The significance for maternal and fetal health of gestational obstructive sleep apnea, primary insomnia, restless legs syndrome, and narcolepsy are summarized. The pathophysiology, signs, symptoms, and basic Sleep Medicine concepts that assist the obstetrician in suspecting these 4 conditions are described. Where appropriate, initial management options are also outlined. Referral guidelines to a Sleep Medicine specialist are included when further diagnostic, severity assessment, and management suggestions are needed.