Exposure to raised levels of the pesticide DDE (now banned in the US, Europe and several other countries) were associated with shorter durations of lactation in the US.

A study involving 229 women living in an agricultural town in northern Mexico found that the women with the highest blood DDE levels when they gave birth were able to lactate on average three months, compared to 7½ months by the women with the lowest levels. The discrepancy only applied to the women who had lactated previously, not to first-time mums.