Highlights
In this secondary analysis of the prospective nuMoM2b-HHS cohort, severe maternal morbidity (SMM) at delivery was not associated with whether nulliparous individuals initiated breastfeeding.
Among those who did breastfeed, SMM was associated with substantially lower odds of breastfeeding for more than 6 months, with an adjusted odds ratio (aOR) of 0.50 (95% CI, 0.36-0.68).
SMM was also associated with lower odds of exclusive breastfeeding among those who initiated breastfeeding, with an aOR of 0.60 (95% CI, 0.37-0.98).
The findings suggest that delivery-related maternal complications may exert their greatest effect not at breastfeeding initiation, but during the sustained postpartum period when physical recovery, infant care demands, and health system support intersect.
Background
Breastfeeding is associated with important maternal and infant health benefits, including reduced infant infections, lower risk of sudden infant death syndrome, and maternal benefits such as improved metabolic recovery and lower long-term cardiometabolic risk. Yet breastfeeding initiation and continuation are strongly shaped by social, structural, and medical factors. One of the less well-characterized barriers is severe maternal morbidity, a group of serious, potentially life-threatening complications that occur during labor and delivery or the immediate peripartum period.
In the United States, SMM has become a central quality and equity metric in obstetric care. The burden of SMM has increased over time, and the condition is unequally distributed across racial, ethnic, and socioeconomic groups. Although the impact of SMM on maternal survival, readmission, and long-term health has been widely discussed, less attention has been given to how these complications may affect postpartum behaviors and recovery trajectories, including breastfeeding.
That question is clinically important. Lactation initiation often begins within hours after birth and depends on maternal hemodynamic stability, pain control, early skin-to-skin contact, rooming-in, and infant feeding support. SMM may disrupt all of these. Hemorrhage, hypertensive emergencies, sepsis, respiratory failure, intensive care needs, and operative complications can separate mother and infant, delay lactogenesis, worsen fatigue, and complicate medication management. At the same time, some patients with serious peripartum complications may remain strongly motivated to breastfeed, particularly if they receive coordinated postpartum support. Therefore, it is not obvious whether SMM mainly affects initiation, duration, exclusivity, or all three.
The study by Bank and colleagues addresses this gap using data from a large, geographically diverse prospective cohort of nulliparous individuals in the United States. By focusing on first births, the analysis avoids confounding from prior breastfeeding experience and offers a clinically useful view of how serious maternal complications may influence early feeding trajectories.
Study Design
Design and data source
This investigation was a secondary analysis of the prospective nuMoM2b-HHS cohort. The parent nuMoM2b study enrolled nulliparous pregnant individuals across the United States and collected detailed clinical and follow-up information, making it a valuable platform for evaluating postpartum outcomes beyond delivery.
Population
The analytic sample included 6,762 nulliparous individuals. The exclusive focus on nulliparous participants is a major design strength because previous breastfeeding success or difficulty can strongly influence subsequent breastfeeding behaviors. Restricting the study to first births therefore improves internal validity for evaluating the association between SMM and postpartum feeding outcomes.
Exposure
The main exposure was severe maternal morbidity at delivery. The abstract reports both overall SMM and nontransfusion SMM frequencies. Any SMM occurred in 160 participants (2.4%), while nontransfusion SMM occurred in 124 (1.8%). This distinction is clinically meaningful because transfusion-only SMM can sometimes represent a heterogeneous group, ranging from isolated hemorrhage management to more complex multisystem morbidity.
Outcomes
The main breastfeeding outcomes were initiation, duration of any breastfeeding, and exclusive breastfeeding. Among the 6,762 participants, any breastfeeding by duration was distributed as follows: 759 (11.2%) breastfed for less than 6 weeks, 1,847 (27.3%) breastfed for 6 weeks to 6 months, and 3,359 (49.7%) breastfed for more than 6 months. Among those with any breastfeeding, 4,653 (85.4%) reported exclusive breastfeeding.
The abstract emphasizes adjusted analyses, indicating that the investigators accounted for measured confounders when estimating associations between SMM and breastfeeding outcomes. The specific covariates are not provided in the abstract, but in studies of this type they commonly include maternal demographics, obstetric factors, neonatal characteristics, and postpartum variables that can influence feeding outcomes.
Key Findings
Breastfeeding initiation was not reduced by severe maternal morbidity
The first major finding is clinically reassuring: breastfeeding initiation did not vary by SMM status. In other words, individuals with serious delivery complications were still broadly as likely to start breastfeeding as those without SMM. This suggests that in-hospital efforts to initiate lactation may still succeed despite acute maternal illness, or that patient intention to breastfeed remains high even after a complicated delivery.
