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Nausea and vomiting in pregnancy - Evidence
Evidence on antihistamines
CKS could find no evidence that the use of promethazine or cyclizine in pregnancy increases the risk of congenital malformations.
- One systematic review demonstrated no increased risk of major malformations following the use of promethazine in pregnancy (n = 1006) [Magee et al, 2002]. The authors pooled the data for all phenothiazines (including promethazine) and showed no association between phenothiazine use and the risk of malformations (RR 1.00, 95% CI 0.84 to 1.18).
- Drug exposure during pregnancy was identified from the Swedish Birth Registry and included 678 women taking promethazine only and 309 women taking cyclizine only [Kallen, 2002]. The rate of congenital malformations was 3.14% for promethazine and 3.17% for cyclizine, which did not differ from rates in the general population (3.16%).
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