Parvovirus B19 And Pregnancy

Something pregnant women should be aware of discussed here, abstract: 

Several infections in adults warrant special consideration in pregnant women given the potential fetal consequences. Among these is parvovirus B19 deserves special attention since the harmful effects on the pregnant woman and fetus. It can then cause fetal anemia, non-immune fetal hydrops and fetal death. Among cases with fetal demise, B19 is found in significant numbers, especially in the second and third trimesters of pregnancy. There is no specific treatment or prophylaxis available against B19 infection, but counseling of non-immune mothers and active monitoring of confirmed maternal infections with intervention to correct fetal anemia is likely to decrease mortality.

This may be something that pregnant women should discuss with their physician, if they want to monitor teir status in this regard.

Autism and maternal infections during pregnancy

There is epidemiological evidence that viral infections during pregnancy associate with higher frequency of autism in children. Recently, experimental data on this association were published in Science.

The phenomenon underlying the correlation is known as maternal immune activation. In experimental models (mice), the maternal immune activation increases the levels of a molecule, interleukin-17a, which affects the fetal brain development. Based upon these results, the authors of the study have proposed that targeting cells involved in the maternal immune response (i.e., the T helper 17 cells) may reduce the risk of having children with inflammation-associated autism.

Two years ago, another publication associated maternal infections during pregnancy not only with autism, but also with schizophrenia. In addition, the authors discussed clinical data that infections in pregnancy may increase the risk of epilepsy, cerebral palsy, Alzheimer and Parkinson diseases in the offspring.

What does this mean for pregnant women? Does it mean that it is better for future moms to not work, and limit their exposure to environments/settings where they can easily contract infectious diseases? This discussion is still missing from the publications. Another unanswered question is whether the increased rates of autism in the past years is due to the increased employment of women (see statistics in the graph below)

By Rcragun (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons

Many likely causes for the increased rates of autism have been discussed, such as the increased awareness of the condition (and therefore, its more frequent diagnosis), television, chemicals, vaccines, older age of the parents.  However, we need to consider additional factors, including the phenomenon of maternal immune activation and its effects on the fetal development of the central nervous system.
 
There are several historic phases, during which women have increased their representation in the workforce, and the fourth phase (from the late 70s to present days) coincides with the increased rates of diagnosed autism.  

Association/correlation does not mean causation; however, it might be prudent to protect pregnant women by offering  better work conditions – shorter workdays, days working from home, and a longer paid maternity leave that starts months before the due date.