Recommendations for the Use of Antiretroviral Drugs in Pregnant Women with HIV Infection and Interventions to Reduce Perinatal HIV Transmission in the United States

The information in the brief version is excerpted directly from the full-text guidelines. The brief version is a compilation of the tables and boxed recommendations.

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Nucleoside and Nucleotide Analogue Reverse Transcriptase Inhibitors

Lamivudine (Epivir, 3TC)

Last Updated: December 24, 2019; Last Reviewed: December 24, 2019

Animal Studies

Lamivudine (3TC) was found to have weak mutagenic activity in one in vitro assay, but there was no evidence of in vivo genotoxicity in rats at 35 times to 45 times the exposure observed in humans who received the standard dose. Long-term animal studies have shown no evidence of carcinogenicity at exposures that were 10 times (in mice) and 58 times (in rats) the exposure seen in humans who received the standard dose.1

In rats that received 3TC in doses up to 4,000 mg/kg per day, which produced plasma levels 47 times to 70 times those seen in humans who received the standard dose, there was no evidence of impaired fertility and no effects on the offspring’s survival, growth, or development up to the time of weaning.1

Teratogenicity/Adverse Pregnancy Outcomes
There is no evidence of 3TC-induced teratogenicity in rats and rabbits at plasma concentrations of 3TC that are 35 times those seen in human plasma. Early embryo lethality was seen in rabbits at exposures that were similar to human therapeutic exposure, but no early embryo lethality was seen in rats with 3TC exposures that were 35 times the exposure observed in humans who received the standard dose.1

Placental and Breast Milk Passage 
In studies of pregnant rats, 3TC was transferred to the fetus through the placenta.1

Human Studies in Pregnancy

Two separate studies have reported that pregnancy does not significantly affect 3TC pharmacokinetic parameters.2,3 This was confirmed in an analysis of 114 pregnant women, 123 women in labor, and 47 nonpregnant women, in which all participants received standard once-daily or twice-daily 3TC doses.4 Pregnant women had a 22% higher apparent clearance rate than nonpregnant and postpartum women, but this increase did not lead to subtherapeutic exposure. Although the level of 3TC exposure in pregnant women was lower than the exposure in nonpregnant and parturient women, it was relatively close to levels that were reported previously for nonpregnant adults.4 Thus, no dose adjustment is necessary for 3TC during pregnancy.

Placental and Breast Milk Passage 
3TC readily crosses the placenta in humans, achieving cord blood concentrations comparable to maternal plasma concentrations.3 In a study of 123 mother/infant pairs, the placental transfer, expressed as the fetal-to-maternal area under the curve (AUC) ratio, was 0.86. The 3TC amniotic fluid accumulation, expressed as the amniotic fluid-to-fetal AUC ratio, was 2.9.4 Other studies have also noted that urinary excretion of 3TC by the fetus can cause 3TC to accumulate in the amniotic fluid.2

3TC is excreted into human breast milk. In a study in Kenya of 67 nursing mothers who received a combination regimen of zidovudine, 3TC, and nevirapine, the median breast milk 3TC concentration was 1,214 ng/mL and the median ratio of 3TC concentration in breast milk to the concentration in plasma was 2.56.5 In infants who were exposed to 3TC only via breast milk, the median plasma 3TC concentration was 23 ng/mL (inhibitory concentration 50% [IC50] of 3TC against wild-type HIV = 0.6–21 ng/mL). In a separate study of breastfeeding women in Malawi who were receiving 3TC in combination with tenofovir disoproxil fumarate and efavirenz, concentrations of 3TC in breast milk were higher than those in maternal plasma at 1 month (3.29-fold higher) and 12 months (2.35-fold higher) after delivery. Infant plasma levels at ages 6 and 12 months, on the other hand, revealed median 3TC concentrations of only 2.5 ng/mL (with an interquartile range [IQR] of 2.5–7.6) and 0 ng/mL (with an IQR of 0–2.5), respectively.6

