Among the respondents who participated in IFPS II, cesarean delivery was negatively associated with exclusive breastfeeding at hospital discharge. This association was independent of age, marital status, education, income, BMI, gestational weight gain, prenatal smoking, gestational age, NICU stay, previous cesarean delivery, and prenatal intent to exclusively breastfeed. However, among those who delivered by cesarean birth, the odds of exclusive breastfeeding at hospital discharge did not differ by the type of cesarean delivery, indicating that any cesarean delivery (planned or unplanned) was negatively associated with exclusive breastfeeding at discharge.
Our findings are consistent with and add to existing literature that has reported a negative association between cesarean delivery and breastfeeding.
11,13 The mechanisms for having lower odds of exclusive breastfeeding at hospital discharge could be multifactorial, including hormonal, social, or procedural causes.
19-22 For example, several studies have shown that certain types of anesthesia can affect lactation.
23-25 Other possible causes include delayed breastfeeding initiation after cesarean delivery, maternal-newborn separation, and possible delayed lactogenesis.
26-28
The 2 widely known hormones that play a major role in lactation are the pituitary hormones prolactin and oxytocin.
29 Milk production is controlled by prolactin levels, and milk ejection occurs in response to a surge in oxytocin.
29 Prolactin periodically surges to stimulate many processes during pregnancy, including lactation and breast tissue development.
30 Several studies have explored the specific roles and mechanism of action of the hormone prolactin during pregnancy and postpartum period.
31-33 After delivery of the placenta, the inhibitory factors of prolactin decrease, including progesterone and other placental hormones.
34 Further investigation of the biochemical mechanism of action associated with MOD on hormonal changes that affect lactation is important.
The current study found other factors that showed statistically significant associations with increased odds of exclusive breastfeeding at hospital discharge. These factors included race or ethnicity, education, gestational age, and prenatal intention to exclusively breastfeed, all of which have been previously noted.
26,35-37 A strong positive association was found between maternal prenatal intention to breastfeed and breastfeeding at hospital discharge (OR, 11.03; 95% CI, 8.19-14.84), supporting the need for education about breastfeeding. Several studies evaluating the effectiveness of prenatal breastfeeding education have found that prenatal breastfeeding education has a potential to improve breastfeeding rates.
38-41 Providing extra prenatal education for mothers who are planning to have a cesarean delivery could improve exclusive breastfeeding by increasing their intentions to breastfeed. Mothers need to be aware of the possible effect cesarean deliveries have on breastfeeding before making a decision. Early postnatal breastfeeding education and assistance for women who have either a planned or emergency cesarean delivery can also support improved breastfeeding outcomes.
A limitation of the current study is that the IFPS II data were collected by women volunteering to complete a mailed survey, which makes it susceptible to volunteer bias, recall bias, and selection bias. This problem is further exacerbated by a loss of 41% of the eligible study sample due to incomplete information. The final analytical sample statistically significantly differed from those with incomplete data by key sociodemographic characteristics, indicating that the results may not be generalizable to the IFPS II study sample (
Table 4). However, IFPS II is not a nationally representative dataset and may not produce results that can be generalized to all newborns, pregnant women, and new mothers in the United States. In addition, IFPS II data did not make any distinction between “exclusive breastfeeding at the time of maternal discharge” and “exclusive breastfeeding at the time of infant discharge.” The lack of this distinction could lead to a potentially misleading assumption that newborns who were discharged after their mothers would have the same access to breastfeeding as those who were discharged with their mothers. Likewise, the dichotomous variable of NICU stay (≤3 days) assumes that newborns who spent 3 days or fewer in the NICU could have similar access to breastfeeding as newborns who did not spend any time in the NICU.
The dataset also lacks important factors like timing of breastfeeding initiation. Furthermore, the cross-sectional design does not allow inference regarding causal relationships. In addition, given that this research is based on a secondary analysis of nearly decade-old data, the results should be interpreted with caution because guidelines for breastfeeding mothers, including those who have had a cesarean delivery, have improved after 2005 at most labor and delivery centers as a result of consumer demand, The Joint Commission, the Surgeon General’s Call to Action to Support Breastfeeding, the Centers for Disease Control and Prevention’s Maternity Practices in Infant Nutrition and Care, the World Health Organization, and the United Nations International Children’s Emergency Fund’s Baby-Friendly Hospital Initiative. A large national sample size, the diversity of the women who responded to the survey, and our ability to adjust for as many confounding variables as possible constitute some of the strengths of the current study.
Breastfeeding provides many nutritional, immunologic, and health benefits for newborns and infants.
9 Regardless of the type of delivery, mothers and newborns should be able to take advantage of this natural form of nutrition. Future research should focus on identifying specific causes of poor breastfeeding rates in women who undergo cesarean delivery. Further research is needed to understand the mechanism of lactation among women who have undergone a cesarean delivery as well as the role of conditions surrounding unplanned cesarean delivery. Understanding this mechanism is important because it can lead to the development of techniques to improve exclusive breastfeeding among these mothers.