This case series describes full-term pregnancies despite no autonomous ability to breathe due to poliomyelitis or ventilatory insufficiency due to severe kyphoscoliosis. Three women with postpoliomyelitis who were continuously dependent on noninvasive intermittent positive pressure ventilation and one woman who developed ventilatory insufficiency due to severe kyphoscoliosis became pregnant and delivered healthy, full-term babies. They had vital capacities of 240, 250, 280 (5% of normal), and 880 ml (14% of normal), respectively, when becoming pregnant. The up to continuous use of noninvasive intermittent positive pressure ventilation can permit the natural completion of pregnancies of women with little or no ability to breathe unaided.