Primipaternity and birth interval; independent risk factors for preeclampsia.

BACKGROUND: The exact cause of preeclampsia remains unknown. The past decade has seen an ongoing debate on the relative importance of primipaternity versus prolonged birth/pregnancy interval.

AIMS: The aim of the current study was to analyze these two major potential risk factors in a high risk population in the Northern suburbs of Adelaide; a socioeconomically disadvantaged area characterized by instable relationships and overall poor health and lifestyle.

METHODS: A retrospective cohort study was performed on all multigravid women birthing at the Lyell McEwin Hospital, Adelaide, from July 2011 to August 2012; 2003 patients were included in this analysis. Basic demographic data, previous pregnancy outcomes, paternity, and birth and pregnancy intervals were recorded.

RESULTS: Women with a previously normal pregnancy had a significantly increased risk of developing preeclampsia in subsequent pregnancy with a new paternity (OR: 2.27 [p = .015]). Increasing birth and pregnancy intervals were associated with a significantly increased risk of developing preeclampsia in later pregnancies, with OR 1.39 at 3 years (p = .042) and OR 2.05 at 4 years (p = .002).

CONCLUSIONS: The results of this study indicate that both prolonged birth interval and primipaternity are independent risk factors for preeclampsia in multigravidae.