Background: Primary aldosteronism (PA) is a prevalent but underdiagnosed cause of endocrine hypertension associated with increased cardiovascular risk independent of blood pressure (BP). Its contribution to hypertensive disorders of pregnancy and obstetric complications remain poorly understood.
Aims: To compare BP trajectories across pregnancy and postpartum, and pregnancy outcomes between women with PA-associated hypertension and women with other hypertension diagnoses.
Methods: This case-control study included women attending the Monash Health Endocrine Hypertension Clinic who had delivered a singleton pregnancy. Cases had confirmed PA while controls had non-PA hypertension. BP measurements across pregnancy and postpartum were analysed. Pregnancy outcomes included hypertensive disorders of pregnancy, fetal and neonatal complications, and postpartum hypertension.
Results: Ninety-six women with 181 pregnancies were included (51 PA; 45 non-PA). Women with PA had lower rates of hypertensive disorders of pregnancy, including preeclampsia, compared with non-PA hypertension (35% vs 64%, p=0.004). They also had lower BP throughout pregnancy (SBP β −7.4 mmHg, 95%CI −12.1 to −2.6; DBP β −5.2 mmHg, 95%CI −8.2 to −2.3), which persisted after adjustment for gestational age, but was attenuated after adjustment for antihypertensive therapy. Other maternal and neonatal complications, including gestational diabetes, fetal growth restriction, preterm birth, low birth weight and NICU admission, were comparable between groups. From pregnancy to postpartum, women with PA demonstrated smaller BP reductions compared with non-PA hypertension (SBP change −0.5 vs −11.8 mmHg, p=0.02), with similar findings for diastolic BP.
Conclusions: Women with PA experienced high rates of pregnancy complications which were comparable to women with non-PA hypertension, although whether PA was present at the time of pregnancy is uncertain. Lower BP and fewer hypertensive disorders during pregnancy, but less postpartum BP improvement, may reflect attenuation of aldosterone-mediated hypertension during pregnancy by progesterone. Prospective studies are needed to define PA prevalence, diagnostic strategies and optimal management during pregnancy.