Vol. 17,N° 22 - 18 Sep 2019
Dr. Ghada Sayed Youssef
Hypertension (HTN) is the most commonly encountered disorder during pregnancy. High blood pressure has a negative impact on the mother and the foetus, which is why early diagnosis and proper control are mandatory to avoid complications. There are many forms of HTN disorder during pregnancy. The threshold for initiation of antihypertensive medications differs for gestational and chronic HTN during pregnancy, being lower in gestational HTN. Pre-eclampsia/eclampsia syndrome is a severe form of gestational HTN, which is only curable by delivery of the foetus. Management of HTN during pregnancy is challenging and it requires collaboration between obstetricians and cardiologists.
Introduction and prevalence
Hypertension (HTN) is a worldwide health problem that affects about 25-40% of individuals. It is a major cardiovascular risk factor and it is associated with many cardiovascular complications (e.g., stroke, heart failure). The prevalence of raised blood pressure is highest in Africa, where it is 46% for both sexes combined. HTN can affect people at any age; women at child-bearing age are no exception.
HTN is the most common medical disorder during pregnancy, with a prevalence of 5-10% of all pregnancies worldwide [1,2]. HTN and antihypertensive drugs have adverse effects on both the mother and the foetus.
Management of HTN during pregnancy needs expertise in the field of high-risk pregnancy and cardiovascular diseases, which is why a combined team of obstetricians and cardiologists is an important prerequisite.
Definition and forms of HTN disorders in pregnancy
Diagnosis of HTN during pregnancy is based on the standard office blood pressure (BP) measurements. Although ambulatory blood pressure monitoring (ABPM) is more accurate in diagnosing HTN and is better in predicting outcomes , it cannot be routinely applied because of time and money constraints. The use of automated BP measuring devices is not recommended because they tend to under-record BP and they are unreliable in pre-eclampsia .
Hypertension disorders in pregnancy (HDP) are classified into mild HTN (systolic BP 140-159 mmHg and/or diastolic BP 90-109 mmHg) or severe HTN (BP ≥160/110 mmHg) .
The nomenclature of the different forms of HDP depends on the timing of the first diagnosis of HTN and the persistence of high BP after delivery. The following forms are described in the recent European guidelines :
- Pre-existing hypertension
HTN diagnosis before pregnancy, early in pregnancy (before 20 weeks of gestation),or HTN continues after six weeks post-partum.
- Gestational hypertension
HTN first diagnosis during pregnancy, after 20 weeks of gestation; it usually resolves within six weeks post-partum. Gestational HTN is considered a form of secondary HTN .
- Pre-existing hypertension plus superimposed gestational hypertension with proteinuria
- Pre-eclampsia (vide infra)
- Antenatally unclassifiable hypertension
This term is used when HTN is first diagnosed after 20 weeks of gestation and it is unclear if hypertension was pre-existing. Reassessment six weeks post-partum will help distinguish pre-existing from gestational hypertension.
In addition to the well-known risks of HTN, maternal risks include placental abruption and disseminated intravascular coagulation.
The foetus is at high risk of intrauterine growth retardation (25% of cases of pre-eclampsia), prematurity (27% of cases of pre-eclampsia), and intrauterine death (4% of cases of pre-eclampsia) .
The long-term risks of HDP and pre-eclampsia include a fourfold higher risk of chronic HTN and a twofold higher risk of stroke and ischaemic heart diseases .
Women who develop severe hypertension have higher rates of adverse maternal (pre-eclampsia, HELLP syndrome [haemolysis, elevated liver enzymes, and a low platelet count], and maternal length of hospital stay ≥10 days) and perinatal outcomes (perinatal death, high-level neonatal care for >48 hrs, birth weight <10th percentile, pre-eclampsia, and pre-term delivery) .
Basic laboratory workup includes haemoglobin and haematocrit, urinalysis, liver enzymes, serum creatinine, and serum uric acid . Hyperuricaemia in HDP is considered a marker of adverse maternal and foetal outcomes . Proteinuria defines renal affection. A dipstick test of >1+ warrants further investigations such as an albumin-creatinine ratio (ACR), that can be measured by a single spot urine sample. An ACR cut-off level of 30 mg/mmol can be used to identify proteinuria. Specific tests should be carried out whenever secondary HTN is suspected.
Doppler ultrasound of the uterine arteries (performed after 20 weeks of gestation) can detect those at a higher risk of gestational hypertension, pre-eclampsia, and intrauterine growth retardation .
