Table 1.
Summary of the main studies on BP and circadian pattern during normal and abnormal pregnancies.
| Reference | n | Methods | Results | Comments |
|---|---|---|---|---|
| Seligman (1971) | n = 30 (10 normal BP, 10 HT, 10 PE) | Automatic recorder (24 h) Inpatients | Greater fall at night in HT Reduced fall at night in PE | Characteristics of the subject included are lacking (age, parity, weeks gestation) |
| Results and figures not detailed for every subject | ||||
| Redman et al. (1976) | n = 19 [3 severe PE, 4 mild HT, 12 primigravida w/mild HT (6 on methyldopa, 6 no treatment)] | Automatic recorder (48 h) Inpatients, bedrest At 24 and 36 w.g. | Reversed rhythm in severe PE Normal pattern in mild HT | Characteristics of the women included are lacking (age, parity) Results and figures not detailed for every subject |
| Sawyer et al. (1981) | n = 45 (15 normal BP, 15 chronic HT, 15 mild PE), third trimester | DINAMAP (24 h) Inpatients | Blunted fall at night in PE No diurnal variation in two severe PE (excluded from analysis) | Characteristics of the women included are lacking (age, parity not precised except for PE) |
| Beilin et al. (1983) | n = 31 [10 normal BP, 13 HT (antenatal BP normal), 8 PE] | DINAMAP (24 h) Inpatients | Same circadian rhythm in normo and hypertensive groups | Two HT and three PE under treatment when studied |
| >26 w.g. | No fall in BP in all PE, with four nocturnal HT | PE older, multiparous | ||
| Cugini et al. (1992) | n = 60 (30 non-pregnant, 30 pregnant women) | ABPM (24 h) At 8–10, 18–20, and 32–34w.g. | Reduced means BP for gestational HT. Values tend to increase in the second and third trimester | |
| Benedetto et al. (1996) | n = 212 (73 controls, 48 GH, 38 PE, 53 mild to moderate HT) | DINAMAP (24 h) Inpatients | BP oscillations less pronounced in GH and PE | Circadian parameters obtained by single cosinor method |
| Singleton pregnancy | At 8–16, 20–25, 28–35, 36–40 w.g. | Severity of HT favor the loss of diurnal rhythm, especially in PE | ||
| Halligan et al. (1996) | n = 48 (24 normal BP, 24 PE), 35 w.g. | ABPM (24 h) | Blunted BP nocturnal fallin PE. Inversely related to increase in BP mean | Preliminary, cross-sectional study Comparison of means and gradients |
| Tranquilli et al. (1996) | n = 114 (Normal BP, 36 IUGR, birthweight < fifth percentile, 78 normal IUG and birthweight | ABPM (24 h) At 24–28 w.g. | BP significantly elevated in IUGR although still in normal range | |
| Ayala et al. (1997) | n = 113 (71 uncomplicated pregnancy, 28 GH, 14 PE) | ABPM (48 h) Every 4 weeks after first obstetric visit | Significant difference in BP between healthy and complicated pregnancies present in the first 14 w.g. | |
| Olofsson and Poulsen (1997) | n = 56 GH (of which 34 PE) | ABPM (24 h) Inpatients (range 23–40 weeks gestation) | 12 SBP reversed rhythm, of which 10 PE. Associated with a more severe PE, smaller BP variation, maintenance of fetal growth, higher birthweight | No control group |
| Stoynev et al. (1999) | n = 31 pregnant women at low risk for HT | Automatic recorder (48 h) Inpatients | HR mesor increased in middle and late pregnancy. BP mesor unchanged | |
| Hermida et al. (2000) | n = 202 (124 normal pregnancy, 55 GH, 23 PE) | ABPM (48 h) Every 4 weeks after first obstetric visit until delivery | Difference in circadian variability present in the first 14 w.g. | Circadian parameters established by population multiple component-analysis |
| Brown et al. (2001) | n = 158 (63 PE, 68 GH, 27 HT) | ABPM (24 h) Inpatients or outpatients | High prevalence of nocturnal HT in PE and GH/essential HT | |
| Hermida et al. (2003) | n = 403 (235 uncomplicated pregnancies, 128 GH, 40 PE) | ABPM (48 h) Every 4 weeks after first obstetric visit until delivery | Difference in the circadian variability already in first trimester | Circadian parameters established by population multiple component-analysis |
| Hermida et al. (2004) | n = 434 (245 uncomplicated pregnancies 140 GH, 49 PE) | ABPM (48 h) Every 4 weeks after first obstetric visit until delivery | Significant difference in the 14 first w.g. between normal and complicated pregnancies | Circadian parameters established by population multiple component-analysis |
| Comparison of the 24 h mean of pulse pressure |
BP, blood pressure; SBP, systolic blood pressure; DBP, diastolic blood pressure; ABPM, ambulatory blood pressure monitoring; HT, hypertension; GH, gestational hypertension; IUGR, intrauterine growth retardation; w.g, weeks gestation; DINAMAP, device for indirect non-invasive automatic mean arterial pressure.