My mother has been a huge advocate for ecological breastfeeding as long as I can remember - both my brother and I were breastfed past age three, my mother was very active as a La Leche League leader, and my mother remains very outspoken on the benefits of breastfeeding for babies and mothers. One of the benefits my mother has always mentioned is that breastfeeding naturally spaces babies - providing mothers and families with a healthy period of time to adjust to a new baby.
Ecological breastfeeding (EBF) describes a type of exclusive breastfeeding where a baby is nursed frequently, on demand, and spends most of her time, waking and sleeping, with her mother. Ecological breastfeeding is defined by a set of seven standards, and differs from cultural breastfeeding in that it does not include supplementing with formula, pacifiers, schedules, or separated sleeping. While cultural breastfeeding has little influence on fertility, ecological breastfeeding delays a mother's return to fertility to 14 months after her babies birth, on average. This provides couples with a natural way to parent their infants and space their children.
Sheil Kippley, founder of the Couple to Couple League (along with her husband), wrote the most influential book on ecological breastfeeding, "Breastfeeding and Natural Child Spacing: How Ecological Breastfeeding Spaces Babies." In 1952, breastfeeding had dropped to an all-time low in the US of only 20%. By 1964, La Leche League had published two editions of "The Womanly Art of Breastfeeding," but few medical professionals supported breastfeeding, and few women breastfed at all, let alone exclusively. Published in 1969, Kippley's short (201 page) book describes how ecological breastfeeding is the natural, easy, "ecological" way for a mother to feed and parent her young child, while simultaneously, effortlessly, and naturally providing a natural spacing between babies of 2+ years.
One question I kept in the forefront while reading was how ecological breastfeeding effects traditional societies. It explains why "Irish twins" are seen relatively rarely in families, until formula feeding made serial pregnancy a typical experience. It's interesting to consider how the push for formula feeding coincided with the explosion in married contraceptive use.
I found "Breastfeeding and Natural Child Spacing" to be a fascinating read and a very convincing argument for the wisdom of ecological breastfeeding. I would highly recommend it to anyone interested in NFP, breastfeeding, or natural child birth.