Effect of Pregnancy Interval on Second Pregnancy Blood Pressure Following Prior Preeclampsia.

Objective: Preeclampsia generally occurs in first pregnancies and tends not to recur when the interpregnancy interval (IPI) is short. We hypothesized that, in women experiencing preeclampsia in their first pregnancy, the difference in mean arterial pressure (MAP) across pregnancy between their index and subsequent pregnancy would be inversely associated with the length of time between pregnancies and that the interval between pregnancies will be directly associated with the likelihood of preeclampsia recurrence.

Methods: This was a retrospective chart review evaluating 171 women diagnosed with preeclampsia during their first pregnancy who had a subsequent pregnancy at our institution. Blood pressures were collected from each pregnancy, marking the recurrence of hypertensive disorders, including preeclampsia. Antepartum MAP was compared between pregnancies, examining differences as a function of IPI.

Results: There was a significant association of IPI with the reduction in MAP between pregnancies across trimesters ( P = .04), but this reduction became smaller over time. The MAP during the third trimester decreased significantly between pregnancies across all patient groups (IPI <24 months: -5.7 mm Hg, P < .0001; IPI 24-48 months: -4.5 mm Hg, P < .0001; IPI >48 months -3.4 mm Hg, P = .03). The recurrence rate of preeclampsia did not vary significantly with IPI ( P = .21).

Conclusion: The IPI influences the MAP of the second pregnancy in women with prior preeclampsia. Shorter IPI is associated with a greater reduction in MAP when compared to the longer IPI. Although there was a trend toward higher preeclampsia recurrence with longer IPI, this trend did not reach statistical significance.