Perinatal infections are those infections affecting the mother during a pregnancy, and may be transmitted to the fetus during pregnancy, during delivery through the birth canal, or after delivery through the breast milk.
Description
Perinatal infections may be bacterial, fungal, or viral in nature. The degree to which the mother is affected by the infection is not an indication of its impact on the fetus. The mother may have slight or no symptoms, and yet the fetus may be significantly affected by the infection. The woman's sexual partner(s) may also be affected by these infections and should seek medical treatment. The more common perinatal infections significantly affecting the fetus are discussed below.
Chlamydia
When a woman has multiple partners, the use of condoms every time a woman has sexual intercourse can decrease the risk of becoming infected. Limiting the number of sexual partners also decreases the risk of chlamydial infection.
Cytomegalovirus (CMV)
CMV is a common congenital viral infection, belonging to the herpes virus group of infections. Maternal infection usually occurs through sexual intercourse, including kissing, with an infected individual. Maternal infection may be asymptomatic, or the mother may present with mononucleosis-like symptoms, fatigue, lymphadenopathy, or fever. Transmission to the fetus can occur if the mother becomes infected during pregnancy, or if she has a flaring of a pre-exisisting CMV infection. Some immunity is transferred to the fetus if the mother has had a prior CMV infection. Infants infected in utero with CMV may be asymptomatic, or may have a delayed reaction, manifesting as mental retardation or deafness. About 10% of newborns with congenital CMV have evidence of disease at birth. CMV can also be acquired by the newborn through cervical secretions, saliva, urine, or breast milk. It can also be acquired in the newborn nursery by contact with infected individuals. Individuals with a compromised immune system, organ recipients, and those with HIV/AIDS are more likely to suffer severe consequences.
Genital herpes
Cesarean delivery can substantially reduce disease transmission to the neonate. For mothers with genital herpes, delivery following premature rupture of membranes (PROM) should be considered, as the risk of disease transmission increases by six hours after PROM. If maternal HSV is suspected, a fetal scalp monitor should be avoided, as this creates a direct portal of entry for the infection.
Hepatitis B virus (HBV)
HBV is contracted through direct contact with the blood or other body fluids of an infected individual. It is sexually transmitted, through infected blood or blood products, and to the infant during a vaginal birth. In infants with HBV, 90% contract it at birth. The disease may present in very mild form, with no symptoms and only detected through liver function tests, or may be severe, even fatal, if it has advanced to liver necrosis. Symptoms of HBV infection include:
fever that is usually either not present, or very mild
vague abdominal discomfort
abdominal pain
loss of appetite
nausea
vomiting
joint pain
Human immunodeficiency virus (HIV)
In the early 1990s, studies of ZDV used during pregnancy and given to the neonate for six weeks postpartum resulted in a 70% decrease in maternal HIV transmission to the infant. Cesarean birth also reduces transmission, as compared with vaginal birth. Knowledge of the mother's HIV status during pregnancy is therefore important in reducing the transmission risk. Testing for HIV status should be offered to all pregnant women. Avoidance of breast-feeding can also decrease the risk of transmission. If untreated, about 20% to 30% of infants born to HIV-positive women will be infected. Treatment with ZDV and avoidance of breast-feeding has been reported to lower transmission to about 2% to 3%. In 1999, a Ugandan study reported that a single dose of nevirapine given to infected mothers during labor in addition to a single dose given to the neonate within three days of birth cut the transmission rate in half, as compared with those treated with AZT throughout pregnancy and during the first six weeks of life.
Human papillomavirus (HPV)
HPV is a STD than can cause genital warts. However, many infected individuals are asymptomatic. This variability is due to the fact that there are about 30 types of HPV. The CDC estimates about 5.5 million new cases of HPV a year, with about 20 million people infected to date. About 28–46% of women under the age of 25 have HPV. Individuals who are immunocompromised, such as those with HIV, are at higher risk of contracting the disease. This is also true of those who are pregnant. Genital warts appear to grow more quickly during pregnancy, and can be large enough to obstruct the cervix for a vaginal delivery. Disruption to the warts of the genital tract during pregnancy or delivery can lead to significant maternal blood loss.
