Table 1.

Prevalence of exposure to antibiotics with regards to maternal characteristics in all singleton pregnancies in Sweden (2006–16)

Characteristics	Antibiotic use		No Antibiotic use		Total
	N	%	N	%	N	%
Total	98963	20.5	384743	79.5	483706	100.0
Maternal age, years
≤25	34578	35.0	107381	27.9	141959	29.3
26–30	33870	34.2	146917	38.2	180787	37.4
≥31	30515	30.8	130445	33.9	160960	33.3
Maternal BMI, kg/m2
<18.5	3109	3.2	10648	2.7	13757	2.8
18.5–24.9	56527	57.1	230877	60.0	287404	59.4
25.0–29.9	21324	21.5	81499	21.2	102823	21.3
≥30.0	11085	11.2	35611	9.3	46696	9.7
Data missing	6918	7.0	26108	6.8	33026	6.8
Tobacco consumption
Yes	25757	26.1	78914	20.5	104671	21.6
No	69117	69.8	289920	75.4	359037	74.2
Data missing	4089	4.1	15909	4.1	19998	4.1
Chronic comorbiditiesa
Yes	4015	4.1	11706	3.0	15721	3.3
No	94948	95.9	373037	97.0	467985	96.7
Exposure to other drugsb
Yes	5820	5.9	12210	3.2	18030	3.7
No	93143	94.1	372533	96.8	465676	96.3
Mother’s country of birth
Nordic	75836	76.7	299209	77.8	375045	77.5
Non-Nordic	22988	23.2	84716	22.0	107704	22.3
Data missing	139	0.1	818	0.2	957	0.2
History of Stillbirth
Yes	132	0.1	372	0.1	504	0.1
None recorded	98831	99.9	384371	99.9	483202	99.9
History of Miscarriage
Yes	16537	16.7	58841	15.3	75378	15.6
None recorded	82426	83.3	325902	84.7	408328	84.4

^aComorbidities defined as at least one recorded pre-gestation diagnosis of hypothyroidism, hyperthyroidism, hypertension and/or diabetes mellitus.

^bOther drugs defined as at least on dispensed prescription of gastric acid inhibitors [proton-pump inhibitors (PPIs), H2-receptor antagonists (H2RA)] and/or Helicobacter pylori eradication [A02B].