of Second-Generation Antihistamines During Pregnancy

• The safety of second-generation antihistamines, such as loratadine, during pregnancy is a topic of discussion in various studies 2, 3.
• According to a study published in 1999, second-generation antihistamines have a more favorable risk-benefit ratio compared to first-generation antihistamines, but their use should be avoided during pregnancy and they should never be administered to nursing mothers 2.
• However, a study published in 2003 suggests that in pregnant women who cannot tolerate first-generation antihistamines, the use of a second-generation agent, such as loratadine or cetirizine, should be considered 3.
• There is no direct evidence in the provided studies regarding the safety of loratadine during pregnancy, but studies suggest that second-generation antihistamines can be used in pregnant women under certain circumstances 3, 4.
• It is essential to note that the use of any medication during pregnancy should be carefully evaluated, and the benefits should outweigh the potential risks to the fetus 5.

Key Considerations

• Second-generation antihistamines, including loratadine, are considered to have a lower risk of adverse effects compared to first-generation antihistamines 2, 4.
• The decision to use second-generation antihistamines during pregnancy should be made on a case-by-case basis, taking into account the individual patient's needs and medical history 3.
• More research is needed to fully understand the safety and efficacy of second-generation antihistamines during pregnancy 3, 4.