Genomic imprinting is one likely candidate, as it allows for phenotypic plasticity and it has already been implicated in maternal‐fetal conflict in the womb via imprinting of maternal and paternal genes in the placenta 36. Despite decades of high vaccination coverage, pertussis has remained endemic and reemerged as a public health problem in many countries in the past 2 decades.

During gestation, the maternal immune system develops a tolerance to the fetus, and suppression of the maternal response is lifted postpartum 99. For example, between 43 and 75% of patients with RA exhibit amelioration of some or all of their RA symptoms during pregnancy (reviewed in 100). Another common technique is to detect variable tandem repeat numbers in mothers versus offspring in microsatellite loci (short tandem repeats) within the Human Leukocute Antigen (HLA) A and B 30, or detecting differences in unshared HLA‐DRB1 alleles 104.Further, in RA patients, symptoms tend to only show improvement during pregnancy, but exacerbation of symptoms postpartum 100. The cooperation and conflict framework that we propose here can help to organize and explain some of the contradictory findings in the literature regarding the effects of fetal cells on maternal health.

Also, consistent with the hypothesis that fetal cells contribute to ongoing maternal somatic maintenance, fetal cells have been identified in many healthy tissues in human mothers 10, 43, 44, 45 and rodent mothers 41, 42, 46, 47. The IgG subclasses when characterized according to the differences in transport capacity gave the following sequence: IgG1 > IgG4 > IgG3 > IgG2.Routine use of whole-cell pertussis (wP) vaccines was suspended in some countries in the 1970s and 1980s because of concerns about adverse effects. Low coverage whole genome sequencing of maternal plasma DNA is already used for sensitive non‐invasive prenatal testing 107, and could additionally be utilized to detect fetal cell microchimerism both during and after pregnancy. In the context of pregnancy, resource conflict has led to the evolution of fetal manipulation of maternal systems to increase resource transfer via the placenta, and the evolution of maternal countermeasures to limit resource flow 3, 4. The ratio of IgG1:IgG2 in the maternal circulation was 2-3 and remained constant throughout pregnancy (17-41 WG).

Not only is she having difficulty with this, for her mother is extremely protective, but she cannot even cut vegetables skillfully. This resource transfer may be mutually beneficially for both maternal and offspring fitness interests, or fetal manipulation may push maternal tissues beyond the maternal optimum 2 leading to conflict over resource allocation.If fetal cell manipulation of the maternal brain induces maternally suboptimal levels of resource transmission to offspring, maternal countermeasures such as immune targeting of fetal cells in the brain might also be expected, which could raise levels of inflammation in the brain. Vaccine effectiveness based on 82 confirmed cases in infants born from Oct 1, 2012, and younger than 3 months at onset was 91% (95% CI 84 to 95). Vaccineren van zwangere vrouwen is een effectieve manier om deze groep te beschermen tegen kinkhoest. Argentina is an example of a middle-income country that has been able to implement a successful strategy for primary prevention through vaccines, making it a health policy.