The accumulation of pleural fluid during labour
Objectives: Labour appears to promote the development of pleural effusion. The presence of pleural fluid at the end of normal pregnancy and after an uncomplicated labour was investigated using thoracic ultrasonography. Design: Fifty-two women, 20 pregnant and 32 postpartum of similar age were examined, both supine and seated via an intercostal approach, less than 8 h before delivery for the pregnant and less than 24 h after delivery for postpartum women. Results: Eight of the 32 postpartum and only 2 of the 20 pre-partum women had pleural effusion. Three postpartum and none pre-partum women had moderate (2-3 cm depth) pleural effusion. One out of 2 and 1 out of 8 women with effusion before and after delivery respectively had twins. No association was found between the development of pleural effusion and age, weight-gain during pregnancy, use of oxytocin or intravenous fluid, weight of newborn and smoking habits during pregnancy. Conclusions: Normal labour rather than pregnancy, seems to be the main factor associated with asymptomatic pleural effusion. Repeated Valsalva manoevres which increase intrathoracic pressure and impair lymphatic drainage could be an explanation.