Background:  Heroin availability and purity decreased precipitously in Australian markets between 2000 and 2001. This led to increased use of non‐opiate drugs in the general community but whether pregnant drug users and their newborn infants were affected remains unknown.
Aim:  To determine if perinatal drug exposure and outcomes are affected by changes in street drug availability.
Methods:  Retrospective review was carried out of known drug‐exposed mothers delivering live‐born infants at the Royal Hospital for Women, Randwick, Australia (n = 316). Study periods were divided into preshortage (A = 1998–2000, n = 79), shortage (B = 2001–2002, n = 92) and post‐shortage (C = 2003–2006, n = 122) periods. Cannabis‐only users were excluded (n = 23).
Results:  The percentage of confined women who admitted to using heroin decreased significantly (65%(A) vs 34%(B), P < 0.01) as did women on methadone programmes (90%(A), 80%(B), 75%(C), P = 0.024). The use of cocaine (7% (A) vs 33% (B), P = 0.031) and amphetamines (4% (A) vs 22% (C), P = 0.01), tripled. Most infants were born full‐term and healthy but the duration of infant hospitalisation increased significantly from (median [interquartile range]) 8 [10, 38](A) to 13 [7, 23](C) days (P < 0.01). Approximately 50% of infants required withdrawal treatment but more needed phenobarbitone as an adjunct to morphine during the shortage (4/80 (0.5%) vs 15/93 (16%), P = 0.026), probably because of increased exposure to non‐opiate drugs. Conclusions:  The types of drugs used by pregnant drug users follow street trends and may affect infant hospitalisation and withdrawal treatment. Of concern is the rise in amphetamine‐use and there needs to be increased vigilance for similar trends, especially in previously unidentified drug users.