Maternal BP and the Risk of Hypertensive Disorders of Pregnancy at High Altitudes

Takeaway

• Systemic arterial blood pressure (BP) was higher at full term in pregnancies at high altitudes (>2500 m) compared with low altitudes (<2500 m), which was associated with an increased risk of gestational hypertension, but not pre-eclampsia.
• In addition, the risk of stillbirth was greater at high altitudes.

Why this matters

• Findings emphasise the importance of BP monitoring during pregnancy at high altitudes, as this population may be at a higher risk of complications resulting from high BP.

Study design

• Researchers at the University of Cambridge performed a meta-analysis of 27 studies involving 1,721,984 pregnancies, identified through a search across electronic databases.
• Funding: None.

Key results

• Maternal systolic BP (SBP; 4.8±1.6 mmHg; P<.01) and diastolic BP (DBP; 4.0±0.8 mmHg; P<.001) at term were higher at high vs low altitudes.
• The magnitude of difference was similar for both SBP and DBP.
• Hypertensive disorders of pregnancy were significantly more common in pregnancies at high vs low altitudes (OR, 1.31; 95% CI, 1.03-1.65; P<.05; I², 52.5%).
• The risk of gestational hypertension was almost twice as likely in high altitude pregnancies than in low altitude pregnancies (OR, 1.92; 95% CI, 1.15-3.22; P<.05; I², 66.8%).
• The risk of pre-eclampsia was significantly lower in high vs low altitude pregnancies (OR, 0.57; 95% CI, 0.46-0.70; P<.001; I², 95.2%).
• The risk of stillbirth was higher in high altitude pregnancies vs low altitude pregnancies (OR, 1.63; 95% CI, 1.12-2.35; P<.01; I², 85.0%).

Limitations

• Heterogeneity among studies.

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.