Clindamycin
MedicationAntibiotic
Research strength: 3 / 5
MotherToBaby reports that studies of oral or vaginal clindamycin for vaginal infections did not find higher miscarriage risk, and available oral or vaginal studies have not shown more birth defects. Muanda et al. reported a first-trimester association with major malformations, but this observational result does not prove cause; DailyMed says use during pregnancy only if clearly needed and notes that adequate controlled first-trimester studies are lacking. DailyMed's boxed warning states: "Clostridioides difficile infection (CDI) has been reported with use of nearly all antibacterial agents, including clindamycin HCl and may range in severity from mild diarrhea to fatal colitis." "Because clindamycin HCl therapy has been associated with severe colitis which may end fatally, it should be reserved for serious infections where less toxic antimicrobial agents are inappropriate, as described in the INDICATIONS AND USAGE section." "It should not be used in patients with nonbacterial infections such as most upper respiratory tract infections." Ask your provider about your situation.
Last reviewed: 2026-10-16
Research strength: 3 / 5
MotherToBaby reports no higher chance of birth defects, low birth weight, or preterm delivery with studied oral or vaginal use; DailyMed reports no increased congenital abnormalities with systemic use in the second and third trimesters. For preventing preterm birth, Ugwumadu and Lamont found benefit in selected BV groups; later reviews were mixed, with Yefet reporting benefit in high-risk women while Klebanoff and Wu found no overall effect; CDC recommends treating symptomatic BV but not routine screening to prevent preterm birth, and DailyMed says use during pregnancy only if clearly needed. DailyMed's boxed warning states: "Clostridioides difficile infection (CDI) has been reported with use of nearly all antibacterial agents, including clindamycin HCl and may range in severity from mild diarrhea to fatal colitis." "Because clindamycin HCl therapy has been associated with severe colitis which may end fatally, it should be reserved for serious infections where less toxic antimicrobial agents are inappropriate, as described in the INDICATIONS AND USAGE section." "It should not be used in patients with nonbacterial infections such as most upper respiratory tract infections." Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: ClindamycinTeratology service
- DailyMed: Clindamycin Hydrochloride capsules, USPDrug company label
- CDC: Bacterial VaginosisUS government
- Ugwumadu et al. 2003US government
- Lamont et al. 2011US government
- Klebanoff et al. 2023US government
- Yefet et al. 2025US government
- Wu et al. 2025US government
- Nachum et al. 2026US government
Research strength: 3 / 5
MotherToBaby reports that studied oral or vaginal use did not increase preterm delivery or low birth weight; DailyMed reports no increased congenital abnormalities with systemic use in the second and third trimesters. Recent labor studies found mixed neonatal outcomes with clindamycin prophylaxis for GBS or prolonged membrane rupture; the observational findings do not establish cause, and the label says to use clindamycin during pregnancy only if clearly needed. DailyMed's boxed warning states: "Clostridioides difficile infection (CDI) has been reported with use of nearly all antibacterial agents, including clindamycin HCl and may range in severity from mild diarrhea to fatal colitis." "Because clindamycin HCl therapy has been associated with severe colitis which may end fatally, it should be reserved for serious infections where less toxic antimicrobial agents are inappropriate, as described in the INDICATIONS AND USAGE section." "It should not be used in patients with nonbacterial infections such as most upper respiratory tract infections." Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: ClindamycinTeratology service
- DailyMed: Clindamycin Hydrochloride capsules, USPDrug company label
- ACOG Committee Opinion 797: Prevention of Group B Streptococcal Early-Onset Disease in NewbornsProfessional society
- Abu Shqara et al. 2025US government
- Abu Shqara et al. 2025US government
- Lemonnier et al. 2026US government
Clindamycin — Breastfeeding
Research strength: 2 / 5
MotherToBaby reports that a small amount enters milk and side effects are unlikely for most infants; LactMed says oral or IV use is not a reason to stop breastfeeding, though another medicine may be preferred, and advises watching for gut effects. BfN reports one case of antibiotic-associated colitis in a breastfed infant; LactMed describes bloody stools in a 5-day-old during maternal clindamycin and gentamicin, so the role of clindamycin in milk is unclear. DailyMed's boxed warning states: "Clostridioides difficile infection (CDI) has been reported with use of nearly all antibacterial agents, including clindamycin HCl and may range in severity from mild diarrhea to fatal colitis." "Because clindamycin HCl therapy has been associated with severe colitis which may end fatally, it should be reserved for serious infections where less toxic antimicrobial agents are inappropriate, as described in the INDICATIONS AND USAGE section." "It should not be used in patients with nonbacterial infections such as most upper respiratory tract infections." Ask your provider about your situation.
