Pregnancy-induced hypertension (PIH) is defined as hypertension developing in a previously normal pregnant woman without other features of preeclampsia such as proteinuria. The condition is also named gestational hypertension, which has replaced the previously mentioned name.
The most common symptoms associated with pregnancy-induced hypertension include high blood pressure, edema or swelling, blurred vision or other visual changes, sudden unexplained weight gain, nausea, vomiting, pain in the upper right abdominal area, decreased urine output, and changes in kidney or liver function tests. Some women suffering from pregnancy-induced hypertension may be asymptomatic.
Routine measurement of blood pressure is advised during pregnancy. If high blood pressure was noticed for the first time in a pregnant woman, further workup is required to rule out other causes of hypertension such as coarctation of the aorta, systemic lupus erythematosus, Cushing syndrome, pheochromocytoma, or renal artery stenosis.
A systolic blood pressure above 140 mm Hg or diastolic more than 90 mm Hg during pregnancy and after the first 20 weeks of gestation is diagnostic for pregnancy-induced hypertension. However, high blood pressure should be confirmed by measurements in two different occasions and while the woman is seated.
Signs of preeclampsia and eclampsia, such as protein in the urine or seizures, are not present in patients with pregnancy-induced hypertension. However, urine should be tested to rule out preeclampsia.
A screening method has been developed by researchers from the United Kingdom to identify women at risk of pregnancy-induced hypertension or preeclampsia during the first trimester. The algorithm includes several factors such as uterine artery pulsatility index, pregnancy-associated plasma, mean arterial pressure, and placental growth factor .
There is a high risk of developing thrombophilias in women who are diagnosed with severe or early preeclampsia in the second or early trimester. The risk of recurrent preeclampsia may be decreased by the administration of anticoagulants in subsequent pregnancies; however, studies are still evaluating this.
Management of pregnancy-induced hypertension can be divided into different categories depending on the severity of the condition. It is controversial whether treatment is required for mild to moderate cases of pregnancy-induced hypertension. The risk associated with the treatment itself should be considered as it might outweigh the risks of the condition. However, treatment is recommended in cases linked to renal insufficiency.
Patients with mild or moderate hypertension, that is systolic blood pressure from 140 to 159 mm Hg or diastolic from 90 to 109 mm Hg, may benefit from changes in life habits such as decreased physical activity. However, drug therapy may be needed. Several medications can be used including beta blockers, calcium channel blockers, and methyldopa; however, ACE inhibitors and ARBs should be avoided in pregnant women. In cases of severe hypertension, such as systolic blood pressure equal to or more than 160 mm Hg or diastolic equal to or more than 110 mm Hg, the risk of developing maternal or fetal complications is highly elevated, which indicates the use of drug treatment. If systolic blood pressure is more than 180 mm Hg or the diastolic is more than 110 mm Hg, hospitalization may be required and treatment with multiple drugs may be indicated.
Pregnancy termination may be suggested if the condition worsens. Blood pressure should be measured routinely.
Pregnancy-induced hypertension can have many complications on both the mother and the fetus. Due to hypertension, the visual system is affected in many women . Other more severe complications include intracerebral hemorrhage, pulmonary edema, acute renal failure, eclamptic seizures, liver dysfunction, and coagulopathy. HELLP syndrome may also occur in women affected with pregnancy-induced hypertension, which includes elevated liver enzymes, thrombocytopenia, and microangiopathic hemolysis. The fetus may also be affected by the condition in different ways such as intrauterine growth restriction, premature delivery, abruptio placentae, and intrauterine fetal death. The resistance of blood vessels increases with high blood pressure, which hinders the blood flow in many organs in the mother such as the kidneys, brain, placenta, uterus, and liver. A severe condition known as eclampsia and characterized by dangerous seizures may develop in cases of untreated severe gestational hypertension. Many women with pregnancy-induced hypertension develop preeclampsia, which is a severe condition that requires adequate management  .
The exact etiology for gestational hypertension is unknown. However, there are several risk factors that increase the probability of developing it including diabetes mellitus, kidney disease, previous gestational hypertension, multiple fetuses pregnancy, pre-existing hypertension, and African-American decent.
Several risk factors and complications are associated with pregnancy-induced hypertension (PIH) . It is estimated that approximately 10% of pregnancies are complicated with PIH and they usually resolve within six weeks post partum . There is a 15% to 26% risk of developing superimposed preeclampsia ; however, this risk may vary depending on the gestational age of diagnosis. Women diagnosed after 36 weeks of pregnancy display a lower risk for the disorder. Women of an African-American decent appear to have a higher risk of experiencing gestational hypertension.
