Pregnancy- and lactation-associated osteoporosis (PLO) is a special form of osteoporosis, which is the result of multiple factors affecting bone metabolism. The manifestations of PLO include severe low back or hip pain in the third trimester of pregnancy and postpartum period, and some patients present with a decrease in height and even fragility fractures. We report here a 33-year-old patient who presented with a left intertrochanteric fracture after falling from standing height at 10 months postpartum. She was diagnosed with PLO because of a considerable decrease in bone mineral density. Our findings are discussed in relation to the literature. Early diagnosis and timely and appropriate therapy are particularly important for PLO. PLO should be considered in patients who complain of low back or transient hip pain during pregnancy and lactation. Discontinuing breastfeeding and supplementing calcium/vitamin D should be recommended after diagnosis of PLO is established.