Trimethoprim Use prior to Pregnancy and the Risk of Congenital Malformation: A Register-Based Nationwide Cohort Study

Table 1

Study population characteristics.

	Use of trimethoprim in the 12-week period prior to pregnancy	No use of trimethoprim in the 12-week period prior to pregnancy
	𝑛=402	𝑛=520,865
Age (year)	28.5	29.7
Parity (mean)	1.80	1.85
Household income—number (%)
<$50,000	76 (19)	80,899 (16)
$50,000–$100,000	194 (48)	241,907 (46)
$100,000–$150,000	110 (27)	150,163 (29)
>$150,000	22 (5)	48,240 (9)
Education—number (%)
Low	168 (42)	182,072 (35)
Medium	123 (31)	165,132 (32)
Long	98 (24)	149,324 (29)
No information available	10 (2)	13,333 (3)
Comorbidity^b—number (%)
Teratogenic infectious diseases^c	1^a (0.3)	133 (0.0)
Folate deficiency	0 (0)	39 (0.0)
Myasthenia gravis	0 (0)	38 (0.0)
Virilizing tumors	0 (0)	84 (0.0)
Diabetes Mellitus	4 (1)	6258 (1)
Alcoholism	0 (0)	111 (0.0)
Amniocentesis	1^a (0.3)	5381 (1.0)
Sjogren’s syndrome	0 (0)	38 (0.0)
HIV/AIDS	0 (0)	60 (0.0)
Pneumocystis carinii pneumonia	0 (0)	2 (0.0)
Previous organ transplantation	1^a (0.0)	49 (0.0)
Use of folic acid—number (%)	9 (2)	4296 (1)

^aNone had offspring with a congenital malformation. ^bAll information on comorbidity were based on diagnoses from the National Hospital Register. ^cSyphilis, toxoplasmosis, rubella virus, varicella virus, parvovirus B-19, cytomegalovirus, herpes simplex viruses 1 and 2, and Venezuelan equine encephalitis virus.