Yes, nosebleeds do tend to occur more often during pregnancy. Pregnancy can cause the blood vessels in your nose to expand, and your increased blood supply puts more pressure on those delicate vessels, causing them to rupture more easily. Although it's unpleasant and inconvenient, an occasional minor nosebleed is generally harmless.
The higher the energy of the gamma rays, the thicker the shielding made from the same shielding material is required. Materials for shielding gamma rays are typically measured by the thickness required to reduce the intensity of the gamma rays by one half (the half value layer or HVL).
For example, gamma rays penetrate human bodies with ease, while visible light is scattered or absorbed, and x-rays penetrate our soft tissues but are absorbed by our bones. How far each frequency of radiation can penetrate a given tissue depends on the resonance frequencies of its atoms.