Patterns of prescription medicine dispensing before and during pregnancy in New Zealand, 2005–2015

OBJECTIVE: To describe prescription medicine dispensing before and during pregnancy in New Zealand, 2005–2015. METHODS: Members of the New Zealand Pregnancy Cohort were linked with their dispensing records in a national database of prescription products dispensed from community pharmacies. We identified the proportion of pregnancies during which at least one prescription medicine was dispensed, the number of different medicines used and the most commonly dispensed medicine groups both during pregnancy and in the 270 days before conception. Dispensing during pregnancy was assessed by several maternal characteristics. RESULTS: 874,884 pregnancies were included. Over the study timeframe, the proportion of pregnancies exposed to a non-supplement prescription medicine increased from 38.5% to 67.2%. The mean number of different non-supplement medicines dispensed during pregnancy increased from 2.5 to 3.2. Dispensing during pregnancy was weakly associated with body mass index, smoking status and ethnicity. Pregnancy exposure was highest for Antibacterials (26.0%), Analgesics (16.7%) and Antinausea & Vertigo Agents (11.0%). CONCLUSIONS: From 2005–2015, both the proportion of exposed pregnancies and the number of different medicines dispensed to pregnant women in New Zealand increased.