Last reviewed: 2026-10-16
Sources
- MotherToBaby: ClindamycinTeratology service
- LactMed: ClindamycinUS government
- The Breastfeeding Network: Antibiotics and BreastfeedingBreastfeeding charity
- DailyMed: Clindamycin Hydrochloride capsules, USPDrug company label
Pregnancy
MotherToBaby reports no increased chance of miscarriage in studies of pregnant women treated for vaginal bacterial infections with oral or vaginal clindamycin, and it says some studies found a lower chance of late miscarriage, possibly by treating the infection. Ugwumadu et al. (2003) randomized 494 women at 12-22 weeks with asymptomatic BV or abnormal vaginal flora to oral clindamycin or placebo; 485 had complete outcome data. The combined outcome of late miscarriage or spontaneous preterm birth occurred in 13/244 clindamycin recipients and 38/241 placebo recipients. This trial tested early second-trimester treatment of abnormal vaginal flora or BV, not clindamycin use for all infections or miscarriage at every stage. Muanda et al. (2017) studied 139,938 liveborn singleton pregnancies in Quebec and reported an association between first-trimester clindamycin exposure and major congenital malformations (adjusted OR 1.34, 95% CI 1.02-1.77; 60 exposed cases), musculoskeletal malformations (adjusted OR 1.67, 95% CI 1.12-2.48; 29 cases), and ventricular or atrial septal defects (adjusted OR 1.81, 95% CI 1.04-3.16; 13 cases). This observational association does not prove that clindamycin caused the malformations. MotherToBaby says available studies have not shown increased birth-defect risk with oral or intravaginal use. DailyMed states that first-trimester use is only if clearly needed because adequate controlled studies are lacking; it also states that systemic use in the second and third trimesters was not associated with increased congenital abnormalities. CDC recommends treatment for symptomatic BV during pregnancy, but not routine screening of asymptomatic pregnant women to prevent preterm birth. Evidence about BV treatment to prevent preterm birth differs by risk group and review method: Lamont et al. (2011) included five trials and 2,346 women with abnormal vaginal flora treated before 22 weeks and reported lower late miscarriage and preterm birth before 37 weeks; Klebanoff et al. (2023) included 23 trials and 11,979 participants and found no reduction in preterm delivery after imputing missing study data for clindamycin (OR 0.90, 95% CI 0.72-1.12); Yefet et al. (2025) included seven trials and 738 high-risk women and reported a lower pooled preterm-delivery risk (RR 0.65, 95% CI 0.44-0.98); Wu et al. (2025) included 24 BV-treatment RCTs and found no overall reduction in preterm delivery (RR 1.00, 95% CI 0.80-1.24). Nachum et al. (2026) compared oral clindamycin with oral metronidazole in high-risk pregnancies; 82 metronidazole and 84 clindamycin participants were analyzed, with no significant difference in preterm delivery or late miscarriage. These studies test BV treatment or active-comparator regimens, not a general drug effect. Late-pregnancy studies concern intrapartum prophylaxis rather than routine clindamycin treatment: Abu Shqara et al. (2025) compared 78 clindamycin with 1,833 ampicillin patients with GBS at term and reported greater maternal infectious morbidity but comparable neonatal outcomes; a separate prolonged-membrane-rupture cohort compared 89 clindamycin with 1,418 ampicillin patients and reported greater maternal and neonatal morbidity in the clindamycin group. Both are retrospective and have small clindamycin groups. Lemonnier et al. (2026) found clindamycin resistance in 30 of 138 GBS isolates from beta-lactam-allergic pregnant patients, with no clear increase in neonatal early-onset disease with inappropriate prophylaxis. These results concern effectiveness, resistance, and confounding in labor, not proof of fetal harm from other clindamycin use.
Breastfeeding
MotherToBaby says only a small amount of clindamycin passes into milk after oral or intravenous use and that side effects are unlikely for most infants, while noting that dedicated breastfeeding studies are lacking. LactMed's February 2025 review summarizes small maternal milk-sampling reports and states that published infant blood-level data were not found. LactMed and DailyMed say oral or intravenous clindamycin is not a reason to discontinue breastfeeding, although another medicine may be preferred; they describe possible infant gut effects such as diarrhea, thrush, diaper rash, or rarely blood in stool. LactMed describes a 5-day-old with bloody stools during maternal clindamycin and gentamicin treatment; the case included more than one antibiotic exposure and does not establish that clindamycin in milk caused the symptoms. BfN also reports one case of antibiotic-associated colitis in a breastfed infant and mentions observation for blood in stools. LactMed says vaginal application is unlikely to cause infant side effects, although some of the vaginal dose is absorbed. Overall, the published breastfeeding evidence consists of small milk-sampling reports and individual case reports, and infant blood levels have not been reported in LactMed.
