Pregnancy outcome after gestational exposure to loratadine or antihistamines: a prospective controlled cohort study.
BACKGROUND
Loratadine is a second-generation histamine H(1)-receptor antagonist, used in the treatment of allergic conditions. No prospective controlled trials on loratadine in human pregnancy have been published to date.


OBJECTIVE
To determine whether the use of loratadine or other antihistamines (OAH) is associated with an increased risk of major anomalies.


METHODS
Callers who were counseled by the Israeli Teratogen Information Service in regard to loratadine or OAH exposure during pregnancy were prospectively collected and followed up. Pregnancy outcome was compared among three exposure groups: loratadine, OAH, and a control group of patients who were counseled for nonteratogenic exposure, nonteratogenic controls (NTC). The OAH included astemizole, chlorpheniramine, terfenadine, hydroxyzine, promethazine, and dimetindene.


RESULTS
We followed up 210 pregnancies exposed to loratadine (77.9% in the first trimester) and 267 pregnancies exposed to OAH (64.6% in the first trimester) and compared pregnancy outcome with that of 929 NTC. The rate of congenital anomalies did not differ among the groups [loratadine: 4/175 (2.3%), OAH: 10/247 (4.0%), NTC: 25/844 (3.0%), P =.553, relative risk (RR), 0.77; 95% confidence interval (CI), 0.27 to 2.19, (loratadine vs NTC); RR, 0.56; 95% CI, 0.18 to 1.77, (loratadine vs OAH)]. The rate did not differ between those exposed to antihistamines in the first trimester and the control patients [loratadine: 1/126 (0.8%), OAH: 7/146 (4.8%), NTC: 25/844 (3.0%), P =.152, RR, 0.27; 95% CI, 0.04 to 1.94, (loratadine vs NTC); RR, 0.17; 95% CI, 0.02 to 1.33, (loratadine vs OAH)].


CONCLUSIONS
This study on the use of loratadine in human pregnancy suggests that this agent does not represent a major teratogenic risk. The study was powered to find a 3-fold increase in the overall rate of major anomalies.
Diav-Citrin
Orna
O
Israeli Teratogen Information Service, Israel Ministry of Health, Laboratory of Teratology, The Hebrew University-Hadassah Medical School, PO Box 12272, Jerusalem 91120, Israel.
Shechtman
Svetlana
S
Aharonovich
Alona
A
Moerman
Larisa
L
Arnon
Judy
J
Wajnberg
Rebecka
R
Ornoy
Asher
A
D000014:Abnormalities, Drug-Induced / Q000453:epidemiology*; D000328:Adult; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006633:Histamine Antagonists / Q000009:adverse effects*; D039563:Histamine H1 Antagonists, Non-Sedating / Q000009:adverse effects*; D006801:Humans; D007557:Israel / Q000453:epidemiology; D017336:Loratadine / Q000009:adverse effects*; D011247:Pregnancy; D011256:Pregnancy Outcome; D011264:Pregnancy Trimesters
D006633:Histamine Antagonists; D039563:Histamine H1 Antagonists, Non-Sedating; D017336:Loratadine