TABLE 3
Effect of race on unintended pregnancy and breastfeeding behavior
| Weighted adjusted odds ratio of NOT breastfeeding*† | ||||
|---|---|---|---|---|
| Intendedness of pregnancy | White (n=3661) | Hispanic (n=1063) | Black (n=1646) | |
| Initiation of breastfeeding (any) | ||||
| Intended | reference | reference | reference | |
| Unintended | 1.15 (0.93-1.42) | 0.94 (0.66-1.35) | 0.81 (0.56-1.17) | |
| Mis-timed | 1.07 (0.87-1.32) | 0.93 (0.64-1.35) | 0.78 (0.53-1.15) | |
| Unwanted | 2.50 (1.54-4.05) | 0.97 (0.55-1.70) | 0.93 (0.52-1.65) | |
| Continuation of breastfeeding (16 ≥ weeks) | ||||
| Intended | reference | reference | reference | |
| Unintended | 1.39 (1.07-1.81) | 1.08 (0.74-1.58) | 0.73 (0.44-1.20) | |
| Mis-timed | 1.29 (0.99-1.68) | 1.10 (0.76-1.60) | 0.70 (0.41-1.20) | |
| Unwanted | 2.56 (1.34-4.87) | 0.90 (0.47-1.72) | 0.78 (0.34-1.76) | |
| * National Survey of Family Growth sampling weights applied. | ||||
| † Adjusted for age, marital status, poverty level, and education. | ||||
Discussion
In this study of first-time US mothers, women who breastfed were demographically different from those who did not, but had relatively similar maternal behaviors and infant characteristics. After controlling for these demographic differences, having an unwanted pregnancy was associated with a lower likelihood of both initiating breastfeeding and continuing to breastfeed. In addition, race was an important effect modifier for unwanted pregnancies.
The demographic findings of this study are consistent with the current breastfeeding literature: US women who breastfeed tend to be older, white, married, well-educated, and of a higher socioeconomic status than those who do not.9 The main findings of this study are also consistent with the only other study that has examined the relationship between unintended pregnancy and breastfeeding behavior.10 A cross-sectional sample of 27,700 women who gave birth to a live baby were asked prior to postpartum discharge whether they had intended to become pregnant and their plans for breastfeeding. After controlling for education, race, Medicaid status, maternal age younger than 20, and any tobacco use during pregnancy, the authors found that women whose pregnancies were unintended were more likely not to initiate breastfeeding or to breastfeed exclusively. Adjusted odds ratios of not breastfeeding ranged from 1.10 to 1.41, depending on intention status, and all were statistically significant. In contrast to our study, a major limitation of that study was that the measured outcome was intent to breastfeed at hospital discharge, which may have differed greatly from actual breastfeeding behavior.
The interaction seen in our analysis between intention status and race is initially surprising because, in general, white and Hispanic women breastfeed at much higher rates than black women. But if a pregnancy was unwanted, white women were much less likely to breastfeed than either black or Hispanic women. Neither socioeconomic status nor educational level is the explanation, as both of these factors were controlled for in stratified analyses. Perhaps Hispanic and black women are more accepting of unintended pregnancy than white women and these results reflect cultural differences. Further studies which examine other aspects of unintended pregnancy with respect to race will help to further clarify the reasons for this finding.
Strengths and limitations
Our population-based study has several strengths. The data set provides a large national sample with excellent representation of minority women; statistical oversampling and weighting allow these data to reflect the entire national population. Adjustment of data for nonresponse lessens the risk of selection bias. Furthermore, the study sample was restricted to first births to limit the effect of previous birth experiences on postpartum behaviors. Therefore our results are generalizable to all first-time mothers in the United States.
A major limitation of our study is that information was not collected on several factors, such as substance use both during pregnancy and after birth, that might influence the relationship between pregnancy intention status and breastfeeding behavior. The work of Dye and colleagues,10 discussed above, found that prenatal tobacco, but not alcohol or drug use, was a significant confounder. Information was also not available on health service–related factors that may contribute to breastfeeding success, such as breastfeeding in the delivery room, length of hospital stay, and participation in educational programs.11
Given that data were collected for the NSFG during personal interviews at differing lengths of time after a pregnancy, inaccuracy is possible. Although the survey does not include corroboration from other sources, such as medical records or birth certificates, it is reassuring that, as an example, rates of prenatal care in our study are similar to those of other nationally reported rates for 1995 (98.1% in our study and 98.8% in National Vital Statistics Reports).12 Potential misclassification with respect to such medical outcomes as prematurity would be nondifferential and only bias odds ratios toward the null. The extended time between conception and measurement of maternal attitudes increases the uncertainty that a mother will accurately recall both her pregnancy intentions at conception and her breastfeeding practices. Women are more likely to recall a pregnancy carried to birth as intended, but this phenomenon would only bias the results if it also applied to breastfeeding practices, which is unlikely.13 While breastfeeding practices may not be exactly recalled, there is no obvious reason for differential reporting.