Gestational hypertension with significant proteinuria (>0.3 g/24 hrs or ≥30 mg/mmol ACR). As proteinuria may be a late manifestation of pre-eclampsia, it should be suspected when de novo HTN is associated with symptoms (e.g., headache, visual disturbances, abdominal pain, or abnormal laboratory tests). Eclampsia is a severe form of pre-eclampsia associated with generalised tonic-clonic seizures . In a few cases, pre-eclampsia may develop in the early post-partum period.
Women at increased risk of developing pre-eclampsia are primigravida, those with multiple pregnancy, morbid obesity (body mass index [BMI] >35 kg/m2), diabetes mellitus, renal disease or autoimmune diseases (i.e., systemic lupus erythematosus, antiphospholipid syndrome). Chronic pre-existing hypertension, a history of pre-eclampsia in a previous pregnancy or familial history of pre-eclampsia are also considered risk factors for developing pre-eclampsia .
This is still unclear, but many theories propose a placental vascular insufficiency due to endothelial dysfunction, vasoconstriction and micro-thrombosis. Oxidative stress of the syncytiotrophoblast (the epithelial covering of the placental villi in contact with maternal blood) is one of the explanations. When stressed, the syncytiotrophoblast releases many factors, including pro-inflammatory cytokines, anti-angiogenic agents, exosomes and cell-free foetal DNA, into the maternal circulation. These disrupt maternal endothelial function resulting in a systemic inflammatory response and cause hypertension and other manifestations of the disease (haematologic, cardiac, neurologic, pulmonary, renal, and hepatic dysfunction) . Genetics may also play a role.
Maternal complications include multiple organ failure. Maternal mortality is estimated to be 9% in the United States of America (USA), which is why the USA preventive task force recommended measuring the BP at every prenatal visit . Foetal growth restriction occurs due to placental insufficiency and is a common cause of premature delivery .
Pre-eclampsia accompanied by haemolysis, elevated liver enzymes and low platelets is called HELLP syndrome. HELLP is a life-threatening condition which may be fatal if not detected and treated early. The global mortality rate of HELLP syndrome has been reported to be as high as 25% .
Currently, there is no sure way to prevent hypertension and there is no clear role for lifestyle modifications in reducing HDP .
The aim of prescribing antihypertensive medications is to decrease progression to severe HTN and to prolong pregnancy till foetal maturity .
Hospitalisation is needed for patients with severe HTN.
The threshold for initiation of antihypertensive medications is ≥150/95 mmHg for patients with pre-existing HTN and >140/90 mmHg for patients with gestational HTN (with or without proteinuria) and patients with subclinical hypertension-mediated organ damage (HMOD) . The target BP should be <140/90 for all hypertensive pregnant women. Because of the physiological drop of BP in the second trimester, some women become able to withdraw their antihypertensive medication .
Both maternal hypertension and maternal antihypertensive use during pregnancy were associated with increased risk of congenital heart diseases (CHDs) such as pulmonary valve stenosis, secundum atrial septal defect, ventricular septal defect and coarctation of the aorta. Hypertensive mothers who reported antihypertensive use had higher risk of these CHDs than untreated mothers . That is why the pregnancy and lactation labelling rule (PLLR) system must be checked before prescribing any drugs to pregnant women.
Drugs for mild HTN
Beta-blockers (BB) are first-line medication during pregnancy and lactation. Labetalol is one of the commonest drugs used in HDP. It can be used parenterally in cases of severe HTN. BB may cause foetal bradycardia or intrauterine growth retardation; thus, proper monitoring of the foetus is essential. Atenolol is better avoided during pregnancy .
This is an ᾳ2-adrenergic agonist that has central nervous system (CNS) and peripheral nervous system effects. It is one of the safest drugs during pregnancy; been used for more than 40 years, with no serious side effects on the mother or the foetus, although it has been largely displaced by labetalol as the first-line agent of choice for most patients. The recommended daily dose of methyldopa is 0.5–3.0 g in 2–4 doses.Side-effects include sleepiness, dry mouth, general malaise, haemolytic anaemia, and hepatopathy .
Calcium channel blockers
Calcium channel blockers (CCBs) are among the recommended antihypertensive drugs during pregnancy. Both dihydropyridines and non-dihydropyridines are allowed .
The use of diuretics during pregnancy carries a potential risk of oligohydramnios. Unless there is a compelling indication for the use of diuretics (e.g., heart failure), their use is not recommended. Diuretic therapy is better avoided in pre-eclampsia because the plasma volume is contracted . Only loop diuretics are allowed, while thiazide and potassium-sparing diuretics are contraindicated during pregnancy.
Renin-angiotensin-aldosterone system inhibitors
Renin-angiotensin-aldosterone system (RAAS) inhibitors include angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), renin inhibitors, non-selective (spironolactone) and selective (eplerenone) aldosterone antagonists.
