Vector Borne Zoonotic Dis. 2011 Jul;11(7):891-8. Epub 2010 Oct 6.
Borreliosis during pregnancy: a risk for the unborn child?
Source: Division of Infectious Diseases in Gynaecology and Obstetrics, 1st Department of Obstetrics and Gynaecology, Ludwig-Maximilians-University Munich , Munich, Germany .
Little is known regarding the possible harmful effects of Borrelia infections in pregnancy, since such a risk analysis is difficult to perform.
Transplacental transmission of Borrelia burgdorferi has been documented in several animal studies. Therefore, it had been thought that fetal infection and teratogenicity was possible from B. burgdorferi, especially considering the similarities between Lyme borreliosis and syphilis.
However, several clinical, serological, and epidemiological studies have failed to confirm a causal association between B. burgdorferi infection and a pregnancy adverse outcome. Moreover, there have been no reported cases of transmission of Borrelia via breast milk.
However, the therapeutic approach to pregnant women with Lyme disease should be antibiotic treatment, according to the clinical manifestation and the timing of the tick bite.
An effective vaccine is not yet available and the prevention of Lyme borreliosis depends on public and physician education, and appropriate antibiotic therapy during pregnancy.
PMID: 20925520 [PubMed - in process]
VECTOR-BORNE AND ZOONOTIC DISEASES
Volume 11, Number 7, 2011.
Borreliosis During Pregnancy: A Risk for the Unborn Child?
Ioannis Mylonas, Division of Infectious Diseases in Gynaecology and Obstetrics, Ludwig-Maximilians-University Munich, Munich, Germany.
Little is known about the possible harmful effects of Borrelia infections in pregnancy, since such a risk analysis is difficult to perform. Transplacental transmission of B. burgdorferi has been documented in several animal studies. Therefore, it has been believed that fetal infection and possible teratogenicity could arise from B. burgdorferi, especially considering the similarities between Lyme borreliosis and syphilis.
The likelihood of a transplacental infection is probably higher at the beginning of pregnancy than in the remaining duration of pregnancy. Besides abortion, malformations such as syndactyly, ventricular septum defect, and heart rate defects have been described. However, some case reports of pregnant women with erythema migrans or neurological involvement were reported without any association between infection and adverse pregnancy outcome.
Several studies have looked at the connection between seropositivity during pregnancy and fetal malformation and adverse pregnancy outcome. A slightly elevated seropositivity (6%) was detected for spontaneous early abortions in 49 women in an Italian Borrelia-endemic area, in comparison to control groups. In another study, 421 serum specimens obtained from cord blood did not show an association between the presence of immunoglobulin G (IgG) antibodies to B. burgdorferi and congenital malformations. In 1416 pregnant women, of which 12 (0.85%) were seropositive, no increased risk of malformation could be demonstrated. Another clinical and serological study was performed where 2000 women were examined at the first prenatal visit and again at delivery. Eleven women (0.7%) were seropositive and 79 (4%) had reported Lyme disease in the past. No association between exposure of the mother to B. burgdorferi either before conception or during pregnancy could be made with adverse pregnancy outcome or congenital malformations. Yet another study, which compared 5000 infants in an endemic area to a control group, showed no significant difference in the incidence of congenital malformation.
Since there have been no reported cases of transmission of Borrelia via breast milk, the risk of this cannot be assessed. While it is noteworthy that it was possible to obtain Borrelia DNA via PCR from two lactating mothers, it is unclear whether this indicated that intact bacteria or fragments of the bacterial genome were present. Due to the lack of data on this topic, a contraindication to lactation has been established. A recommendation for this may be especially prudent, as Treponema transmission through such a pathway is entirely possible. However, it must be noted that the transmission of Treponema through mucous membranes such as occurs in genital and oral sex has not been seen in Borrelia infection in humans or in animal experiments.
In general, an acute infection is considered to entail a higher risk during pregnancy for fetal transmission than does a chronic infection, as the mother already has IgG antibodies against the pathogen.
The results of clinical, serological, and epidemiological studies have not confirmed a causal association between B. burgdorferi infection and adverse outcomes.