Teratogenicity/Adverse Pregnancy Outcomes
In a large French cohort, 3TC exposure during the first trimester was associated with an increased risk of overall birth defects (adjusted odds ratio = 1.37; 95% confidence interval [CI], 1.06–1.73), but not of a defect in any specific organ system or of a specific birth defect.7 In the Antiretroviral Pregnancy Registry, sufficient numbers of first-trimester exposures to 3TC have been monitored to detect at least a 1.5-fold increase in risk of overall birth defects and a two-fold increase in the risk of cardiovascular and genitourinary defects (the most common classes of birth defects in the general population). No such increase in the risk of birth defects has been observed with 3TC. Among the cases of first-trimester 3TC exposure that have been reported to the Antiretroviral Pregnancy Registry, the prevalence of birth defects was 3.0% (156 of 5,132 births; 95% CI, 2.6% to 3.5%) compared with a 2.7% total prevalence in the U.S. population, based on Centers for Disease Control and Prevention surveillance.8

An analysis of Antiretroviral Pregnancy Registry data demonstrated that there is a lower risk of spontaneous abortions, induced abortions, and preterm births with use of 3TC-containing regimens than with use of antiretroviral regimens that do not include 3TC.9

Other Safety Information
In a large U.S. cohort study of infants without HIV born to women with HIV, 3TC exposure during pregnancy was not associated with increased risk of adverse infant outcomes in any of the growth, hearing, language, neurology, neurodevelopment, metabolic, hematologic/clinical chemistry, and blood lactate domains assessed.10

Excerpt from Table 8

Note: When using FDCs, refer to other sections in Appendix B and Table 8 for information about the dosing and safety of individual drug components of the FDC during pregnancy.

Excerpt from Table 8
Generic Name
Trade Name
Formulation Dosing Recommendationsa Use in Pregnancy







Symfi Lo




Generic products are available for some formulations
3TC (Epivir)d
  • 150 mg
  • 300 mg
Oral Solution:
  • 10 mg/mL
3TC/TDF (Cimduo):
  • 3TC 300 mg/TDF 300 mg tablet
3TC/ZDV (Combivir):d
  • 3TC 150 mg/ZDV 300 mg tablet
3TC/DOR/TDF (Delstrigo):
  • 3TC 300 mg/DTG 50 mg tablet
3TC/DTG (Dovato):
  • 3TC 300 mg/DTG 50 mg tablet
3TC/ABC (Epzicom):d
  • 3TC 300 mg/ABC 600 mg tablet
3TC/EFV/TDF (Symfi):
  • 3TC 300 mg/EFV 600 mg/TDF 300 mg tablet
3TC/EFV/TDF (Symfi Lo):
  • 3TC 300 mg/EFV 400 mg/TDF 300 mg tablet
3TC/TDF (Temixys):
  • 3TC 300 mg/TDF 300 mg tablet
3TC/ABC/DTG (Triumeq):
  • 3TC 300 mg/ABC 600 mg/DTG 50 mg tablet
3TC/ABC/ZDV (Trizivir):d
  • 3TC 150 mg/ABC 300 mg /ZDV 300 mg tablet
Standard Adult Dose
3TC (Epivir):
  • 3TC 150 mg twice daily or 300 mg once daily, without regard to food
3TC/TDF (Cimduo):
  • One tablet once daily without regard to food
3TC/ZDV (Combivir):
  • One tablet twice daily without regard to food
3TC/DOR/TDF (Delstrigo):
  • One tablet once daily without regard to food
3TC/DTG (Dovato):
  • One tablet once daily without regard to food
3TC/ABC (Epzicom):
  • One tablet once daily without regard to food
3TC/EFV/TDF (Symfi or Symfi Lo):
  • One tablet once daily on an empty stomach and preferably at bedtime
3TC/TDF (Temixys):
  • One tablet once daily without regard to food
3TC/ABC/DTG (Triumeq):
  • One tablet once daily without regard to food
3TC/ABC/ZDV (Trizivir):
  • One tablet twice daily without regard to food

PKs in Pregnancy:
  • PKs not significantly altered in pregnancy.

