Pregnancy and breastfeeding have no long-term deleterious effects on bone, shows a study in 4,681 postmenopausal women aged 50–94 years. Using Cox's proportional hazard models, the researchers of the Tromsø study found that breastfeeding could even contribute to a reduced risk of hip fracture after menopause. Compared with women who did not breastfeed after birth (n = 184), those who breastfed (n = 3,564) had a 50% reduced risk of hip fracture.