Prediction of gestational hypertension by cosinor analysis of second trimester blood pressure.

Objective: We evaluated the efficacy of cosinor analysis of blood pressure (BP) at the second trimester in predicting the subsequent development of gestational hypertension.

Study design: We performed the cosinor analysis of BP in 313 normotensive non-proteinuric nulliparous women at the second trimester. We followed the pregnancy up to delivery and recorded the subsequent occurrence of gestational hypertension (sGH). We compared data from this group of 33 patients with those from the 280 women with uncomplicated normotensive pregnancy. We used the ANOVA to compare the means, statistical significance was assessed at p < .05.

Results: Diastolic MESOR of women with uncomplicated pregnancy was significantly lower than the GH patients, although both groups were definitely normotensive at the time of the recording. (Diastolic: Controls M = 62.2 +/- 1.5, A = 5.1 +/- 0.7, O = 14:07, p = .0001; sGH M = 73.5 +/- 6.2m, A = 5.9 +/- 1.1, O = 14:48, p = .003; Systolic: Controls M = 108.3 +/- 2.2, A = 5.2 +/- 0.7, O = 15:00, p = .0001; sGH M = 122.4 +/- 2.1, A = 4.1 +/- 0.8, O = 15:59, p = .01) We did not find any other significant difference among the population-mean cosinors. The most sensitive cutoff of diastolic blood pressure MESOR proved to be 68 mmHg.