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Ampicillin / sulbactam Pregnancy and Breastfeeding Warnings

Medically reviewed by Last updated on Oct 27, 2022.

Ampicillin / sulbactam is also known as: Unasyn

Ampicillin / sulbactam Pregnancy Warnings

This drug should be used during pregnancy only if clearly needed.

US FDA pregnancy category: B

Animal studies have failed to reveal evidence of fetal harm. There are no controlled data in human pregnancy.

US FDA pregnancy category B: Animal reproduction studies have failed to demonstrate a risk to the fetus and there are no adequate and well-controlled studies in pregnant women.

See references

Ampicillin / sulbactam Breastfeeding Warnings

Candidiasis and diarrhea have been reported in an infant exposed to ampicillin via breast milk; causality unknown.

Milk levels were 0.3 to 0.9 mg/L in 3 mothers who received ampicillin 2 g IM daily and 0.4 to 0.9 mg/L in 3 mothers who received 4 g IM daily. Peak milk levels were observed 3 hours postdose. It was estimated that the breastfed infant received 0.08 to 0.2 mg ampicillin daily with such doses.

Milk ampicillin levels averaged 0.11, 0.21, 0.17, 0.27, and 0.26 mg/L at 30 minutes, 1 hour, 2 hours, 4 hours, and 6 hours after the dose, respectively, in 15 women receiving ampicillin 500 mg IM 4 times a day.

Two hours after a single dose of ampicillin 2 g IV, milk levels averaged 1.1 mg/L.

Milk was collected at random times after doses of sulbactam 0.5 or 1 g infused IV over 20 minutes. Milk levels averaged 0.52 mg/L during the first 8 hours postdose and the highest level was 2.8 mg/L; milk levels varied slightly over that period and there was little difference between the 2 doses. Levels obtained 10.5 to 20.5 hours postdose were 0.12 to 1.2 mg/L.

In a study, postpartum women with endometritis received ampicillin 1 g plus sulbactam 0.5 g or ampicillin 2 g plus sulbactam 1 g infused IV over 20 minutes. Ampicillin milk levels averaged 1.7 mg/L and the highest level was 3 mg/L. Sulbactam milk levels averaged 0.58 mg/L and the highest level was 2.8 mg/L.

Five nursing mothers reported taking oral ampicillin (dose not provided) in a prospective follow-up study. One mother reported diarrhea in her infant. Neither rash nor candidiasis was observed in exposed infants.

During a small and controlled prospective study, mothers monitored their infants for signs of side effects (furring of the tongue, feeding difficulties, changes in stool frequency and consistency, diaper rash, skin rash), weight change, and jaundice. These parameters were not statistically different when infants of control mothers and of mothers taking oral ampicillin were compared.

Use is considered acceptable; caution is recommended.

Excreted into human milk: Yes (both components in small amounts)

-Low levels in milk are not expected to cause harmful effects in the nursing infant.
-Ampicillin is considered compatible with breastfeeding by the WHO.
-Sulbactam is considered compatible with breastfeeding by the American Academy of Pediatrics.

See references

References for pregnancy information

  1. "Product Information. Unasyn (ampicillin-sulbactam)." Roerig Division (2002):
  2. Lovett SM, Weiss JD, Diogo MJ, Williams PT, Garite TJ "A prospective, double-blind, randomized, controlled clinical trial of ampicillin-sulbactam for preterm premature rupture of membranes in women receiving antenatal corticosteroid therapy." Am J Obstet Gynecol 176 (1997): 1030-8

References for breastfeeding information

  1. Campbell AC, McElnay JC, Passmore CM "The excretion of ampicillin in breast milk and its effect on the suckling infant." Br J Clin Pharmacol 31 (1991): p230
  2. Matheson I, Samseth M, Sande HA "Ampicillin in breast milk during puerperal infections." Eur J Clin Pharmacol 34 (1988): 657-9
  3. Foulds G, Miller RD, Knirsch AK, Thrupp LD "Sulbactam kinetics and excretion into breast milk in postpartum women." Clin Pharmacol Ther 38 (1985): 692-6
  4. "Product Information. Unasyn (ampicillin-sulbactam)." Roerig Division (2002):
  5. American Academy of Pediatrics Committee on Drugs "The transfer of drugs and other chemicals into human milk" Pediatrics 108 (2001): 776-789
  6. United States National Library of Medicine "Toxnet. Toxicology Data Network." (2013):
  7. Department of Adolescent and Child Health and Development. UNICEF. World Health Organization "Breastfeeding and maternal medication: recommendations for drugs in the eleventh Who model list of essential drugs." (2014):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.