Clindamycin is a lincosamide antibiotic. MotherToBaby describes oral, topical, vaginal, and intravenous forms. The current DailyMed capsule label states that each capsule contains clindamycin hydrochloride equivalent to 150 mg or 300 mg of clindamycin. It lists corn starch, FD&C blue no. 1, gelatin, lactose, magnesium stearate, talc, and titanium dioxide in the 150 mg capsule; the 300 mg capsule contains the same listed ingredients except FD&C yellow no. 5 is not included in the 300 mg list. The label describes clindamycin as a semisynthetic antibacterial drug derived from lincomycin and says it inhibits bacterial protein synthesis by binding to the 50S ribosomal subunit.
What was tested
Pregnancy evidence includes observational exposure studies, trials treating BV or abnormal vaginal flora, and reviews of those trials. Ugwumadu et al. (2003) randomized 494 women at 12-22 weeks and analyzed 485; the combined late-miscarriage/preterm-birth outcome was 13/244 with clindamycin and 38/241 with placebo. Muanda et al. (2017) examined first-trimester antibiotic exposure in a Quebec cohort of 139,938 liveborn singleton pregnancies. Lamont et al. (2011) reviewed five clindamycin trials with 2,346 women; Klebanoff et al. (2023) reviewed 23 trials with 11,979 participants; Yefet et al. (2025) reviewed seven trials with 738 high-risk women; Wu et al. (2025) included 24 RCTs; and Nachum et al. (2026) analyzed 166 pregnant participants in an active-comparator trial. The GBS and prolonged-membrane-rupture reports are retrospective intrapartum prophylaxis cohorts: Abu Shqara et al. compared 78 with 1,833 patients in one cohort and 89 with 1,418 in another; Lemonnier et al. studied 138 beta-lactam-allergic GBS carriers. These studies do not isolate clindamycin from indication, resistance, allergy status, or other clinical differences. Breastfeeding evidence consists of small maternal milk-sampling reports and case reports; LactMed found no published infant blood-level data as of its February 2025 revision.
First-trimester congenital-malformation findings
- Source A says
- MotherToBaby says available oral and intravaginal pregnancy studies have not shown an increased chance of birth defects. (MotherToBaby: Clindamycin)
- Source B says
- Muanda et al. reported an association between first-trimester clindamycin exposure and major malformations, including musculoskeletal and septal defects, in a population cohort. (Muanda et al. 2017, population-based cohort study)
- Why they differ
- MotherToBaby summarizes the broader published pregnancy literature. Muanda et al. assessed first-trimester exposure and specific outcomes in an observational cohort. Confounding and the observational design limit causal conclusions.
- What the evidence shows overall
- The cohort association is not proof that clindamycin caused malformations. It is still a relevant signal and should be shown alongside the more reassuring summaries and the label's first-trimester data limitation.
Whether treating BV prevents preterm birth
- Source A says
- Ugwumadu and Lamont reported benefit for early treatment of BV or abnormal vaginal flora, and Yefet reported a lower pooled preterm-delivery risk in high-risk women. (Ugwumadu et al. 2003, randomized controlled trial, Lamont et al. 2011, systematic review and meta-analysis, Yefet et al. 2025, systematic review and meta-analysis)
- Source B says
- Klebanoff found no clindamycin effect after imputing missing trial data; Wu found no overall reduction across BV-treatment trials. Nachum found similar rates with clindamycin and metronidazole, not against no treatment. (Klebanoff et al. 2023, individual participant data meta-analysis, Wu et al. 2025, network meta-analysis, Nachum et al. 2026, randomized active-comparator trial)
- Why they differ
- The studies vary in participant risk, gestational timing, comparator, and methods for handling missing trials. They test treatment of BV or abnormal vaginal flora to prevent preterm birth, not clindamycin's general effects in pregnancy.
- Other sources
- CDC recommends treatment for symptomatic BV in pregnancy but does not recommend routine screening of asymptomatic pregnant women solely to prevent preterm birth. (CDC: Bacterial Vaginosis, STI Treatment Guidelines)
- What the evidence shows overall
- The results do not support saying that clindamycin generally lowers preterm-birth risk. The evidence differs by clinical group and analysis, while treatment of symptomatic BV remains a separate question.
