Infections are increasingly recognized as important contributors of maternal, fetal, and neonatal complications. These can be divided into two major categories: ascending genital tract infections and hematogenously spread infections from the mother. Some infections may be entirely asymptomatic and recognized by antenatal screening. For others, the symptoms can vary significantly and it is not infrequent for some of these entities to be subtle or subclinical. As such, a high index of suspicion is required, along with appropriate knowledge of preventive and therapeutic approaches. Diagnostic tools include serologic testing: markers of inflammation in blood and amniotic fluid and culture of blood, amniotic fluid, placenta, and membranes. Pathologic examination of the placenta, cord, and membranes can be helpful retrospectively.
Human Immunodeficiency Virus
Mother-to-child transmission (MTCT) can occur antenatally, intrapartum, or postpartum through breastfeeding. Most commonly, the infant acquires the infection intrapartum. Without antiretroviral (ARV) therapy, the risk of transmission to the fetus or infant is as high as 25 percent but can decrease to below 2 percent with appropriate management, including antenatal screening, ARV therapy to maximally suppress viral load, and careful selection of the mode of delivery. Labor must be managed in a way to minimize the potential exposure of the fetus to maternal blood. Significant risk factors for MTCT are listed in Table 34-1.
TABLE 34-1:RISK FACTORS FOR MOTHER-TO-CHILD TRANSMISSION OF HIV ||Download (.pdf) TABLE 34-1: RISK FACTORS FOR MOTHER-TO-CHILD TRANSMISSION OF HIV
|High maternal viral load (the amount of HIV RNA in the plasma) |
|Sexually transmitted infections |
|Prolonged rupture of the membranes |
|Young maternal age |
|History of stillbirth |
|Vaginal mode of delivery (in the context of high viral load) |
|Low CD4 count |
|Advanced maternal HIV disease |
|Bleeding during labor (episiotomy, perineal laceration, and intrapartum hemorrhage) |
Canadian guidelines recommend that intrapartum IV zidovudine is offered to all HIV-infected pregnant women, regardless of their antepartum regimen or viral load, to reduce perinatal transmission of HIV (grade III-B recommendation). The UK guidelines suggest offering this only to women with a viral load more than 50 copies/mL
Women who are receiving an antepartum combination ARV drug regimen should continue this regimen on schedule as much as possible during labor and before scheduled cesarean delivery
Women receiving combination regimens that include zidovudine should receive IV zidovudine during labor while other oral ARV components are continued
For women who have either an unknown or a significant viral load (i.e., HIV RNA >50 copies/mL at 34 to 36 weeks) in late pregnancy, delivery by scheduled cesarean delivery is recommended in Canada. This is regardless of the use of antepartum ARV drugs
It is not clear whether cesarean delivery after ruptured membranes ...