Pregnant women should be apprised of the potential harm to the fetus.
-According to some authorities: As a precaution, use should be avoided.

US FDA pregnancy category: Not assigned.

Risk summary: May cause fetal harm (based on animal studies with vaborbactam); insufficient human data available on use of this drug in pregnant women to inform a drug-related risk.

Animal studies with meropenem have failed to reveal evidence of fetal harm, although slight changes in fetal body weight were noted. Animal studies with vaborbactam have revealed evidence of teratogenicity in rabbits but failed to reveal evidence of embryofetal toxicity in rats; interventricular septal defects, a fused right lung lobe, and supernumerary lung lobes were seen in offspring of pregnant rabbits given IV vaborbactam (30-minute infusion) during organogenesis at doses about equal to or above the maximum recommended human dose (MRHD) based on comparison of plasma AUC. The no-observed-adverse-effect-level for vaborbactam in rabbits was considered 0.3 times the MRHD based on comparison of plasma AUC exposure and 6 times the MRHD based on comparison of Cmax; clinical significance of the malformations has not been established. There are no controlled data in human pregnancy.

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.

See references

MEROPENEM:
On day 6 postpartum, a mother started meropenem 1 g IV every 8 hours for 7 days; her newborn was exclusively breastfed. From day 6 to day 9 postpartum, 5 samples of hindmilk were collected over 37 hours; over this period, the highest, lowest, and average meropenem levels in breast milk were 644, 246, and 480 mcg/L, respectively. Estimated average and maximum infant intake were 71 mcg/kg/day (0.13% of weight-adjusted maternal dose) and 97 mcg/kg/day (0.18% of weight-adjusted maternal dose), respectively. When asked later, the mother stated her infant had no oral thrush, watery diarrhea, or diaper dermatitis requiring antifungal therapy during the month after her meropenem therapy.

An infant was breastfed (extent not provided) until the 4th month postpartum. At 2 months of age, his mother was given tobramycin and meropenem (dose not provided) for 2 weeks for a cystic fibrosis exacerbation. The infant's stool pattern did not change during maternal therapy and he had normal renal function at 6 months of age.

Benefit should outweigh risk.
-According to some authorities: Breastfeeding should be discontinued before starting therapy.

Excreted into human milk: Yes (meropenem); Unknown (vaborbactam)
Excreted into animal milk: Data not available (vaborbactam)

Comments:
-Developmental and health benefits of breastfeeding should be considered as well as the mother's clinical need for this drug.
-The effects in the nursing infant are unknown; potential side effects in the breastfed child due to this drug or the mother's underlying condition should be considered.
-While no data are available on the use of meropenem during breastfeeding, milk levels appear low and beta-lactams are generally not expected to cause harmful effects in nursing infants.
-Disruption of infant's gastrointestinal flora (resulting in diarrhea or thrush) reported occasionally with beta-lactams; such effects have not been adequately evaluated.
-Vaborbactam has not been studied in breastfeeding mothers; similar concerns as with meropenem alone are expected with this combination drug.

See references