Tools for Practice


    #320 Oh Baby: Combined oral contraceptives during breastfeeding


    CLINICAL QUESTION
    Do combined oral contraceptives (COCs) affect breastfeeding or infant outcomes?

    BOTTOM LINE
    Trials are older (>35 years), small (<300 mom/infants) and highly unreliable. If results are real, COCs may lower infant growth (by~240g) and rates of exclusive breastfeeding (81% versus 92%) compared to placebo at 90 days. Progestin-only pill (POP) evidence is inconsistent/unreliable. If results are real, infant growth is not different compared to placebo. If early postpartum contraception is desired, guidelines recommend progestin-only methods due to increased venous thromboembolism risk.


    EVIDENCE
    • Randomized controlled trials (RCTs) from two systematic reviews.1,2 Oral contraceptives started 2-6 weeks postpartum. Results statistically different unless indicated.
    • COC versus placebo:
      • Infant weight:
        • 182 women, ethinyl estradiol 30mcg/levonorgestrel 0.15mg:3
          • At 91 days postpartum: 6011g versus 6250g (placebo).
        • 50 women, mestranol 80mcg with progestin:4
          • Between weeks 2-5 postpartum: Weight gain ~7oz less versus placebo, statistics not reported.
      • Exclusive breastfeeding:
        • At 91 days:3 81% versus 92% (placebo).
      • Supplemental formula:
        • At 91 days:3 Proportion supplementing: 18% versus 8% (placebo), not statistically different.
        • At 5 weeks:4 ~710 versus 190 supplemental calories/week (placebo), statistics not reported.
    • POP versus placebo:
      • Started ≤6 weeks postpartum: Two low-quality RCTs (20 and 400 women).5,6
        • Infant growth: No difference.2
    • COC versus POP:
      • Largest RCT (171 women) comparing ethinyl estradiol 30mcg/levonorgestrel 150mcg versus levonorgestrel 150mcg over 6-24 weeks postpartum:7
        • No difference: Infant weight or supplementation.
        • Milk volume: Decreased 42% COC vs 12%.
      • Results consistent with other RCT (127 women);8
        • No difference: Breastfeeding or adverse effects at 6 months.
    • Limitations: Old trials (>35 years);3-5,7 incomplete reporting;3,4,7 underpowered;8 high drop-outs;7,8 unclear randomization;3 some formulations/doses no longer used.4,9
    • COC adverse effects on mother/child pairs from non-RCTs:
      • 48 pair: No difference in growth/intellectual development versus control, ≤8 years.9
      • 103 versus 227 pairs (placebo/intrauterine device): No difference in infant breast/genital changes at 1 year.10
    Context
    • Guidelines recommend:
      • Progestin-only contraception during early postpartum period.11,12
      • Against COC within first 4-6 weeks postpartum while breastfeeding due to venous thromboembolism risk.12,13
        • Early postpartum risk is 15-35 times non-pregnant,12,14 returning to baseline at 6-12 weeks.14

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    Author(s):

    • Allison Paige MD CCFP
    • Jennifer Potter MD CCFP
    • Samantha Moe PharmD

    1.Tepper NK, Phillips SJ, Kapp N, et al Contraception. 2016; 3(94): 262-74.

    2.Lopez LM, Grey TW, Stuebe AM, et al. Cochrane Database Syst Rev. 2015; 3:CD003988.

    3.Diaz S, Peralta O, Juez G, et al. Contraception. 1983; 27:1:1-11.

    4.Miller GH, Hughes LR. Obstet Gynecol. 1970; 35(1):44-50.

    5.Giner Velazquez, Cortes Gallegos V, Sotelo Lopez A, et al. Ginecol Obstet Mex 1976; 40(237):31-9.

    6.Dutta DK, Dutta I. J Indian Med Assoc 2013; 111(8):553-5.

    7.Tankeyoon M, Dusitsin N, Chalapati, S, et al. Contraception. 1984; 30(6):505-22.

    8.Espey E, Ogburn T, Leeman L et al. Obstet Gynecol. 2012; 119(1):5-13.

    9.Nilsson S, Mellbin T, Hofvander Y, et al. Contraception. 1986; 34(5):443-57.

    10.Croxatto HB, Diaz S, Peralta O, et al. Contraception. 1983: 27(1):13-25.

    11.Black A, Guilbert E, Costescu D, et al. JOGC. 2016; 38(3):279-300.

    12.The Faculty of Sexual and Reproductive Healthcare. https://www.fsrh.org/standards-and-guidance/documents/contraception-after-pregnancy-guideline-january-2017/. Accessed June 29, 2022.

    13.Black A, Guilbert E, Costescu D, et al. JOGC 2017; 39(4): 229-268.

    14.Thrombosis Canada. https://thrombosiscanada.ca/wp-uploads/uploads/2021/11/42.-Pregnancy-Diagnosis-of-DVT-and-PE_14Sept2021.pdf. Accessed June 29, 2022.

    Authors do not have any conflicts of interest to declare.