It's actually interesting that someone would ask this question. When I became pregnant with the child I am currently carrying, I am 28 weeks. I had go on a progesterone replacement, because I wasn't producing enough. They asked me all sorts of questions, to make sure I was expecting. I guess one needs progesterone to have a healthy pregnancy. Some people take this drug as a menoposal drug and some take the drug for fertility issues. Well I got the perscription home and reading the side effects; it said possible side effects that may occur are sleepiness or tiredness, dizziness, cough, nausea, vomiting, cramps...worry, irritability, headache, mental or mood changes (such as depression, memory loss, or confusion)...etc. Anyhow all of the side effects sounded like just plain being pregnant. So, I took the liberty to ask my doctor and look up acurate information about this subject. One of the resources, a medical site, I cant remember the site, I am pregnant, I came across said all these emotional, irritability, forgetfulness, is normal. It also increases as the months of pregnancy go on, because the placenta produces more and more progesterone as the baby grows. They said that for some reason the hormones during pregnancy shrink brain cells. They don't know why it happens. They also said that if one doesn't get enough sleep the effects are enhanced. In addition, the effects on every women are different and every pregnancy we have we could act differently. After we have the baby, our bodies go through a withdrawl of the hormones, so some women actually end up feeling depressed, which is called post partom depression. After a certain amount of time, our brain cells go back to normal, its usually after we get enough sleep. I thought it was an interesting topic, because I too am forgeting everything, moody, tired all the time. So, I am able to tell everyone it's normal. Good Luck and pass it on. If I find the web site I will send to you.