What biological changes does pregnancy induce in the mother?

To view our published paper, click on the reference below:
Mittal A, Pachter L, Nelson JL, Kjærgaard H, Smed MK, Gildengorin VL, Zoffmann V, Hetland ML, Jewell NP, Olsen J, Jawaheer D. Pregnancy-induced changes in systemic gene expression among healthy women and women with rheumatoid arthritis. PLoS One. 2015 Dec 18;10(12): e0145204. doi: 10.1371/journal.pone.0145204.

Summary of findings

Background: It is clear that pregnancy induces major biological changes in the mother (healthy or with RA). However, what these changes are is not understood as there has not been much research on this topic. We have performed a pilot study to identify changes induced by pregnancy (compared to pre-pregnancy).

Results: By examining genes and their behaviour (how much they are switched on or off) before and during pregnancy in healthy women and women with RA, we found many changes in the mother's blood, with a few differences between the RA and healthy women. Many of these became more intense as pregnancy progressed to the third trimester. These also included changes in the immune system, which was very interesting because it is generally believed that the maternal immune system is not very active during pregnancy in order to protect the foetus. Instead, our results show that the maternal immune system (in the blood) is very active during pregnancy. [Other researchers have shown that the immune system is suppressed only in the area around the foetus].

Conclusions: Our results in this paper help us understand what "normal pregnancy-related changes" (immune-related and others) occur in the mother's blood during pregnancy. They provide evidence that the maternal immune system plays an active role during pregnancy, and show that there are some differences in RA pregnancy.