Recent studies suggest that exposure early in pregnancy during the period of organogenesis does not confer an increase in the risk of malformations . However, animal and human data suggest that RAAS inhibitor use during the second and third trimesters is associated with a higher risk of complications, including renal dysplasia, pulmonary hypoplasia, and growth restriction .
The guidelines recommend against the use of RAAS inhibitor drugs during pregnancy and lactation (Class III recommendations). Beta-blockers are used as an alternative to ACEIs and ARBs in younger hypertensive women planning pregnancy .
Drugs for severe HTN
HDP emergency is defined as BP ≥170/110 mmHg. It necessitates immediate hospital admission and parenteral antihypertensive medications . Intravenous labetalol and nicardipine as well as oral methyldopa and CCB can be used. Hydralazine is now only used when other drugs fail to control HTN, because of its increased perinatal adverse effects .
Treatment of pre-eclampsia/eclampsia syndrome
- Women at a risk of developing pre-eclampsia should be advised to take 100–150 mg of aspirin daily from weeks 12–36 gestation . Aspirin can decrease the risk of pre-eclampsia by 12% and the risk of premature delivery by 14% .
- Women with a diagnosis of pre-eclampsia should be admitted and offered antihypertensive medications, if not previously given. Intravenous labetalol and nicardipine are usually used to lower the BP but foetal bradycardia is a concern. In case of pulmonary oedema, nitroglycerine infusion is recommended. The consensus is to reduce BP to levels lower than 160/105 mmHg.
- Intravenous magnesium sulfate is the treatment of choice in patients with eclampsia fits.
- Delivery of the placenta (and the foetus, of course!) is the only cure for pre-eclampsia; yet, in asymptomatic patients, delivery can be delayed to the 37th week of gestation.
Timing and mode of delivery
Vaginal delivery is preferred unless there are obstetric or medical contraindications.
Delivery at 37 weeks is recommended in uncomplicated patients. Women with pre-eclampsia with visual or haemostatic disorders or HELLP syndrome should be delivered as soon as possible .
Management of HTN post-partum
When HTN persists after delivery, antihypertensive drugs should be continued. Almost all drugs are secreted in milk, but in varying amounts . Because of the lack of evidence, most physicians use the same rules applied for drugs during pregnancy in the breastfeeding period. Methyldopa should be avoided because of the risk of post-partum depression.
HDP is a heterogenous disease that increases the risk of maternal and foetal morbidity and mortality. Early detection and management are warranted by routine measurement of BP at the regular antenatal care visits. Obstetricians and cardiologists should share in the management of HDP.
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Notes to editor
Ghada Sayed Youssef1,2, MD
- Assistant Professor of Cardiology, Kasr Al Ainy Hospitals, Cairo University, Cairo, Egypt;
- Moderator of High-Risk Pregnancy Unit, Cairo University, Cairo, Egypt
Address for correspondence:
Dr Ghada Sayed Youssef, Kasr Al Ainy Hospitals, Cardiology Department, Cairo University, Cairo, Egypt
Tel: (+20) 11 511 889 99
The author has no conflicts of interest to declare.
The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.
What causes hypertension in pregnancy? ›
The cause of gestational hypertension is unknown. Some conditions may increase the risk of developing the condition, including the following: Pre-existing hypertension (high blood pressure) Kidney disease.What happens if a pregnant woman has high blood pressure? ›
If blood pressure goes up during pregnancy, it can place extra stress on your heart and kidneys. This can lead to heart disease, kidney disease, and stroke. High blood pressure during pregnancy also increases the risk of preeclampsia, preterm birth, placental abruption, and cesarean birth.What is the treatment for hypertension during pregnancy? ›
|Drug (FDA Risk)*||Dose|
|Labetalol (C)||200 to 1200 mg/d in 2 to 3 divided doses|
|Nifedipine (C)||30 to 120 mg/d of a slow-release preparation|
|Hydralazine (C)||50 to 300 mg/d in 2 to 4 divided doses|
|β-Receptor blockers (C)||Depends on specific agent|
When you have preeclampsia, your blood pressure is elevated (higher than 140/90 mmHg), and you may have high levels of protein in your urine. Preeclampsia puts stress on your heart and other organs and can cause serious complications.How does hypertension affect a fetus? ›
High blood pressure during pregnancy can affect the development of the placenta, causing the nutrient and oxygen supply to the baby to be limited. This can lead to an early delivery, low birth weight, placental separation (abruption) and other complications for the baby.Does stress cause preeclampsia? ›
Stress may lead to high blood pressure during pregnancy. This puts you at risk of a serious high blood pressure condition called preeclampsia, premature birth and having a low-birthweight infant.What food lowers blood pressure quickly? ›
What can I eat to lower my blood pressure immediately? While there's no miracle food that can lower blood pressure immediately, consuming a diet rich in vegetables, fruit, whole grains, nuts, seeds, and fish (and low in red meat, salt, and added sugars) may help lower blood pressure over time.When is blood pressure an emergency pregnancy? ›
A sudden spike in blood pressure (more than 160/110 mm HG) can also happen during pregnancy or after the baby is born. This is a medical emergency.What is first line treatment for hypertension in pregnancy? ›
Background: Hydralazine, labetalol, and nifedipine are the recommended first-line treatments for severe hypertension in pregnancy.Is bed rest good for high blood pressure? ›
Bed rest can help control your blood pressure and may help keep your heart from beating too fast. If your heart rate slows down, less blood will be pumped into your arteries which helps keep your blood pressure stable. As long as your blood pressure remains mild, you can take care of it outside of the hospital.
