The kidney is not one large filter. Each kidney is made up of about a million filtering units called nephrons. Each nephron filters a small amount of blood. The nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process.
Generally speaking, first babies tend to engage from about 34 weeks to 36 weeks. However, some babies only engage once labour starts. Try not to worry, though. Even if your baby hasn't engaged by the time labour starts, in most cases, it's not a problem.
The average man proposes after three years - and the average woman wants him to pop the question four months earlier. Whirlwind romances may not be to everyone's taste, but it seems boyfriends who are approaching their third anniversary are overdue for the ultimate romantic gesture. The average couple gets engaged two years, 11 months and eight days after first setting eyes on each other, according to research. But women feel ready to tie the knot even sooner - after just two years, seven months and 24 days.