A woman has, in the eighth week of pregnancy, been prescribed a total number of 12 tablets of Chole

Fråga: A woman has, in the eighth week of pregnancy, been prescribed a total number of 12 tablets of Cholebrin (iocetamic acid) divided in two days due to a cholecystografi. Is there a risk for the fetus?

Sammanfattning: We have not found any specific documentation concerning risks with iocetamic acid during pregnancy. The thyroid gland begins to function in the 10th to the 12th week in human embryos. In the present case the risk for the fetus seems remote. To fully elucidate the function of this child´s thyroid gland s-TSH, free s-T3 and free s-T4 could be analysed in cord blood when the child is born.

Svar: A thorough literature search and personal communication with the manufacturer representative (1) have not revealed any documentation concerning the use of iocetamic acid during pregnancy. There is no report of fetal damage in SWEDIS (2) or the WHO side effect register during treatment with iocetamic acid.

Iocetamic acid contains a high concentration of organically bound iodine, which is also the case for diatrizoate. In one report, concerning diatrizoate, including 28 pregnant women who received intra-amniotic injections (50 mL) of diatrizoate for diagnostic indications no effect was observed on cord blood levothyroxine (T4) and liothyronine resin uptake values compared with nontreated controls regardless of the time interval between injection and delivery (3).

In another report, seven patients within 13 days or less of term were injected intra-amniotically with a mixture of iodised oil (12 mL) and diatrizoate (30 mL). Thyrotropin (TSH) levels were determined in the cord blood of five new-borns and in serum of seven infants on the 5th day of life. TSH was markedly elevated in three of five cord samples and six of seven neonatal samples. Three of the infants had signs and symptoms of hypothyroidism. It is known that occasional high doses of iodine may cause transient laboratory signs of hypothyroidism (4,6).

In the present case the fetus was exposed in the sixth embryology week. The development of the thyroid gland starts late in the fourth week. Studies on the ability of the embryonic thyroid to incorporate iodine into thyroid hormones and to secrete these hormones into the circulation show that this gland begins to function in the 10th to the 12th week in human embryos (5). Therefore the risk for this fetus seems remote. In Sweden all new-borns are tested for neonatal hypothyroidism within 72 hours after delivery. If treatment is started within ten days after delivery these children develop fully normally (4,6). In the present case s-TSH, free s-T3 and free s-T4 could be analysed in cord blood when the child is born (6). 1 Jan-Olov Wickgren, manufacturer representative, Nycomed 2 SWEDIS (The Swedish Drug Information System) 3 Briggs GB, Freeman RK, Yaffe SJ. Drugs in pregnancy and lactation. 5th ed. Baltimore: Williams & Wilkins; 1998. p. 312D 4 Ulrica von Döbeln, senoir consultant, Ass. Professor, Laboratory of Metabolic diseases, Huddinge University Hospital 5 Larsen WJ. Human embryology. New York: Churchill Livingstone Inc; 1993. p. 336 6 Annika Janson, MD, Department of Pediatrics, Huddinge University Hospital