From a care-delivery perspective, this is important because it argues against a simplistic assumption that SMM inevitably prevents the start of breastfeeding. Hospitals should not interpret severe maternal complications as a reason to de-emphasize lactation support. Rather, the data suggest that many patients with SMM do begin breastfeeding, and therefore represent a population in whom targeted support may help preserve longer-term breastfeeding goals.
SMM was strongly associated with shorter breastfeeding duration
The central finding of the study is that among participants who breastfed, SMM was associated with a markedly lower likelihood of breastfeeding for more than 6 months. The adjusted odds ratio was 0.50 (95% CI, 0.36-0.68). This is a large effect size. Interpreted clinically, the odds of sustained breastfeeding beyond 6 months were reduced by about half among those experiencing SMM at delivery compared with those without SMM.
The confidence interval is relatively tight and does not cross 1.0, supporting statistical significance and suggesting a robust association. Because the effect persisted after adjustment, the finding is unlikely to be fully explained by measured demographic or obstetric differences alone.
This result may be more clinically meaningful than an initiation outcome. Breastfeeding duration depends on ongoing maternal health, recovery, infant contact, confidence, social support, and access to outpatient lactation services. SMM may impair all of these over weeks to months. Patients recovering from major hemorrhage, hypertensive complications, surgical morbidity, cardiopulmonary instability, or intensive care admission may face prolonged fatigue, physical limitations, repeated medical visits, mood symptoms, and delayed functional recovery. Those burdens can make sustained breastfeeding difficult even if lactation was initiated in the hospital.
SMM was also associated with lower exclusive breastfeeding
Among those who initiated breastfeeding, SMM was associated with lower odds of exclusive breastfeeding, with an adjusted odds ratio of 0.60 (95% CI, 0.37-0.98). Although the confidence interval is wider and approaches 1.0, it still indicates a statistically significant reduction in the likelihood of exclusive breastfeeding.
This finding is plausible biologically and operationally. Exclusive breastfeeding is often more fragile than any breastfeeding because it can be disrupted by supplementation in the nursery, delayed onset of mature milk production, maternal-infant separation, neonatal intensive care admission, maternal medication concerns, or reduced confidence in milk supply after a medically complex birth. Even a temporary early disruption can shift families toward combination feeding, which may persist long term.
Absolute outcome patterns provide useful clinical context
The study also provides helpful descriptive context for breastfeeding in this cohort. Nearly half of the full cohort breastfed for more than 6 months, and a high proportion of those who initiated breastfeeding reported exclusive breastfeeding. These rates suggest that the underlying cohort had relatively strong breastfeeding uptake overall. That matters when interpreting the adjusted results: the negative association between SMM and breastfeeding duration emerged despite generally favorable breastfeeding patterns in the study population.
If anything, this raises the possibility that the effect of SMM could be even more consequential in less advantaged populations or in care settings with fewer postpartum lactation resources. In populations where breastfeeding continuation is already difficult, the added burden of SMM may have an even larger practical impact.
Clinical Interpretation
The most useful conceptual contribution of this study is its distinction between breastfeeding initiation and breastfeeding persistence. The data indicate that the main vulnerability after SMM is not necessarily getting breastfeeding started, but maintaining it over time and sustaining exclusivity.
That distinction should reshape how clinicians think about postpartum support after obstetric complications. Standard maternity care often concentrates lactation counseling in the immediate postpartum hospitalization. However, if SMM primarily undermines later breastfeeding, then the window of greatest risk may extend well beyond discharge. Patients recovering from SMM may need structured outpatient follow-up, proactive lactation referrals, medication counseling, mental health assessment, and coordination across obstetric, primary care, and pediatric settings.
There are several biologically and clinically plausible mechanisms. Severe hemorrhage may contribute to delayed lactogenesis through pituitary hypoperfusion, anemia, or profound fatigue. Hypertensive disorders may require maternal-infant separation, magnesium therapy, or intensive monitoring, all of which can interfere with early feeding rhythms. Sepsis, cardiopulmonary complications, and operative morbidity can prolong hospitalization and delay maternal functional recovery. Pain, sleep disruption, and psychological distress may further reduce confidence and milk expression frequency. In addition, infants born after complicated deliveries may themselves require higher-level care, limiting direct breastfeeding opportunities.
The study also has implications for maternal health equity. Because SMM disproportionately affects historically marginalized populations in the United States, any downstream effect on breastfeeding duration may widen existing inequities in infant feeding outcomes. This means SMM may act not only as an acute obstetric event but also as a mechanism linking delivery complications to longer-term disparities in maternal-child health.
