"has demonstrated expertise in the diagnosis and management of clinical conditions that occur during sleep, that disturb sleep, or that are affected by disturbances in the wake-sleep cycle. This specialist is skilled in the analysis and interpretation of comprehensive polysomnography, and well-versed in emerging research and management of a sleep laboratory."[51]
^ Hirshkowitz, Max (2004). "Chapter 10, Neuropsychiatric Aspects of Sleep and Sleep Disorders (pp 315-340)" (Google Books preview includes entire chapter 10). In Stuart C. Yudofsky; Robert E. Hales (eds.). Essentials of neuropsychiatry and clinical neurosciences (4 ed.). Arlington, Virginia, USA: American Psychiatric Publishing. ISBN 978-1-58562-005-0. ...insomnia is a symptom. It is neither a disease nor a specific condition. (from p. 322)

Fatigue during the first trimester of pregnancy is likely caused by changing levels of hormones, such as progesterone. Toward the end of pregnancy, some women find it difficult to sleep because of the uncomfortable size of their abdomen. Some women are too excited, anxious, or worried about becoming mothers to sleep well. Other women who are pregnant complain that vivid dreams prevent them from getting restful sleep. Sleep apnea, especially if it's severe and causes your blood oxygen level to drop during sleep, is a risk to the fetus.

Keep a pen and paper next to your bed. If you're often kept awake by racing thoughts and worries and you tend to make to-do lists in your head, keep a pen or pencil and a small pad of paper handy and write them down. As you put each item down on paper, imagine yourself setting aside that concern. (Again, use a book light; don't turn on the overhead or a bright bedside light to write.)