Lower levels of prepulse inhibition of startle response in pregnant women compared to postpartum women

Kristiina Kask, Torbjörn Bäckström, Maria Gulinello, Inger Sundström-Poromaa

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


Objective: During the postpartum period, estradiol and progesterone levels decline from very high levels during late pregnancy to low levels within 48 h of parturition. This period is associated with dysphoric states such as the postpartum blues. Animal studies have suggested an enhanced acoustic startle response and deficient prepulse inhibition (PPI) of startle response following progesterone withdrawal and during the postpartum period. The aim of the current study was to compare acoustic startle response and PPI in healthy third trimester pregnant women and healthy postpartum women. Methods: Twenty-eight healthy pregnant and 21 healthy postpartum women (examined between 48 h and 1 week after delivery) were recruited for the study. In addition, to evaluate the time-course of postpartum changes 11 early postpartum women (examined within 48 h following delivery) were included in the study. The eyeblink component of the acoustic startle reflex was assessed using electromyographic measurements of m. Orbicularis Oculi. Twenty pulse-alone trials (115 dB 40 ms broad-band white noise) and 40 prepulse-pulse trials were presented. The prepulse stimuli consisted of a 115 dB 40 ms noise burst preceded at a 100 ms interval by 20 ms prepulses that were 72, 74, 78 or 86 dB. Results: Pregnant women exhibited lower levels of PPI compared to late postpartum women, p<0.05. There was no difference between pregnant women and postpartum women examined within 48 h of delivery. There was no difference in startle response or habituation to startle response between pregnant women and either of the two groups of postpartum women. Conclusion: Healthy women display lower levels of PPI during late pregnancy when estradiol and progesterone levels are high compared to the late postpartum period when ovarian steroid levels have declined.

Original languageEnglish (US)
Pages (from-to)100-107
Number of pages8
Issue number1
StatePublished - Jan 2008


  • Estradiol
  • Postpartum
  • Pregnancy
  • Prepulse inhibition
  • Progesterone
  • Startle response

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology
  • Endocrine and Autonomic Systems
  • Psychiatry and Mental health
  • Biological Psychiatry


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