Rubella
Women in childbearing age should have a titer draw to test for immune status. If they have not been exposed to rubella, they can be vaccinated against the disease, but should not become pregnant for three months following the vaccination, due to potential devastating effects on the fetus.
Streptococcus
Prevention of transmission of GBS from the mother to the infant can be enhanced by careful monitoring of the mother during labor for potential signs of infection such as fever, urinary tract infection, or PROM before 37 weeks or 18 hours or more before delivery. Treating the mother with IV antibiotics during labor limits the risk of transmission.
Syphilis
Use of a latex condom can reduce the risk of contracting the disease. However, the condom may not cover the area of infection. A blood test is the best way of finding out if one has syphilis, as the sores may be in hidden areas.
Toxoplasmosis
Prevention of infection through cat feces is best done by having someone other than the mother clean the cat litter, and to avoid inhalation of airborne oocytes. If this is not possible, cat litter should be changed daily, as spores develop in one to five days in the litter. Cats become infected by eating contaminated wildlife, so keeping the cat completely indoors significantly reduces the risk of contagion. Infection through meat can be avoided by avoiding raw meat and by cooking meat to at least 159°F (71°C). Garden soil can be contaminated, so the use of gloves when gardening with thorough hand washing afterwards can decrease infection. Outdoor sandboxes should be covered to avoid contamination by stray cats.
Cytomegalovirus
CMV can be shed in body fluids, so care must be taken when handling these substances. This includes the handling of diapers, especially in day care environments. Those working in a hospital environment should always observe universal precautions when handling any body fluid or secretion. Careful hand washing can decrease the risk of transmission. Since CMV is shed in cervical secretions, cesarean birth may decrease the risk of transmission, although infection during the first two trimesters of pregnancy carries the greatest fetal risk. Research is investigating the usefulness of a preconception vaccine.
Hepatitis B
The HBV vaccine is considered the best prevention. It is a series of three injections over seven months. It is not contraindicated in pregnancy. Use of latex condoms will help reduce the risk of transmission. Avoiding high-risk contact, such as contact with blood and other body fluids, will also lessen the risk of HBV. The CDC recommends that newborns born to HBV-infected mothers receive hepatitis B immune globulin after birth as well as the first dose of the vaccine within 12 hours postpartum.
Human papillomavirus
Use of a condom and limiting the number of sexual partners decreases the risk of contracting the disease.
Health care team roles
Laboratory technicians and phlebotomists need to observe standard universal precautions in drawing and handling blood and other body fluids, as the complete infection status of a patient will not be known. This includes the use of gloves, eye protection such as a face-mask or goggles, and personal protective clothing. Radiology technicians will be involved in ultrasound scanning to detect fetal compromise as a result of infection. Ultrasound-guided sampling of amniotic fluid or fetal tissue may be used to diagnose fetal infection. Through individual discussion, waiting room videos, and pamphlets, nurses can educate pregnant mothers during routine visits about ways to prevent infection by these agents. Nurses can play a significant role in emphasizing the need for retesting after treatment (when required) and discussing the importance of having the woman's sexual partner tested and treated to avoid reinfection.
KEY TERMS
Lymphadenopathy—A disorder affecting the lymph nodes or lymphatic vessels.
Perinatal—The time during pregnancy, delivery, and until about one month postpartum.
Teratogenic—Tending to produce irregularities of formation.
Vertical transmission—The transmission of a disease or condition from one generation to the next, either through genetics, through the uterine environment, or through the breast milk.
BOOKS
Burrow, Gerard N., and Thomas P. Duffy. Medical Complications during Pregnancy, 5th Edition. Philadelphia: W. B. Saunders Company, 1999.
Chin, James, ed. Control of Communicable Diseases Manual. Washington, DC: American Public Health Association, 2000.
Scott, James. Danforth's Obstetrics and Gynecology, 8th ed. Philadelphia: Lippincott Williams & Wilkins, 1999.
