Animal studies are not available for the combination product. There are no controlled data in human pregnancy.

Chlorpheniramine: A monitoring study of 50, 282 mother/child pairs (1070 first trimester exposures, 3931 any time pregnancy exposures) did not suggest a link to categories of major or minor malformations, however possible individual associated malformations were found (7 cases polydactyly in 272 blacks, 13 gastrointestinal defect cases, 7 cases of eye and ear defects, 22 inguinal hernias, 8 hydrocephaly cases, 16 congenital hip malformations, and 6 cases of female genitalia malformations). A 1971 study in which chlorpheniramine was the sixth most used antihistamine found fewer malformations in infants exposed to antihistamines in the first trimester. Antihistamine exposure during the last 2 weeks of pregnancy may be associated with retrolental fibroplasia in premature infants.

Phenylephrine: A monitoring study including 1249 mother-child pairs that had first trimester phenylephrine exposure showed an increase in malformation, with association greater with minor defects than major defects (8 eye and ear defects, 6 syndactyly, 4 preauricular skin tags, and 3 clubfoot cases); 4149 any time pregnancy exposures were associated with 15 congenital dislocation of the hip, 6 umbilical hernia, and 4 other musculoskeletal defects. Placental transfer is likely with phenylephrine's low molecular weight (about 167).

AU TGA pregnancy category B2: Drugs which have been taken by only a limited number of pregnant women and women of childbearing age, without an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals are inadequate or may be lacking, but available data show no evidence of an increased occurrence of fetal damage.

US FDA pregnancy category Not Assigned: The US FDA has amended the pregnancy labeling rule for prescription drug products to require labeling that includes a summary of risk, a discussion of the data supporting that summary, and relevant information to help health care providers make prescribing decisions and counsel women about the use of drugs during pregnancy. Pregnancy categories A, B, C, D, and X are being phased out.

Safety has not been established during pregnancy

AU TGA pregnancy category: B2
US FDA pregnancy category: Not assigned

Comments:
-Phenylephrine is a sympathomimetic used in emergencies to treat hypotension and alleviate eye and ear allergic symptoms.
-Phenylephrine could cause constriction in uterine vessels (that are normally maximally dilated during pregnancy), reducing uterine blood flow, potentially causing fetal hypoxia.
-Phenylephrine may interact with oxytocic or ergot derivatives to cause persistent maternal hypertension; cerebral vessel rupture is possible.
-Sympathomimetic amines are teratogenic in some animal models, but is not suspected to cause human teratogenicity.

See references

Safety has not been established.

Excreted into human milk: Data not available (chlorpheniramine, phenylephrine)
Excreted into animal milk: Data not available (chlorpheniramine, phenylephrine)

Comments:
-Phenylephrine oral bioavailability is about 40%, making it unlikely an infant would receive large doses from breast milk.
-Phenylephrine may decrease milk production.
-Products with high alcohol content should be avoided during while breastfeeding.
-Occasional small chlorpheniramine doses during breastfeeding may be acceptable, but large doses or prolonged use may have adverse effects on the infant or decrease milk production, particularly in combination with pseudoephedrine or before lactation is established.

See references