Sexual and reproductive health clinical consultations: breastfeeding and progestogen-only contraception

Clinical case

Susan is a 27-year-old G2P2 (gravida 2, para 2) who is 1 day postpartum from a term uncomplicated vaginal birth of a healthy baby. She is planning to breastfeed her newborn. She had a positive experience exclusively breastfeeding her older daughter for 3 months, but stopped after returning to work because it was difficult to continue to express and store milk.

She used combined oral contraceptive pills before her first pregnancy and progestogen-only pills after the birth of her first child. She reports that it was more difficult to remember to take the pill while caring for a newborn. She has no other pertinent medical history.

Background

Multiple global health organisations recommend exclusive breastfeeding for the first 6 months of life. The relationship between lactation and the return to fertility is finely balanced and must each align with the patient’s goals in both domains. While lactational amenorrhea (LAM) is highly effective (98%) in the setting of exclusive direct breastfeeding within the first 6 months postpartum, the efficacy decreases as complementary foods are introduced and nighttime feeding becomes less frequent.¹ The contraceptive efficacy of lactational amenorrhea has not been established for individuals who express breast milk by pumping, even if their milk is the exclusive source of nutrition for their infant. For these reasons and more, many people desire initiation of more reliable contraceptive methods while breastfeeding in the first 3–6 months postpartum. Additionally, the early postpartum period, particularly the first 6 weeks postpartum, carries an increased risk of deep venous thrombosis and thus contraceptive choices are temporarily limited to progestogen-only and non-hormonal methods to mitigate this risk.

Concerns and misinformation regarding contraception, breastfeeding and milk supply can complicate contraceptive counselling and uptake. Most healthy postpartum individuals can be safely offered progestogen-only methods including pills, injectables (depo medroxyprogesterone acetate (DMPA), norethisterone enanthate (NET-EN)), progesterone vaginal ring (PVR), implants (levonorgestrel (LNG), etonorgestrel (ETG)) and intrauterine devices (LNG IUD) (table 1).

Table 1.

WHO medical eligibility criteria for progestogen-only contraception while breastfeeding ⁶

	Implant	Progestogen-only injectables	Progestogen-only pills
<42 days (less than 6 weeks)	2	2	2
>42 days (6 weeks or more)	1	1	1
	Levonorgestrel Intrauterine devices (IUD)
<10 min after placenta	2
10 min after placenta to <4 weeks postpartum	2
≥4 weeks postpartum	1
Postpartum sepsis including chorioamnionitis or endometritis	4

The WHO MEC criteria are as follows: (1) no restriction for the use of the contraceptive method; (2) the advantages of using the method generally outweigh the theoretical or proven risks; (3) the theoretical or proven risks usually outweigh the advantages of using the method; (4) an unacceptable health risk of the contraceptive method is used.

BMI, body mass index; MEC, medical eligibility criteria; VTE, venous thromboembolism.

Breastfeeding is not a contraindication to progestogen-only contraception. Although progestogens can be detected in breast milk at low levels, there are no known adverse health outcomes to newborns and infants due to these exposures.

Individuals at risk of low milk supply (box 1) who prioritise breastfeeding may want to wait until lactogenesis is established (approximately 4–6 weeks). Some risk factors for low milk supply can be identified before birth, while others are contextual, so ongoing assessment of infant feeding goals is critical.

Box 1. Examples of risk factors for low milk supply.

Prior to birth

• Insufficient glandular tissue

• Prior breast surgeries including reductions or augmentation

• Obesity

• Diabetes

• History of low milk supply in prior pregnancy

After birth

• Postpartum haemorrhage

• Caesarean birth

• Prematurity

• Separation from infant

• Infant anatomic or neurologic conditions leading to ineffective latch

• Failure to return to birth weight by 1 week old

The definitive impact of progestogen-only contraception on initiation and maintenance of lactation is harder to quantify due to the dynamic nature of both lactation and risk factors for low milk supply. Lactogenesis is partially catalysed by the rapid decrease in progesterone following delivery. Figure 1 illustrates the key events that occur with lactation and how that relates to the recommendations for initiation of progestogen-only contraception. During lactogenesis, milk transitions from colostrum to mature milk over approximately 1–2 weeks (figure 1). Mature milk volume continues to rise until approximately 6 weeks postpartum, after which milk volume remains largely stable. Milk composition will continually change to meet infant nutritional needs. Milk volume begins to decrease once the infant starts complementary foods. Progestogen-only contraceptive exposure could theoretically delay lactogenesis if initiated in the immediate postpartum period, but studies have not demonstrated this.

