Gastroenterology  1998 Jan;114(1):23-8 

The safety of mesalamine in human pregnancy: a prospective controlled cohort

study.

Diav-Citrin O, Park YH, Veerasuntharam G, Polachek H, Bologa M, Pastuszak A,

Koren G.

Motherisk Program, Department of Pediatrics, Hospital for Sick Children,

Toronto, Ontario, Canada.

BACKGROUND & AIMS: Mesalamine is a first-line drug in the treatment of

inflammatory bowel disease. Information regarding human pregnancy experience

with mesalamine has been scarce and uncontrolled despite its frequent use in

women of childbearing age. The aim of this study was to examine the fetal safety

of mesalamine. METHODS: The Motherisk Program prospectively enrolled and

followed up 165 women exposed to mesalamine during pregnancy, 146 of whom had

first trimester exposure. Pregnancy outcome was compared with that of a matched

control group, who were counseled for nonteratogenic exposure. RESULTS: There

was no increase in major malformations (1 of 127 [0.8%] for mesalamine vs. 5 of

131 [3.8%] for nonteratogenic controls; P = 0.23). There was an increase in the

rate of preterm deliveries (13.0% for mesalamine vs. 4.7% for nonteratogenic

controls; P = 0.02), a decrease in the mean maternal weight gain during

pregnancy (13.1 +/- 6.3 kg for mesalamine vs. 15.6 +/- 6.0 kg for nonteratogenic

controls; P = 0.0002), and a decrease in the mean birth weight (3253 +/- 546 g

for mesalamine vs. 3461 +/- 542 g for nonteratogenic controls; P = 0.0005).

There were no significant differences in the maternal obstetric history, rates

of live births, miscarriages, pregnancy terminations, ectopic pregnancies,

delivery method, or fetal distress between the groups. CONCLUSIONS: This study

suggests that mesalamine does not represent a major teratogenic risk in humans

when used in the recommended doses.