Marquette Method postpartum and breastfeeding research

The postpartum period is one of the hardest times to use any fertility awareness based method, because cycles often do not look like they did before pregnancy and ovulation can return before the first period. Marquette Method protocols are designed for this stage and combine urinary hormone monitoring with cervical mucus observations.

This research describes how that postpartum protocol performed in breastfeeding women who were taught the rules and used the monitor as instructed. It is one of the few clinical studies focused specifically on the breastfeeding return-of-fertility window.

What this research looked at#

The authors evaluated a postpartum transition protocol used by women who had recently given birth and were breastfeeding. The protocol asks users to monitor urinary hormones (luteinizing hormone and estrogen metabolites) using a specific home monitor and to also observe cervical mucus, with rules for when intercourse is considered to fall in or out of the fertile window.

What the study found#

Couples who followed the protocol identified fertile and infertile days in a way that could be tracked across the return-of-fertility transition. Pregnancies still occurred, particularly when couples had intercourse during identified fertile days, which is consistent with how every fertility awareness based method behaves. The authors concluded that a structured postpartum protocol is a reasonable option for breastfeeding women who want to use a fertility awareness based method.

What this means in plain English#

Breastfeeding does not freeze fertility, and the first ovulation after childbirth often happens before the first period. A protocol designed for this stage gives a couple a more concrete way to identify potentially fertile days than guessing or relying on cycle counting alone. It still requires consistent observations, instructor support, and acceptance that postpartum cycles can be unpredictable.

What this does not prove#

This research does not show that breastfeeding alone reliably prevents pregnancy, that any fertility awareness based method is equally effective postpartum and during regular cycles, or that an app or monitor alone replaces instruction. It also does not promise the same result for every individual; postpartum biology varies a lot.

Important limitations#

• The protocol depends on a specific commercial fertility monitor and on trained instruction.
• Sample sizes in postpartum NFP research are typically smaller than in non-postpartum studies.
• Postpartum hormone patterns are individual; results in a study population do not guarantee an individual outcome.
• Effectiveness drops if observations are skipped, the monitor is misused, or rules are not followed.

Why this matters for NFP education#

Many couples are told that breastfeeding will protect them or that they can simply resume their previous method, and both can be misleading. Research like this supports a more honest message: postpartum is its own stage, it benefits from a method designed for it, and instruction matters even more here than in regular cycles.

Related reading#

• Marquette Method overview, /methods/marquette
• Can I use NFP while breastfeeding, /questions/can-i-use-nfp-while-breastfeeding
• Postpartum, /glossary/postpartum
• Lactational Amenorrhea Method (LAM), /glossary/lam
• LH surge, /glossary/lh-surge
• Do I need a certified instructor, /questions/do-i-need-a-certified-instructor
• Life stages, /life-stages