Our data demonstrate a relevant B19-associated risk of fetal death, which is largely confined to maternal B19 infection in the first 20 WG. Timely intrauterine transfusion of fetuses with severe hydrops fetalis reduces the risk of fetal death. Parvovirus B19-associated stillbirth without hydropic presentation is not a common finding.
curred in 19 women and resulted in 17 full-term pregnancies. An increase in the levothyroxine dose was necessary during 17 pregnancies. The mean levothyroxine requirement increased by 47% during the first half of pregnancy. Given the importance of maternal euthyroidism for normal fetal cognitive development, the authors proposed that the women with hypothyroidism increase their levothyroxine dose by approximately 30% as soon as the pregnancy is confirmed. (N Engl J Med 2004;351:241).In some of the children in the study abstracted here, a high maternal TH level may have induced a catabolic state during fetal life leading to decreased birth weight. This may be the first evidence that maternally transferred TH in an euthyroid mother could have a direct toxic effect on fetal development. Maintenance of euthyroidism in a pregnant patient by increasing levels of TH replacement may not be as safe and simple as previously understood.In November 2001, ACOG published a practice bulletin on the clinical management guidelines for thyroid disease in pregnancy. This bulletin clearly outlines the physiological changes in thyroid function during pregnancy to indicate that TSH, free thyroxine (FT4), and free thyroxin index (FTI) do not change in pregnancy. In pregnant patients suspected of being hyperthyroid or hypothyroid, FT4 or FTI should be measured. The goal of management would be to maintain FT4 of the FTI in the high-normal range using the lowest possible dose of medication (Obstet Gynecol 2001;98:883).-RCC)
ABSTRACTBetween one third and two thirds of pregnant women in different parts of the world are susceptible to human parvovirus B19 (B19) infection. Acute infection by B19 during pregnancy has been associated with fetal anemia, hydrops fetalis, nonhydropic intrauterine fetal death, and asymptomatic fetal infection.
Parvovirus B19 is the causative agent of erythema infectiosum in children, but the virus is associated with an increasing range of different diseases. These include acute and chronic arthritis, hydrops fetalis in pregnant women, aplastic anemia, and thrombocytopenia. The host's immune response is directed against the viral structural proteins VP1 and VP2. This study investigated the presence of IgG against the viral nonstructural protein NS1 using Western blot. Serum panels from healthy individuals, B19-infected pregnant women, and various disease groups were tested. The disease groups included patients with symptoms that may be linked to parvovirus B19 infection. The results showed that IgG against the NS1 protein was present in 22% of healthy individuals with past B19 infection. In cases of persistent or prolonged B19 infections, the prevalence of NS1-specific antibodies was as high as 80%. It is concluded that NS1-specific IgG may be used as an indicator of chronic or more severe courses of parvovirus B19 infections.
Parvovirus B19 infection can cause a wide spectrum of disease syndromes. Two cases of parvovirus B19 infection were identified that resulted in life-threatening myocarditis shortly after acute infection in immunocompetent individuals. The diagnosis was made with serological and polymerase chain reaction techniques. One patient was successfully treated by heart transplantation. Sequence analysis showed that the parvovirus B19 cloned from the patients' sera had 99% homology with the prototype sequence. Clinicians should be alerted to the possible role of parvovirus B19 in myocarditis presenting in immunocompetent patients.
At present little is known about the mechanisms influencing the course and severity of parvovirus B19 infection. Antibodies to the parvovirus nonstructural protein NS1 were reported in patients with parvovirus-associated arthritis and those with persisting infection but not in those without complications, suggesting a potential involvement of NS1 or anti-NS1 antibodies in pathogenesis. The immune response to NS1 was examined retrospectively in 33 pregnant women with acute parvovirus B19 infection, 14 of whom experienced symptomatic infection and 19 in whom the infection was subclinical. Antibodies to NS1 were found in 15 (45%) of the women, seven with symptomatic and eight with subclinical infection. No association was found between the development of anti-NS1 antibodies and the occurrence of fetal complications. Of the seven cases in which fetal complications were observed, anti-NS1 antibodies were detected in only three. The finding that an immune response to NS1 can also be demonstrated in patients with asymptomatic infection suggests that anti-NS1 antibodies do not appear to represent a marker for an altered or severe course of infection in pregnant women or to contribute significantly to pathogenesis. Since anti-NS1 antibodies first become detectable at least six weeks postinfection, their presence can be used to exclude acute infection in patients with unclear serology or be used to aid differential diagnosis of rashlike illnesses.
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