In the Puerperium, Primiparae Exhibit Higher Levels of Anxiety and Serum Peptidase Activity and Greater Immune Responses Than Multiparae

Background: Delivery is accompanied by increases in anxiety levels that are significantly related to an activation of the inflammatory response system (IRS), as indicated by increases in the serum concentrations of interleukin-6 and the interleukin-1 receptor antagonist (IL-1RA) and increases in the activity of prolyl
endopeptidase (PEP), a cytosolic endopeptidase that cleaves peptide bonds on the carboxyl side of proline in behaviorally active neuropeptides involved in anxiety. Primiparae may show an immune responsivity differing from that in multiparae. The aims of this study were to examine whether there are differences in anxiety levels, the IRS, and serum PEP values between primiparae and multiparae before and after delivery.

Method: We administered the Spielberger State-Trait Anxiety Inventory (STAI) to and assessed serum IL-1RA and soluble CD8 (sCD8) concentrations and serum PEP activity in 48 primiparae and 48 multiparae at the end of term and 1 and 3 days after delivery. Data were gathered in 1996 and 1997.

Results: We found that in primiparae (p = .001), but not in multiparae (p = .6), there was a significant increase in the STAI score 3 days after delivery and that primiparae had significantly higher STAI scores than multiparae 3 days after delivery (p = .01). Primiparae showed significantly higher serum IL-1RA levels than multiparae 1 (p = .003) and 3 (p = .02) days after delivery, but not before delivery. Primiparae also had lower serum sCD8 and higher serum PEP activity than multiparae before and after delivery.

Conclusions: The results suggest that primiparae suffer greater anxiety and have a different neuroimmune responsivity than multiparae and that the increased anxiety levels in primiparae may be related to changes in the IRS and serum PEP activity.