PLASMA-LEVELS OF ATRIAL-NATRIURETIC-PEPTIDE IN NORMAL AND HYPERTENSIVE PREGNANCIES - A METAANALYSIS

OBJECTIVE: Our goals were (1) to use meta-analysis to determine whethe r pregnancy and the puerperium are accompanied by alterations in plasm a atrial natriuretic peptide levels when compared with the nonpregnant state and (2) to evaluate the additional effects of hypertensive dise ase during pregnancy on plasma atrial natriuretic peptide levels. STUD Y DESIGN: Articles measuring atrial natriuretic peptide levels during pregnancy were reviewed. Data from articles meeting inclusion criteria were abstracted, and a meta-analysis was performed with the use of th e maximum likelihood methods of Jennrich and Schluchter (Biometrics 19 86;42:805-20). RESULTS: The mean atrial natriuretic peptide level in n onpregnant control subjects was 28.7 pg/ml (95% confidence interval 22 .5 to 36.7). The mean plasma atrial natriuretic peptide level rose 41% to 40.5 pg/ml (95% confidence interval 31.7 to 51.8) in the third tri mester (p < 0.0001). It was 71.1 pg/ml (95% confidence interval 51.2 t o 98.7) or 148% greater than the mean nonpregnant level during the fir st week post partum (p < 0.0001). Compared with levels in pregnant con trol subjects, plasma atrial natriuretic peptide levels increased 52% to 52.1 pg/ml (95% confidence interval 32.9 to 82.5) in women with ges tational hypertension (p < 0.005) and 130% to 78.8 pg/ml (95% confiden ce interval 52.3 to 118.8) in women with preeclampsia (p < 0.0001). Ch ronic hypertension did not significantly alter atrial natriuretic pept ide levels. CONCLUSIONS: The 41% increase in atrial natriuretic peptid e levels in the third trimester suggests that atrial stretch receptors sense the expanded blood volume as normal to moderately increased. Th e rise in atrial natriuretic peptide during the first week post partum is consistent with known hemodynamic changes and suggests that atrial natriuretic peptide may be involved in the postpartum diuresis. The m arked increase in plasma atrial natriuretic peptide levels observed in preeclampsia is not likely to result from elevated arterial pressures alone but may reflect underlying factors unique to this disease proce ss.