Before we knew that handwashing could prevent disease transmission, before we could vaccinate, and before we had effective antibiotics, infectious diseases routinely killed entire populations. At the start of the 21st century, we have routine vaccinations and standard precautions to protect us against the risk of infections, and we have medications to treat most infections. We also have antibiotic-resistant bacteria, the threat of pandemic flu, and a variety of other “new” threats to public health.
As infections have changed, so have our testing and treatment protocols for pregnant women. Take the TORCH (toxoplasmosis, other, rubella, cytomegalovirus, and herpes) titer as an example. TORCH titers were originally used to evaluate for the presence of infectious risks during pregnancy, but this panel has fallen into disuse. All of the infections for which TORCH screens can cause fetal injury. Why then do we not screen for evidence of these infections? Are there other infections we should be screening for on a routine basis?
Toxoplasmosis has limited routes of transmission. The incidence of toxoplasmosis infection in the United States is declining, and the risk to the fetus occurs only when the mother has a primary infection during pregnancy. Women who were previously exposed and who have positive immunoglobulin G (IgG) titers to Toxoplasmosis gondii will not transmit the infection to a fetus if exposed during pregnancy. Approximately 38% of pregnant women in the United States have evidence of previous infection; congenital toxoplasmosis occurs in 1 in 10,000 live births.1 Because the incidence is so low, prevention counseling is more useful and more cost-effective.2
The O in TORCH stands for “other.” In addition to toxoplasmosis, rubella, cytomegalovirus (CMV), and herpes, individual institutions have sometimes added a fifth test in place of the “o.” This was usually a serology test for syphilis, but could also be parvovirus, hepatitis B, varicella-zoster virus, or Epstein–Barr virus. Today, a blood test for syphilis is recommended for all women during the initial prenatal exam. None of the other diseases on the list merit routine screening. In the absence of documented exposure, the cost and potential benefit do not fit the criteria for a screening test.
Rubella screening is one of the routine laboratory tests ordered during the initial prenatal visit. Because vaccine rates are high in the United States, we are close to having “herd immunity” to rubella; the scenario of a nonimmune woman being exposed to someone with active infection is unlikely. The article in this issue by Barbara Hackley, CNM, MSN, describes this phenomenon well.3
Testing for CMV (the C in TORCH) infection is complex.4 CMV is common among young children, and the incidence of primary infection during pregnancy is low. In addition, most primary infections are asymptomatic. Normally the presence of anti-CMV–specific IgG indicates immunity, but reinfection with a new strain of this virus is possible despite detectable IgG levels. IgM levels can remain high for months and are not always helpful in determining the presence or absence of acute infection. Pregnant women with a known exposure need parallel testing (i.e., saving the original blood drawn and testing it with another sample that is drawn 3–4 weeks later). Although parallel testing can confirm infection, time limits its utility for obstetric decision-making.
Serologic herpes testing needs to be performed as type-specific antibody testing, which confirms previous exposure.5 During pregnancy, the greatest risk to the fetus comes with primary infections late in gestation. There is no evidence that treating seronegative women prophylactically decreases neonatal infection, and there is limited evidence that the use of antiviral therapy by women who are seropositive has resulted in lower neonatal infection rates.6
In contrast, some tests that will protect women and infants are slow to gain acceptance. Providers who believe that their patients are not at risk often reject offering routine HIV testing. However, in more than 20 states, the incidence of HIV is high enough that the Centers for Disease Control and Prevention recommends testing all women twice during pregnancy to prevent perinatal transmission.7
Changes in the guidelines for the treatment of common infections are another example of the need to maintain current knowledge. Effective antibiotic choices are important not only for the women we care for today, but also for those who will be harmed if antibiotic resistance continues to increase. Prescribing antibiotics when they are not warranted, treating with a broader spectrum antibiotic than is needed, prescribing more days of therapy than are necessary, and treating with the wrong antibiotic all contribute to future resistance. For example, urinary tract infections caused by Escherichia coli now have resistance to ampicillin in more than 35% of specimens and to sulfamethoxazole and trimethoprim in more than 15% of specimens.8 Add resistant E coli to methicillin-resistant Staphylococcus aureus, extensively drug-resistant tuberculosis, and vancomy cin-resistant enterococci, and the sum is an increasing risk from bacteria we “know” how to control. Everyday management decisions become more complicated as new pathogens and evidence emerge to challenge our ingrained practice patterns.
It has been an honor and a pleasure to share in the creation of this issue of the Journal of Midwifery & Women's Health. As this issue of JMWH came together, we intended to emphasize key issues across the spectrum of infectious disease, both in the United States and on a global level. From postoperative infections to human papillomavirus to listeria, midwives have responsibility for counseling, vaccinating, testing, diagnosing, and treating women. We work with a world's worth of infections that confront us with their risks. Infectious diseases are among the most common conditions midwives see and treat. We each have an obligation to maintain our familiarity with an ever-broadening array of information and changing recommendations. It is our hope that this issue will contribute to that goal.