GRADE table 2(Questions 2): Among breastfeeding women, does initiation of combined hormonal contraceptives (CHCs) at > 6 weeks postpartum have negative effects on breastfeeding outcomes or infant outcomes, compared with no contraception or non-hormonal contraception? (Direct evidence)

OutcomeType and number of studies (number of participants)LimitationsInconsistencyImprecisionIndirectnessOther factorsQualityEstimate of effect
Combined oral contraceptive (COC) initiated at ≥ 6 weeks postpartum vs non-hormonal or non-use
Breastfeeding continuation2 non-randomized studies (n=339)Serious limitations
(2 fair)		No serious inconsistencyNo serious imprecisionNo indirectnessNoneLow2 non-randomized studies found no difference between ethinyl estradiol (EE) COC vs non-COC (various) in breastfeeding continuation rates at 6 or 12 months (RR 0.96–0.99 in both studies)
Duration of breastfeeding1 cohort study (n=96)Serious limitations
(1 fair)		Cannot determine
(1 study)		Serious imprecisionNo indirectnessNoneVery low1 cohort study found no difference between EE COC vs no oral contraceptives in duration of breastfeeding (3.7 vs 4.6 months, P < 0.05)
Breastfeeding episodes1 cohort study (n=20)Serious limitations
(1 fair)		Cannot determine
(1 study)		Very serious imprecisionNo indirectnessNoneVery low1 small study found EE COC associated with more breastfeeding episodes than IUD on 7 of 21 days from postpartum day 42 to day 63 with no differences on other days
Use of supplementation3 non-randomized studies; 1 cohort study (n=359 plus 1 study with < 50 women)Serious limitations
(3 fair, 1 poor)		Serious inconsistencySerious imprecisionNo indirectnessNoneLow2 fair-quality non-randomized studies found EE COC associated with increased likelihood of use of supplementation vs non-COC (various) at 3–12 months (differences ranged from 10–25% at various time points); 1 cohort study found no difference; 1 study found no difference between mestranol COC and IUD in age at supplementation
Infant growth2 non-randomized studies; 3 cohort studies (n=455 plus 1 study with < 50 women)Serious limitations
(3 fair, 1 poor)		Serious inconsistencySerious imprecisionNo indirectnessNoneLow1 cohort study found EE COC associated with lower infant growth vs non-COC (various) from 3–4 months (599 vs 708 g) but not at 5–6 months and no difference in mean weight at 1 year; 1 non-randomized study found no difference in change in weight at 12–16 or 20–24 weeks; 1 non-randomized study found mestranol COC 0.1 mg with more infant growth than 0.075 mg or IUD; 1 cohort study found no difference in infant growth through 8 years; 1 cohort study showed no difference between EE COC and IUD from day 42 to 63

COC: combined oral contraceptive; EE: ethinyl estradiol; IUD: intrauterine device; RR: relative risk.

From: I, Development of the Medical eligibility criteria for contraceptive use, fifth edition

Cover of Medical Eligibility Criteria for Contraceptive Use
Medical Eligibility Criteria for Contraceptive Use. 5th edition.
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