Preterm labor and delivery is defined as birth before the 37th week or term weight of an infant as more than 2 standard deviations below the mean (small for gestational age). Such infants account for 8% to 10% of all births and nearly 80% of early neonatal deaths in the United States.

1. Several problems are likely to develop in preterm infants (Table 40-12: Problems Associated with Prematurity).
2. β₂-Agonists (ritodrine, terbutaline) used to inhibit labor may interact with anesthetic drugs or produce undesirable changes before induction of anesthesia (Table 40-13: Side Effects of beta_2-Agonists Administered to Stop Premature Labor).
   1. Delay of anesthesia for at least 3 hours after the cessation of tocolysis allows β-mimetic effects of β ₂-agonists to dissipate; potassium supplementation is not necessary.
   2. Preterm infants are more sensitive to the depressant effects of anesthetic drugs. Regardless of the technique or drugs selected, the most important goal is prevention of asphyxia of the fetus.

Obstetrical Anesthesia

1. Physiologic Changes of Pregnancy
2. Placental Transfer and Fetal Exposure to Anesthetic Drugs
3. Anesthesia for Labor and Vaginal Delivery
4. Anesthesia for Cesarean Delivery
5. Anesthetic Complications
6. Management of High-Risk Parturients
7. Preterm Delivery
8. Human Immunodeficiency Virus and Acquired Immunodeficiency Syndrome
9. Substance Abuse
10. Fetal Monitoring
11. Newborn Resuscitation in the Delivery Room
12. Anesthesia for Nonobstetric Surgery in Pregnant Women