What is stage 1 hypertension in pregnancy? ›
Elevated. This is when your systolic blood pressure is between 120-129 and your diastolic pressure is less than 80. Stage 1 high blood pressure. This is when your systolic pressure is between 130-139 or your diastolic pressure is between 80-89.What were your first signs of preeclampsia? ›
The first signs of preeclampsia are often detected during routine prenatal visits with a health care provider. Along with high blood pressure, preeclampsia signs and symptoms may include: Excess protein in urine (proteinuria) or other signs of kidney problems. Decreased levels of platelets in blood (thrombocytopenia)Does bed rest help preeclampsia? ›
False: trials have shown no strong evidence that bedrest benefits preeclampsia patients. Bedrest can have some difficult side effects too: it is known to raise your risk of depression, bone loss, and blood clots.Can a baby survive preeclampsia? ›
Most pregnant women with preeclampsia have healthy babies. But if not treated, it can cause serious problems, like premature birth and even death.Can hypertension cause birth defects? ›
Chronic Hypertension During Pregnancy May Lead to Congenital Birth Defects. Women who develop hypertension and preeclampsia early in pregnancy may give birth to babies who have increased chances of congenital heart defects and genitourinary abnormalities, an SPH-led study found.What is the difference between pregnancy induced hypertension and preeclampsia? ›
Pregnancy-induced hypertension is a rise in blood pressure, without proteinuria, during the second half of pregnancy. Pre-eclampsia is a multisystem disorder, unique to pregnancy, that is usually associated with raised blood pressure and proteinuria. It rarely presents before 20 weeks' gestation.What are signs of hypertension in pregnancy? ›
Signs and symptoms include nausea and vomiting, headache, upper right belly pain, and a general feeling of illness or being unwell. Sometimes, it develops suddenly, even before high blood pressure is detected. It also may develop without any symptoms.What is first-line for hypertension in pregnancy? ›
Background: Hydralazine, labetalol, and nifedipine are the recommended first-line treatments for severe hypertension in pregnancy.Which drug is used for hypertension in pregnancy? ›
For emergency treatment in preeclampsia, IV hydralazine, labetalol and oral nifedipine can be used . The ACOG Practice Bulletins also recommend that methyldopa and labetalol are appropriate first-line agents and beta-blockers and angiotensin-converting enzyme inhibitors are not recommended [21, 17].Does bed rest help gestational hypertension? ›
Women with high blood pressure are often advised to rest in bed either at home or in hospital. It is suggested that this might help to reduce the mother's blood pressure and so provide benefits for the baby.
Who is at risk for gestational hypertension? ›
Having high blood pressure before pregnancy or with a past pregnancy. Having kidney disease. Having diabetes. Being younger than 20 years of age or older than 40 years of age.When should I go to the hospital for high blood pressure during pregnancy? ›
Seek urgent, immediate medical care at the hospital if:
Your blood pressure is very high, such as 160/110 or higher. You have symptoms of pre-eclampsia, such as: Sudden swelling of your face, hands, or feet. New vision problems (such as light sensitivity, blurring, or seeing spots).
Stress may lead to high blood pressure during pregnancy. This puts you at risk of a serious high blood pressure condition called preeclampsia, premature birth and having a low-birthweight infant. Stress also may affect how you respond to certain situations.How do you lower high blood pressure quickly? ›
- Take a warm bath or shower. Stay in your shower or bath for at least 15 minutes and enjoy the warm water. ...
- Do a breathing exercise. Take a deep breath from your core, hold your breath for about two seconds, then slowly exhale. ...
The first choice is usually a thiazide diuretic.