Off-Label Use of Ondansetron in Pregnancy in Western Australia
Table 1
Maternal characteristics of women dispensed ondansetron any time during pregnancy.
Ondansetron
Nonondansetron = 96,447
OR (95% CI)
%
%
Caucasian
238
94.8
81,888
84.9
3.3 (1.9–5.7)
Did not smoke during pregnancy
234
93.2
79,731
82.8
2.9 (1.8–4.7)
Parity > 1
177
70.5
67,267
69.7
1.0 (0.8–1.4)
Multiple birth
11
4.4
1,585
1.6
2.7 (1.5–5.0)
Privately insured
195
77.7
36,012
37.3
5.8 (4.3–7.9)
Not single
245
98.0
87,654
91.3
4.7 (1.9–11.4)
Previous preterm delivery
10
5.6
5,589
8.3
0.7 (0.3–1.3)
SEIFA
<25%
21
10.0
19,038
24.7
1
25–50%
40
24.5
19,322
28.8
1.9 (1.1–3.2)
50–75%
88
53.3
29,347
37.9
2.7 (1.7–4.4)
>75%
86
36.6
18,981
21.9
4.1 (2.5–6.6)
Labour and delivery characteristics
Threatened preterm labour, <37 wks*
9
3.6
2,267
2.4
2.3 (1.0–4.9)
Preterm birth, <37 wks*
34
13.5
7,872
8.2
1.4 (0.7–2.5)
Obstetrician at delivery**
183
72.9
39,399
40.9
1.7 (1.2–2.4)
Epidural/caudal anaesthetic
167
66.5
45,272
46.9
2.2 (1.7–2.9)
Caesarean
111
44.2
30,947
32.1
1.7 (1.3–2.2)
Previous Caesarean
52
20.7
13,204
13.7
1.7 (1.2–2.4)
Elective Caesarean**
76
30.3
17,510
18.2
1.3 (1.0–1.8)
Emergency Caesarean
35
13.9
13,438
13.9
1.0 (0.7–1.4)
Postpartum haemorrhage 500 mls***
18
7.2
8,844
9.2
1.2 (0.7–2.0)
Induced labour
87
34.7
28,475
29.6
1.3 (1.0–1.6)
Threatened abortion, <20 wks
15
6.0
4,964
5.1
1.2 (0.7–2.0)
Analgesia provided
112
44.6
35,289
36.6
1.4 (1.1–1.8)
Artificial rupture of membranes
75
29.9
22,213
23.0
1.4 (1.1–1.9)
Pregnancy characteristics
Admitted to hospital for HG**
88
35.1
1,646
1.7
32.8 (25.1–42.9)
Fertility treatment
11
4.4
2,340
2.4
1.8 (1.0–3.4)
Urinary tract infection
13
5.2
3,251
3.4
1.6 (0.9–2.7)
Preeclampsia
17
6.8
4,343
4.5
1.5 (0.9–2.5)
Amniocentesis
9
3.6
2,573
2.7
1.4 (0.7–2.6)
Other complications of pregnancy
96
38.2
18,782
19.5
2.6 (2.0–3.3)
Adjusted for previous preterm birth, maternal age, smoking during pregnancy, SEIFA, parity, private health insurance, and multiple birth.
**Adjusted for private health insurance and multiple birth.
***Adjusted for Caesarean delivery, private health insurance, and multiple birth.
