Below are some of the latest studies around the link between breastfeeding and maternal weight. Find out about the impact of breastfeeding on infant overweight and obesity in our infant health research section.
Breastfeeding reduces obesity in middle-aged mothers
A large UK study recruited 1 million middle aged women with an aim of examining the relationship between childbearing and breastfeeding and subsequent body mass index (BMI). A total of 980,474 women were included in the main analysis, 87 per cent of whom were parous, with 68 per cent having a history of ever breastfeeding. The mean lifetime duration of breastfeeding per child was 3.8 months. Mean BMI increased significantly with each birth from 25.8 for nullips to 28.1 for women with five or more births. Women who breastfed had significantly lower BMIs and this remained significant even after adjusting for confounding variables.
The authors conclude that whilst BMI increased with increasing parity, this increase would be offset if women breastfed. They argue that the findings contribute to the body of evidence that childbearing and breastfeeding have sustained long-term effects on the health status of women.
Bobrow K, Quigley M, Green J et al (2009) The Long Term Effects of Childbearing and Breastfeeding on Body Mass Index in Middle Aged Women: Results from the Million Women Study. J Epidemiol Community Health; 63 (Suppl_2): 56
Does breastfeeding help mothers to lose weight gained during pregnancy?
Weight gained during pregnancy and not lost postpartum may contribute to obesity in women of childbearing age. A large study was carried out in Denmark where the population traditionally breastfeeds exclusively and for a lengthy duration. Statistical analyses were used to investigate whether breastfeeding duration and intensity reduced postpartum weight retention (PPWR) at both times. Adjustment was made for maternal pre-pregnancy body mass index (BMI) and weight gain during pregnancy. The researchers found that weight gain during pregnancy was significantly associated with PPWR at both six and 18 months postpartum (P < 0.0001). Breastfeeding reduced PPWR in all but the mothers with the greatest pre-pregnancy BMI at both 6 months (P < 0.0001) and 18 months (P < 0.05) postpartum. They estimated that if women exclusively breastfed for 6 months as is recommended, PPWR could be eliminated by that time in women with pregnancy weight gain of approximately 12 kg, and that the possibility of major weight gain (5 kg) could be reduced in all but the heaviest women.
Does obesity impact on breastfeeding success?
It has been observed that a possible link exists between high pre-pregnant body mass index (BMI) and early termination of breastfeeding. A large study in Denmark was conducted to determine whether this association was affected by obesity alone or was associated with the amount of social support available for breastfeeding. The study found that the greater the pre-pregnant BMI, the earlier the termination of breastfeeding, irrespective of weight gain in pregnancy. Together with the fact that this association was evident when a supportive social context for breastfeeding existed, these findings suggest a possible biological basis for the association and therefore further research is indicated.
Does maternal obesity impact on breastfeeding outcomes?
An association has been suggested between maternal obesity and low breastfeeding rates. A systematic review was conducted to assess the association between maternal obesity and infant feeding intention, initiation, duration and delayed onset of lactation. The authors found that obese women plan to breastfeed for a shorter period than normal weight women and are less likely to initiate breastfeeding. The authors conclude that overweight and obese women are less likely to breastfeed than normal weight women. The reasons may be biological or they may be psychological, behavioral and/or cultural. They suggest that qualitative studies from women’s perspective to help understand their behaviour and infant feeding decisions in this situation are urgently needed.