CHLORAL HYDRATE

Fetal Risk Summary

No reports linking the use of chloral hydrate with congenital defects have been located. The drug has been given in labor and demonstrated to be in cord blood at concentrations similar to maternal levels (1). Sedative effects on the neonate have not been studied.

The Collaborative Perinatal Project recorded 71 1st trimester exposures to chloral hydrate (2, pp. 336–44). From this group, 8 infants with congenital defects were observed (standardized relative risk [SRR] 1.68). When only malformations with uniform rates by hospital were examined, the SRR was 2.19. Neither of these relative risks reached statistical significance. Moreover, when chloral hydrate was combined with all tranquilizers and nonbarbiturate sedatives, no association with congenital malformations was found (SRR 1.13; 95% CI 0.88–1.44). For use anytime during pregnancy, 358 exposures to chloral hydrate were discovered (2, p. 438). The 9 infants with anomalies yielded a SRR of 0.98 (95% CI 0.45–1.84).

Breast Feeding Summary

Chloral hydrate and its active metabolite are excreted into breast milk. Peak concentrations of about 8 µmg/mL were obtained about 45 minutes after a 1.3-g rectal dose (3). Only trace amounts are detectable after 10 hours.

Mild drowsiness was observed in the nursing infant of a mother taking 1300 mg of dichloralphenazone every evening (4). The mother was also consuming chlorpromazine 100 mg three times daily. Dichloralphenazone is metabolized to trichloroethanol, the same active metabolite of chloral hydrate. Milk levels of trichloroethanol were 60%–80% of the maternal serum. Infant growth and development remained normal during the exposure and at follow-up 3 months after the drug was stopped. The American Academy of Pediatrics considers the drug to be compatible with breast feeding (5).

References

1. Bernstine JB, Meyer AE, Hayman HB. Maternal and fetal blood estimation following the administration of chloral hydrate during labor. J Obstet Gynecol Br Emp 1954;61:683–5.
2. Heinonen OP, Slone D, Shapiro S. Birth Defects and Drugs in Pregnancy. Littleton, MA:Publishing Sciences Group, 1977.
3. Bernstine JB, Meyer AE, Bernstine RL. Maternal blood and breast milk estimation following the administration of chloral hydrate during the puerperium. J Obstet Gynecol Br Emp 1956;63:228–31.
4. Lacey JH. Dichloralphenazone and breast milk. Br Med J 1971;4:684.
5. Committee on Drugs, American Academy of Pediatrics. The transfer of drugs and other chemicals into human milk. Pediatrics 1994;93:137–50.