Figure 1.

Timeline of key events in establishment of lactation relative to recommendations for initiation of progestogen-only contraception in breastfeeding individuals. Shortly after birth colostrum transitions to milk. The full transition to mature milk can take up to 2 weeks. Thereafter, the milk volume increases until volume stabilizes between 4 and 6 weeks postpartum. Use of progestogen-only contraceptives after birth while breastfeeding is safe. At or after six weeks from birth (vertical line), all methods are WHO Category 1. In the setting of risk factors for low milk supply, some patients may want to delay initiation of progestogen-only contraception until establishment of mature milk or peak milk production volume.

How soon can someone start progestogen-only contraception when breastfeeding?

Progestogen-only contraception can be initiated immediately after delivery for most people (<6 weeks: WHO medical eligibility criteria (MEC) 2; 6 weeks and over: MEC 1) but it is important to provide counselling and options through shared decision making. Evidence is reassuring overall regarding starting a progestogen-only method and breastfeeding in individuals without risk factors for low milk supply. For individuals with risk factors for low milk supply who desire prioritising lactation, initiation of progestogen-only contraception can be delayed to 4–6 weeks postpartum. This delay may aid in the establishment of lactation while trending infant weight or working with lactation specialists to optimise breastfeeding. However, supplementation with formula expedites return to fertility and may increase the risk of unplanned short interval pregnancies.

User-initiated methods include progestogen-only pills. There are few data informing the risk of delayed lactogenesis or breastfeeding duration associated with progestogen-only pills before 4 weeks postpartum, but the potential benefits outweigh the harms (initiation of pills <6 weeks: MEC 2).² Given barriers to care and access, patients may benefit from having these methods prescribed for them at the time of birth and being empowered to initiate them when desired. Another potential advantage of these methods is the ability to stop a method easily as desired if risk factors for low milk supply develop.

Injectable contraception using DMPA or NET-EN is safe to administer in the weeks following birth, despite the relatively high progestogen dose (<6 weeks: MEC 2, 6 weeks and over: MEC 1). DMPA administered immediately postpartum after term delivery has not been shown to delay lactogenesis, but in the preterm setting, DMPA immediately postpartum was associated with a delay in lactogenesis by half a day, which may or may not be clinically important.³ Because DMPA only provides contraception up to 13 weeks (with a grace period of up to 15 weeks for the next injection), ensuring ongoing access to care or self-administered subcutaneous DMPA is critical for people who desire continued use.

Some patients may be interested in long-acting reversible contraception such as an LNG IUD or the contraceptive implant with LNG or ETG, which have low and consistent systemic progestogen doses but require healthcare providers to place and remove the devices. Placement of the implant is not altered by postpartum physiology. In the absence of risk factors for low milk supply, implant placement within 24 hours of delivery does not change the onset of lactogenesis or the rates of exclusive breastfeeding (MEC 2).⁴

When comparing post-placental LNG IUD placement to delayed placement at 6–8 weeks postpartum, there was no difference in breastfeeding initiation or continuation.⁵ However, risks of IUD placement differ based on placement timing including a higher risk of expulsion with post-placental placement (immediate to <4 weeks: MEC 2, >4 weeks: MEC 1). The IUD should not be placed in the setting of concern for uterine infections such as chorioamnionitis or postpartum endometritis (MEC 4), but once treated the IUD may be initiated.

Outcome

Susan was discharged from the hospital without complication. She experienced a similar onset of lactogenesis as in her first pregnancy and was breastfeeding her infant without complication. At her newborn’s 1 week check-up, she had surpassed her birth weight. At Susan’s 6 week postpartum visit, she desired to start an injectable for contraception and was able to receive the injection before leaving the clinic. She continued to exclusively breastfeed her daughter for a total of 6 months without any difficulties.

Data availability statement

No data are available.

Ethics statements

Patient consent for publication

Not applicable.

Ethics approval

Not applicable.