Dosing in Pregnancy:
  • No change in dose indicated.

For guidance about use of combination products in pregnancy, please see the specific sections on other components (i.e., ABC, DOR, DTG, EFV, TDF, ZDV)

High placental transfer to fetus.b

No evidence of human teratogenicity (can rule out 1.5-fold increase in overall birth defects).

If patient has HBV/HIV coinfection, it is possible that an HBV flare may occur if the drug is stopped; see Hepatitis B Virus/HIV Coinfection.

3TC products developed specifically for treatment of HBV (e.g., Epivir-HBV) contain a lower dose of 3TC that is not appropriate for treatment of HIV.

a Individual ARV drug dosages may need to be adjusted in patients with renal or hepatic insufficiency (for details, see the Adult and Adolescent Antiretroviral Guidelines Appendix B, Table 10).
b Placental transfer categories are determined by mean or median cord blood/maternal delivery plasma drug ratio:
          High: >0.6
          Moderate: 0.3–0.6
          Low: <0.3
d Generic formulation available

Key: 3TC = lamivudine; ABC = abacavir; ARV= antiretroviral; DOR = doravirine; DTG = dolutegravir; EFV = efavirenz; FDC= fixed-dose combination; HBV = hepatitis B virus; PK = pharmacokinetic; TDF = tenofovir disoproxil fumarate; ZDV = zidovudine


  1. Lamivudine [package insert]. 2018. Available at:,020596s037lbl.pdf.
  2. Mandelbrot L, Peytavin G, Firtion G, Farinotti R. Maternal-fetal transfer and amniotic fluid accumulation of lamivudine in human immunodeficiency virus-infected pregnant women. Am J Obstet Gynecol. 2001;184(2):153-158. Available at:
  3. Moodley J, Moodley D, Pillay K, et al. Pharmacokinetics and antiretroviral activity of lamivudine alone or when coadministered with zidovudine in human immunodeficiency virus type 1-infected pregnant women and their offspring. J Infect Dis. 1998;178(5):1327-1333. Available at:
  4. Benaboud S, Treluyer JM, Urien S, et al. Pregnancy-related effects on lamivudine pharmacokinetics in a population study with 228 women. Antimicrob Agents Chemother. 2012;56(2):776-782. Available at:
  5. Mirochnick M, Thomas T, Capparelli E, et al. Antiretroviral concentrations in breast-feeding infants of mothers receiving highly active antiretroviral therapy. Antimicrob Agents Chemother. 2009;53(3):1170-1176. Available at:
  6. Palombi L, Pirillo MF, Marchei E, et al. Concentrations of tenofovir, lamivudine and efavirenz in mothers and children enrolled under the option B-plus approach in Malawi. J Antimicrob Chemother. 2016;71(4):1027-1030. Available at:
  7. . Sibiude J, Mandelbrot L, Blanche S, et al. Association between prenatal exposure to antiretroviral therapy and birth defects: an analysis of the French perinatal cohort study (ANRS CO1/CO11). PLoS Med. 2014;11(4):e1001635. Available at:
  8. Antiretroviral Pregnancy Registry Steering Committee. Antiretroviral Pregnancy Registry international interim report for 1 January 1989–31 January 2019. Wilmington, NC: Registry Coordinating Center. 2019. Available at: http://www.
  9. Vannappagari V, Koram N, Albano J, Tilson H, Gee C. Abacavir and lamivudine exposures during pregnancy and non-defect adverse pregnancy outcomes: data from the antiretroviral pregnancy registry. J Acquir Immune Defic Syndr. 2015;68(3):359-364. Available at:
  10. Williams PL, Hazra R, Van Dyke RB, et al. Antiretroviral exposure during pregnancy and adverse outcomes in HIV-exposed uninfected infants and children using a trigger-based design. AIDS. 2016;30(1):133-144. Available at:

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