Pregnant women may present with obstetric and nonobstetric conditions (e.g., trauma, appendicitis, cholecystitis, bowel obstruction) whose definitive care cannot be postponed until the postpartum phase. The incidence of nonobstetric operations needed to treat such diseases during pregnancy is estimated at 0.15% to 0.75%. In the last few decades, surgery and surgical care of the pregnant patient have been proven to be feasible and safe, as long as the care team is aware of the special considerations needed in her care. Postoperative care of the pregnant patient presents particular challenges, not only in relationship to the presence of a vulnerable fetus that may get harmed by any of the radiologic tests performed, medications administered, or instruments used in patient care, but also intimately related to the physiologic and anatomic changes encountered in a pregnant woman that puts her, in addition to the fetus, at a different and higher risk profile compared to the nonpregnant woman. The American College of Obstetrics and Gynecologists (ACOG) recommends preoperative obstetrics consultation for any pregnant women undergoing surgery.
In this chapter, we will discuss some of the general strategies needed to take care of the pregnant postoperative patient, with particular emphasis on tips to ensure the safety of both the mother and the fetus. Specifically, we will: (1) briefly delineate the stages of fetal development and explore the maternal anatomic and physiologic changes of pregnancy, (2) suggest systematic physiologic monitoring of the patient and her fetus postoperatively, (3) develop a basic understanding of pain control, medication administration, and transfusion practices in pregnancy, and (4) discuss the safety of different radiologic modalities in pregnancy.
A. Fetal Development
In the first trimester (up to 12 weeks) of pregnancy, the major fetal organs have formed and the uterus is palpable at the level of the symphysis pubis. During the second trimester (13 to 28 weeks), the fetus undergoes growth, and lung maturity is the primary determinant of survival in the case of preterm labor. Growth continues during the third trimester (29-40 weeks). The gestational age of the fetus should be calculated preoperatively. As a general rule, whenever possible, surgery should be performed during the second trimester, when the risk of preterm labor and spontaneous abortion is less likely.
B. Maternal Physiology: The Anatomic and Physiologic Changes of Pregnancy
Pregnancy induces major physiologic changes to the cardiovascular, pulmonary, and hematologic systems, which include, among many, an increase in the cardiac output (CO), a decrease in the functional residual capacity (FRC), dilutional anemia, and hypercoagulability.
A brief summary of the major physiologic and anatomic changes during pregnancy follows, which should be taken into consideration to guide the postoperative care of the pregnant patient. The major physiologic and laboratory changes noted during pregnancy are summarized in Tables 33.1 and 33.2, respectively.
TABLE 33.1 Selected Changes in Clinical Parameters During Pregnancy
Adopted from Tamirisa, Borahay, Kilic. Care in Special Situations: The Pregnant Surgical Patient. Scientific American Surgery; Decker Intellectual Properties Inc., 2015.
TABLE 33.2 Normal Laboratory Values During Pregnancy