Diatrizoate

 Risk Factor: D
 Class: DIAGNOSTIC AGENTS

Contents of this page:

Fetal Risk Summary
Breast Feeding Summary
References
Questions and Answers

Fetal Risk Summary

The use of diatrizoate for amniography has been described in several studies (1,2,3,4,5,6,7,8,9 and 10). Except for inadvertent injection of the contrast media into the fetus during amniocentesis, the use of diatrizoate was not thought to result in fetal harm. More recent studies have examined the effect of the drug on fetal thyroid function.

All of the various preparations of diatrizoate contain a high concentration of organically bound iodine. Twenty-eight pregnant women received intra-amniotic injections (50 mL) of diatrizoate for diagnostic indications (11). When compared to nontreated controls, no effect was observed on cord blood levothyroxine (T4) and liothyronine resin uptake values regardless of the time interval between injection and delivery. The authors concluded that the iodine remained organically bound until it was eliminated in 24 days from the amniotic fluid.

In another report, seven patients within 13 days or less of term were injected intra-amniotically with a mixture of ethiodized oil (12 mL) and diatrizoate (30 mL) (12). Thyrotropin (TSH) levels were determined in the cord blood of five newborns and in the serum of all 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: Elevated TSH/normal T4; apathy and jaundice clearing immediately with thyroid therapy (1 infant) Elevated TSH/decreased T4 (1 infant) Elevated TSH/decreased T4 with goiter (1 infant) In contrast to the initial report, the severity of thyroid suppression seemed greater the longer the time interval between injection and delivery. The explanation offered for these different results was the use of the more sensitive TSH serum test and the use of only water-soluble contrast media in the first study.

In summary, diatrizoate may suppress the fetal thyroid when administered by intra-amniotic injection. Appropriate measures should be taken to diagnose and treat neonatal hypothyroidism if amniography with diatrizoate is performed.

Breast Feeding Summary

No data are available. See also Potassium Iodide.

References

1. McLain CR Jr. Amniography studies of the gastrointestinal motility of the human fetus. Am J Obstet Gynecol 1963;86:107987.
2. McLain CR Jr. Amniography, a versatile diagnostic procedure in obstetrics. Obstet Gynecol 1964;23:4550.
3. McLain CR Jr. Amniography for diagnosis and management of fetal death in utero. Obstet Gynecol 1965;26:2336.
4. Ferris EJ, Shapiro JH, Spira J. Roentgenologic aspects of intrauterine transfusion. JAMA 1966;196:1278.
5. Wiltchik SG, Schwarz RH, Emich JP Jr. Amniography for placental localization. Obstet Gynecol 1966;28:6415.
6. Misenhimer HR. Fetal hemorrhage associated with amniocentesis. Am J Obstet Gynecol 1966;94:11335.
7. Blumberg ML, Wohl GT, Wiltchik S, Schwarz R, Emich JP. Placental localization by amniography. AJR 1967;100:68897.
8. Berner HW Jr. Amniography, an accurate way to localize the placenta. Obstet Gynecol 1967;29:2006.
9. Creasman WT, Lawrence RA, Thiede HA. Fetal complications of amniocentesis. JAMA 1968;204:94952.
10. Bottorff MK, Fish SA. Amniography. S Med J 1971;64:12036.
11. Morrison JC, Boyd M, Friedman BI, Bucovaz ET, Whybrew WD, Koury DN, Wiser WL, Fish SA. The effects of Renografin-60 on the fetal thyroid. Obstet Gynecol 1973;42:99103.
12. Rodesch F, Camus M, Ermans AM, Dodion J, Delange F. Adverse effect of amniofetography on fetal thyroid function. Am J Obstet Gynecol 1976;126:7236.
    
    

Questions and Answers

PartA: .378m solution is prepared by dissolving 38.4g of sodium diatrizoate in 1.60x10^2 mL of water at 31.2ºC, (The density of water at this temp is .995 g/mL) What is the molar mass of sodium diatrizoate?

Part B: What is the vapor pressure of the solution if the vapor pressure of pure water at this temp is 34.1?

A
The amount of substance dissolved equals molarity times volume:

N_solute = c_solute · V_solution
= 0.378mol/L · 0.160L
= 0.06048mol

The molar mass of the solute is:
M = m_solute / N_solute
= 38.4g / 0.06048mol
= 634.92 g/mol


B
The amount of water in the solution
N_H2O = m_H2O / M_H2O
= ρ_H2O · V_H2O / M_H2O
= 995g/L · 0.160L / 18g/mol
= 8.84444mol

The mole fraction of water in the solution
x_H2O = N_H20 / (2·N_solute + N_H2O) = 0.9932
(you have to multiply by two, because the solute dissociate into two parts)

The vapor pressure of the solute is negligible. Hence the vapor pressure of the solution is equal to water vapor pressure, which is according to Raoult's law equal to mole fraction times pure water vapor pressure:
p = p_H2O
= x_H2O · p°_H2O
= .9932 · 34.1torr
= 33.87torr