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.
Updated October 06, 2016. The best time to get pregnant is the two to three days right before ovulation. Yes, you must have sex before you ovulate -- not after! While these three days are your most fertile, you're also able to get pregnant if you have sex up to five days before you ovulate. So, basically, you've got one week every month when sex can lead to pregnancy. Your high school sex ed teacher lied to you.