Be aware of labor and delivery complications
Resistant bacteria emerging
Hospital pharmacists who are aware of the conditions and complications requiring drug therapy during labor and delivery will be able to make knowledgeable decisions about the rapid accessibility of critical medications in the labor and delivery unit, researchers advise.
Research conducted by Gerald Briggs, B.Pharm., and Stephanie Wan, PharmD., pharmacist clinical specialists at Women's Pavilion, Miller Children's Hospital, Long Beach (CA) Memorial Medical Center, looked at the drug therapy of common conditions and complications during labor and delivery and the fetal and neonatal effects of the therapy. They say the pharmacologic therapy of common conditions occurring in labor and delivery primarily involves oxytocin and prostaglandins for cervical ripening and labor induction and systemic and regional narcotic analgesics for pain.
"Because most medications used in women during labor and delivery do not have FDA-approved labeling," they say, "pharmacists should understand the benefits and limitations of medications used in the mother. Although induction and augmentation of labor and the control of pain often require drug therapy, other, less frequent, complications may occur in labor. Drug therapies for these complications include anti-infective agents to treat maternal infection and prevent neonatal diseases; antiretrovirals to reduce perinatal HIV-1 transmission from the mother to the fetus; corticosterioids to prevent fetal lung immaturity; antihypertensives to treat preeclampsia; anticonvulsants to treat eclampsia; tocolytics for premature labor; and oxytocin, ergot alkaloids, and prostaglandin analogues for postpartum hemorrhage. The fetal and neonatal effects of therapy for the conditions that occur during labor and delivery are usually benign, but significant morbidity and mortality involving the mother, the fetus, and the newborn are ever-present."While medications routinely used in a labor-delivery unit are a small fraction of those used in some other patient care areas of a hospital, such as the intensive care or general medical units, a unique characteristic of drug therapy during labor is that treatment intended for one patient (the mother or fetus) also exposes a second patient (mother or fetus). Although maternal status is usually the primary focus of drug administration, it must also focus on the fetus and the risk of developmental toxicity. The components of developmental toxicity, they say, are fetal growth restriction, structural defects, functional and behavioral deficits, and embryonic or fetal death. Neither growth restriction nor structural defects are a concern with drug therapy used during labor and delivery because those toxicities occur after prolonged therapy or exposure earlier in pregnancy, respectively. In contrast, fetal functional or behavioral deficits and death are of greater concern when treating a patient in labor.
Examples of functional or behavioral deficits they cite are blood dyscrasia, renal impairment, premature closure of the ductus arteriosus, respiratory depression, lethargy, irritability, and depressed attention and social responsiveness. Fetal death may occur, they say, if placental perfusion is jeopardized, such as in drug-induced maternal hypotension.
The researchers say antibiotic agents are administered during the intrapartum period to prevent and treat maternal infection and to prevent neonatal disease. Short courses of antibiotics are used during the pregnancy puerperium to prevent such infections as group B streptrococci in newborns, procedure-related bacterial endocarditis, and postpartum endometritis and to treat chorioamnionitis. Selection of the appropriate agent requires consideration of several factors, they say, including the potential pathogens, emergence of resistant organisms, risks associated with drug exposure to the fetus and the individual maternal risk stratification. Also to be considered are the appropriateness of regimens for those with a history of anaphylactic or allergic reactions to antibiotics. Proper antibiotic dosage selection requires knowledge of the physiological changes in pregnant women that may result in altered pharmacokinetics in pregnancy.
Selection of antibiotics is often empirical, with the appropriate regimen targeted against most potential pathogens. While short courses of antibiotics are typically used, emergence of resistant strains of bacteria is becoming an ever-increasing problem, particularly among hospitalized patients, the researchers say several studies have demonstrated postoperative colonization of resistant skin flora in patients given antimicrobial prophylaxis, with evidence existing for both selections of resistant organisms from the preoperative flora and from the nosocomial environment. In addition, treatment of group B streptococci in penicillin-allergic patients has been complicated by increasing resistance to clindamycin and erythromycin.
The presence of resistant organisms in the neonate has also been reported with the increasing maternal administration of antibiotics during labor and delivery to reduce neonatal group B streptococci disease and to decrease neonatal morbidity associated with premature rupture of membranes.
[Editor's note: Contact Mr. Briggs at [email protected].]
Reference
- Briggs, GG, Wan SR. Drug Therapy During Labor and Delivery, Part I and II. American Journal of Health-System Pharmacy. 2006;63(11); 1038-1047 and American Journal of Health-System Pharmacy, 2006;63(12);1131-1139.
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