One way to observe prenatal development is via ultrasound images. Modern 3D ultrasound images provide greater detail for prenatal diagnosis than the older 2D ultrasound technology. While 3D is popular with parents desiring a prenatal photograph as a keepsake, there are no definitive studies linking ultrasound to any adverse medical effects. The following 3D ultrasound images were taken at different stages of pregnancy.
The common cold is the most frequent infectious disease in humans with the average adult contracting two to four infections a year and the average child contracting between 6–12. Collectively, colds, influenza, and other infections with similar symptoms are included in the diagnosis of influenza-like illness. They may also be termed upper respiratory tract infections