Clindamycin during intrapartum GBS or prolonged-membrane-rupture prophylaxis
- Source A says
- Abu Shqara et al. reported higher maternal infectious morbidity with clindamycin than ampicillin in a GBS-positive term cohort; a separate prolonged-membrane-rupture cohort reported higher maternal and neonatal morbidity in the clindamycin group. (Abu Shqara et al. 2025, GBS intrapartum cohort, Abu Shqara et al. 2025, prolonged membrane rupture cohort)
- Source B says
- The GBS-positive term cohort reported comparable neonatal outcomes, and Lemonnier et al. found no clear increase in neonatal early-onset disease with inappropriate prophylaxis, despite clindamycin resistance in some isolates. (Abu Shqara et al. 2025, GBS intrapartum cohort, Lemonnier et al. 2026, GBS prophylaxis cohort)
- Why they differ
- These retrospective studies involve different GBS status, membrane-rupture circumstances, comparators, and small clindamycin groups. Resistance, reported allergy, and indication may affect outcomes.
- Other sources
- ACOG describes intrapartum antibiotic prophylaxis as prevention for newborn GBS early-onset disease and recommends prophylaxis for positive screening cultures unless a prelabor cesarean occurs with intact membranes. (ACOG Committee Opinion 797: Prevention of Group B Streptococcal Early-Onset Disease in Newborns)
- What the evidence shows overall
- The studies raise a question about the effectiveness of clindamycin prophylaxis in specific labor settings. They do not establish that clindamycin causes neonatal harm or apply to all uses of the medicine.
- CDC recommends treatment for symptomatic BV during pregnancy and says routine screening of asymptomatic pregnant women to prevent preterm birth is not recommended. The CDC regimen list includes clindamycin 2% vaginal cream, one applicator (5 g) at bedtime for 7 days. (CDC: Bacterial Vaginosis)
- LactMed says oral or intravenous clindamycin is not a reason to discontinue breastfeeding, although an alternate medicine may be preferred; it advises watching the infant for diarrhea, thrush, diaper rash, or rarely blood in the stool. (LactMed: Clindamycin)
General research, not specific to pregnancy.
The current clindamycin capsule label warns about Clostridioides difficile infection and acute kidney injury. These effects are not limited to pregnancy.
- DailyMed states that CDI has been reported with nearly all antibacterial agents, including clindamycin, and can range from mild diarrhea to fatal colitis. The label says, "Because clindamycin HCl therapy has been associated with severe colitis which may end fatally, it should be reserved for serious infections where less toxic antimicrobial agents are inappropriate." It also says not to use it for nonbacterial infections such as most upper respiratory tract infections. (DailyMed: Clindamycin Hydrochloride capsules, USP (Greenstone/Mylan))
- DailyMed reports acute kidney injury and says to consider kidney-function monitoring for people with pre-existing kidney problems or those taking other medicines that can affect the kidneys. The label says to discontinue clindamycin if acute kidney injury occurs and no other cause is identified. (DailyMed: Clindamycin Hydrochloride capsules, USP (Greenstone/Mylan))
- MotherToBaby: ClindamycinTeratology serviceSecondaryIndependent check
- LactMed: ClindamycinUS governmentSecondaryPage dated 2025-02-15Independent check
- DailyMed: Clindamycin Hydrochloride capsules, USP (Greenstone/Mylan)Drug company labelTertiaryPage dated 2026-10-09
- CDC: Bacterial Vaginosis, STI Treatment GuidelinesUS governmentSecondaryPage dated 2021-07-22Independent check
- The Breastfeeding Network: Antibiotics and BreastfeedingBreastfeeding charitySecondaryIndependent check
- ACOG Committee Opinion 797: Prevention of Group B Streptococcal Early-Onset Disease in NewbornsProfessional societySecondaryIndependent check
- Ugwumadu et al. 2003, randomized controlled trialUS governmentPrimaryIndependent check
- Muanda et al. 2017, population-based cohort studyUS governmentPrimaryIndependent check
- Lamont et al. 2011, systematic review and meta-analysisUS governmentPrimaryIndependent check
- Klebanoff et al. 2023, individual participant data meta-analysisUS governmentPrimaryIndependent check
- Yefet et al. 2025, systematic review and meta-analysisUS governmentPrimaryIndependent check
- Wu et al. 2025, network meta-analysisUS governmentPrimaryIndependent check
- Nachum et al. 2026, randomized active-comparator trialUS governmentPrimaryIndependent check
- Abu Shqara et al. 2025, GBS intrapartum cohortUS governmentPrimaryIndependent check
- Abu Shqara et al. 2025, prolonged membrane rupture cohortUS governmentPrimaryIndependent check
- Lemonnier et al. 2026, GBS prophylaxis cohortUS governmentPrimaryIndependent check
Last reviewed 2026-10-16
Independent check 2026-10-16
Not yet clinician-reviewed
Ask your provider about your situation.