The main pathophysiology for the development of pregnancy-induced hypertension is unknown; however, it appears to be related to dysfunction of the vascular endothelium and its consequences such as capillary leak and generalized vasospasm. Generally, a correlation between the severity of systemic hypertension and the retinal vascular changes can be noted. The vasospastic features and manifestations are reversible and the retinal vessels return to normal quickly after delivery . Usually, the fetal and maternal outcomes are normal, especially in the absence of features of preeclampsia.
Pregnancy-induced hypertension may cause complications and may lead to maternal death in some cases. Even though it is not easy to prevent the development of the condition, women can decrease the risk by maintaining a balanced diet of fruits, vegetables, lean meat, and low-fat dairy products. Prenatal vitamins are recommended, especially calcium and folic acid. They help reduce the risk of developing pregnancy-induced hypertension. It is important to follow up patients through the whole pregnancy to prevent the developing of more serious conditions such as preeclampsia.
Hypertension diagnosed within the first 20 weeks of pregnancy is usually classified as chronic hypertension. However, if blood pressure elevation is discovered during pregnancy and after 20 weeks of gestation for the first time, it is considered gestational hypertension or pregnancy-induced hypertension  . It is characterized by systolic blood pressure equals to or more than 140 mm Hg or diastolic equals to or more than 90 mm Hg. Severe gestational hypertension is defined as systolic blood pressure more than 160 mm Hg or diastolic more than 110 mm Hg . Women with gestational hypertension in a previous pregnancy, diabetes mellitus, or renal disease have higher risks of developing pregnancy-induced hypertension. It is also found more often among women from African-American decent.
Patients will present with symptoms related to hypertension, such as elevated blood pressure, edema, abdominal pain, nausea, vomiting, and unexplained weight gain. The diagnosis of gestational hypertension should be confirmed by measuring blood pressure in two different occasions while the woman is seated. Urine should also be tested for proteins in order to check for preeclampsia.
Management will depend on the severity of the condition. Patients with severe hypertension will usually require a combination of drug therapy including calcium channel blockers, beta blockers, and methyldopa (ACE inhibitors and ARBs should be avoided during pregnancy). Women with mild hypertension and no renal involvement may not require any drug therapy. However, if renal insufficiency is present, it is advised to medication is advised. Several maternal and fetal complications may develop in patients suffering from gestational hypertension such as visual disturbance, renal disease, liver disease, preeclampsia, intrauterine growth restriction, or fetal death. It is important to decrease the risk of developing complications by maintaining a well-balanced diet with low fat as well as taking vitamins and supplements such as calcium and folic acid.
Pregnancy-induced hypertension, also called gestational hypertension, is defined as elevated blood pressure diagnosed for the first time in a pregnant woman after 20 weeks of gestation, which usually resolves after delivery. It is characterized by systolic blood pressure more than 140 mm Hg or diastolic more than 90 mm Hg.
The main cause of pregnancy-induced hypertension is not well understood. However, there are several factors that may increase the risk of developing the condition in certain women. These include diabetes mellitus, kidney disease, and gestational hypertension in a previous pregnancy. The risk of developing gestational hypertension appears to be higher among women of African-American decent.
Some women suffering from pregnancy-induced hypertension may not have any symptoms at all. However, if features do develop, they include elevated blood pressure, swelling, nausea, vomiting, weight gain, visual disturbance, changes in urine output, and abdominal pain.
Blood pressure should be measured in two different occasions in order to confirm the diagnosis. A systolic blood pressure above 140 mm Hg or diastolic blood pressure above 90 mm Hg during the gestational period is diagnostic of the condition. Urine will be tested for the presence of proteins in order to rule out another condition called preeclampsia.
Treatment of pregnancy-induced hypertension differs from patient to patient, depending on the severity of the condition. Women with mild elevation in blood pressure and no renal involvement may not require drug therapy. Habit changes, such as decreased physical activity, may suffice. However, in cases with renal insufficiency or severe elevation of blood pressure drug treatment may be needed. Different medications may be used during pregnancy, and in some cases a combination may be prescribed to control blood pressure.
The outcomes of pregnancy-induced hypertension depend on the severity of the condition. Women with severe elevations in blood pressure show a higher risk of developing maternal or fetal complications. Fetal complications include premature delivery, intrauterine fetal death, growth restriction, and abruption of the placenta. Maternal complications comprise visual disturbance, intracerebral hemorrhage, renal failure, liver dysfunction, pulmonary edema, and a syndrome called HELLP. A severe condition called preeclampsia may develop in women suffering from pregnancy-induced hypertension.
It is not easy to prevent the developing of the condition. However, it is important to avoid risk factors. Eating a balanced diet with fruits and vegetables and decreasing fat intake will decrease the risk of developing the condition and its complications. Intake of vitamins, such as folic acid and calcium, is highly recommended during pregnancy.