Strengths and Limitations
Strengths
The study has several notable strengths. First, it uses a large prospective multicenter cohort, enhancing data quality and reducing some forms of recall bias. Second, the focus on nulliparous individuals is methodologically strong because it removes prior breastfeeding history as a major source of confounding. Third, the study examines breastfeeding in a nuanced way, distinguishing initiation, duration, and exclusivity rather than reducing lactation to a single yes-or-no outcome. Finally, the availability of both overall SMM and nontransfusion SMM frequencies suggests thoughtful attention to exposure definition.
Limitations
As with any observational study, residual confounding remains possible. The abstract does not list the full adjustment set, so readers cannot fully assess whether all relevant social, neonatal, and health-system factors were captured. Breastfeeding outcomes may be influenced by variables such as return to work, insurance continuity, access to lactation services, family support, and neonatal illness severity, which are not always measured comprehensively.
The abstract also does not specify which components of SMM were most strongly associated with breastfeeding outcomes. SMM is a heterogeneous construct, and the pathway from postpartum hemorrhage to breastfeeding difficulty may differ substantially from the pathway for sepsis, respiratory failure, stroke, or eclampsia. Future work would benefit from disaggregating SMM phenotypes.
Generalizability should also be considered. Although the cohort is geographically diverse, participation in a prospective study may correlate with higher engagement in care than is typical in all U.S. birthing populations. In addition, the findings apply specifically to nulliparous individuals and may not translate directly to multiparous patients, whose prior breastfeeding experience can alter both resilience and vulnerability.
Finally, odds ratios do not directly communicate absolute risk differences. While the relative associations are compelling, clinicians and policymakers would benefit from future reports quantifying absolute reductions in long-duration and exclusive breastfeeding after SMM to guide resource allocation and counseling.
Implications for Practice and Policy
This study supports a practical change in postpartum care: patients with SMM should be considered at elevated risk for early breastfeeding discontinuation even when they successfully initiate breastfeeding in the hospital. This should trigger enhanced follow-up rather than reassurance based solely on initiation.
Potential care strategies include early postdischarge lactation appointments, home visiting or telelactation for patients recovering from complicated births, anemia and pain management, medication review compatible with breastfeeding, screening for postpartum depression and post-traumatic stress symptoms, and deliberate coordination with neonatal care teams when maternal-infant separation occurs.
At the systems level, hospitals and payers may wish to integrate lactation support into maternal morbidity recovery pathways. Just as SMM survivors may need surveillance for blood pressure, thromboembolism risk, or cardiometabolic sequelae, they may also need structured support for feeding goals. Such integration would align with broader efforts to improve the “fourth trimester” and reduce preventable postpartum attrition from desired breastfeeding.
Funding and ClinicalTrials.gov
The provided abstract and citation do not specify funding details or a ClinicalTrials.gov registration number for this secondary analysis. The study was conducted within the nuMoM2b-HHS framework, but readers should consult the full article for source funding, parent cohort support, and any applicable trial or cohort registration information.
Conclusion
Bank and colleagues provide clinically important evidence that severe maternal morbidity at delivery may not prevent breastfeeding from starting, but it does appear to compromise breastfeeding persistence and exclusivity among nulliparous individuals in the United States. The signal is substantial, especially for breastfeeding beyond 6 months, where the adjusted odds were reduced by half.
The findings shift attention from the delivery room alone to the months that follow. For patients surviving major obstetric complications, the question is often not whether breastfeeding begins, but whether the health system can support it long enough to continue. In that sense, breastfeeding duration may function as a meaningful postpartum recovery outcome, one that reflects the intersection of maternal physiology, neonatal care, and the strength of longitudinal support after a complicated birth.
Future research should identify which SMM phenotypes are most disruptive to lactation, clarify modifiable mediators such as maternal-infant separation and delayed lactogenesis, and test targeted postpartum interventions. Until then, clinicians should view SMM as a marker for intensified breastfeeding support rather than a reason to lower expectations.
References
1. Bank TC, Wu J, Catov J, Yee LM, Haas D, McNeil R, Ranzini AC, Simhan HN, Reddy U, Hoffman M, Silver RM, Levine L, Saade G, Chung J, Lynch CD, Grobman WA, Venkatesh KK. Severe Maternal Morbidity and Breastfeeding Among Nulliparous Individuals in the United States. Obstetrics and gynecology. 2026-06-04. PMID: 42241707.
2. American College of Obstetricians and Gynecologists. Optimizing Support for Breastfeeding as Part of Obstetric Practice. Committee Opinion No. 756. Obstet Gynecol. 2018;132:e187-e196.
3. Centers for Disease Control and Prevention. Severe Maternal Morbidity in the United States. CDC maternal health resources. Accessed for clinical context on SMM definitions and public health burden.
4. Victora CG, Bahl R, Barros AJD, et al. Breastfeeding in the 21st century: epidemiology, mechanisms, and lifelong effect. Lancet. 2016;387(10017):475-490.
