Hypertensive disorders of pregnancy are a wide terminology encompassing conditions, including gestational hypertension, preeclampsia, and eclampsia. It is a prominent cause of maternal morbidity and mortality worldwide and affects around 10% of pregnancies. Pre-eclampsia and eclampsia together lead to 14% of maternal demise.
What does hypertension mean?
Hypertension in pregnancy is defined as systolic blood pressure more than or equal to 140 mm Hg and diastolic blood pressure greater than or equal to 90 mm Hg. The blood pressure recordings should always be taken multiple times on the same day and after proper rest to confirm the diagnosis. It is also advised to take recordings by mercury sphygmomanometer, and is preferred over automated and ambulatory blood pressure recording devices.
Classification of hypertension
Hypertensive disorders of pregnancy are classified into gestational hypertension, chronic hypertension, preeclampsia, and chronic hypertension superimposed by preeclampsia. It can also be classified based on severity. Non-severe hypertension is when systolic blood pressure is between 140-159 mm Hg and diastolic blood pressure is between 90-109 mm Hg, and severe hypertension is when systolic blood pressure is more than or equal to 160, and diastolic blood pressure is more than or equal to 110 mm Hg.
Chronic hypertension is high blood pressure that is present before conception or before 20 weeks of pregnancy. Gestational hypertension, on the other hand, is hypertension that appears for the first time after 20 weeks of gestation and resolves within three months post-delivery. Preeclampsia is gestational hypertension associated with at least one of the following: proteinuria, signs of maternal organ dysfunction, or uteroplacental dysfunction. Sometimes chronic hypertension can also be complicated by preeclampsia and is a separate entity.
Pathophysiology
The development of hypertension during pregnancy is due to the complex interplay between vasodilator and vasoconstrictor effects of various hormones and endogenous factors. In normal pregnancy, blood pressure initially decreases during the first half of gestation due to increased circulatory factors, which causes vasodilation. It returns to the pre-pregnant state by the end of the second trimester. Sometimes there can be reduced placental perfusion, leading to vascular endothelial dysfunction in the mother and a cascade of inflammatory reactions developing increased vascular resistance and hypertension.
What are the risk factors involved?
The risk factors for the development of preeclampsia include maternal age greater than 40 years, family history, obesity, diabetes mellitus, fetal hydrops, multiple gestation, renal disease, antiphospholipid syndrome, and vascular diseases.
What complications can hypertension cause during pregnancy?
Hypertension can cause short-term and long-term consequences. Short-term complications in the mother include seizure, stroke, hepatic damage, renal dysfunction, increased chances of caesarian section, preterm delivery, and placental abruption. In a fetus, hypertension can produce growth restriction, respiratory difficulties, and more admission to the intensive care unit. In the long run, the risk of recurrence of preeclampsia in subsequent pregnancies is increased, and also cardiovascular complications, renal diseases, and increased chances of cancer are observed.
An insight from mamahood
To conclude, a piece of advice to all mothers-to-be is to always seek expert help to manage hypertension during pregnancy. In the case of gestational hypertension, there are usually fewer complications. Nevertheless, close monitoring of blood pressure and abnormal symptoms is always needed to detect the development of preeclampsia, and antihypertensives should control blood pressure. In the case of preeclampsia, aggressive treatment with antihypertensives is mandatory. Baby should be delivered if gestational age is over 37 weeks and there is deterioration in the liver, kidney, brain, or blood. Preeclampsia is hence best managed at hospitals.
