Hypertension is the most frequent complication of pregnancy. NICE guidance advises how to care for women who have, or are at risk of developing, the condition
The management of hypertensive disorders of pregnancy varies greatly in both primary and secondary health care settings. The recently published guideline from the National Institute for Health and Clinical Excellence provides guidance for midwives, general practitioners and obstetricians on how best to provide care for women with, or at risk of developing, hypertension during their pregnancy. It also provides guidance on postnatal care and treatment for those women who do develop the condition.
Hypertension is the most frequent complication of pregnancy, occurring in about 10 per cent of pregnancies, and pre-eclampsia is one of the main causes of maternal and fetal morbidity and mortality (CEMACH, 2004, 2007). Pre-eclampsia is also associated with fetal growth restriction, low birth weight, pre-term birth and respiratory distress syndrome (The Magpie Collaborative Group, 2002). National guidance already exists for the care and treatment of women with severe pre-eclampsia, eclampsia as well as screening for hypertension, but there is little guidance on the assessment and care after the diagnosis of new onset hypertension, or for women with chronic hypertension. This evidence-based guideline, with clear recommendations will therefore be invaluable to all healthcare professionals providing care to women planning a pregnancy, during pregnancy, and following birth.
Symptoms of pre-eclampsia include: severe headache, visual problems such as blurred vision or flashing before the eyes, severe pain just below the ribs, vomiting, and sudden swelling of the face, hands or feet.
The guideline gives definitions of the various types of hypertension including chronic hypertension, gestational hypertension, mild, moderate and severe hypertension, as well as mild, moderate and severe pre-eclampsia. It also provides parameters of blood pressure recordings within these definitions, as well as management options for clinicians in both primary and secondary health care settings.
Risk factors that increase the risk of developing hypertension during pregnancy are categorised into moderate and high risk factors. Moderate risk factors include:
First pregnancy, older mothers-to-be (aged over 40 years) body mass index (BMI) over 35 at first antenatal visit, pregnancy interval more than 10 years, family history of pre-eclampsia, and multiple pregnancy.
- Advise women who have had pre-eclampsia to keep or achieve a healthy BMI before their next pregnancy;
- Inform women with hypertension who are planning a pregnancy, that angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs), used to control hypertension in non-pregnant women, can increase the risk of congenital abnormalities if taken during pregnancy. Discuss a more suitable form of antihypertensive treatment with women as soon as their pregnancy is confirmed;
- Offer women with hypertension or pre-eclampsia, a care package that includes admission to hospital, antihypertension treatment, measurement of blood pressure, blood tests and tests for proteinuria;
- Women with uncomplicated chronic hypertension should aim to keep their blood pressure lower than 150/100 mmHg and their diastolic blood pressure should not fall below 80mmHg. Antihypertension treatment in these women will depend upon pre-existing treatment, side effect profiles and teratogenicity (risk of congenital malformation)Additional antenatal consultations will be based on the individual needs of the woman and her baby.
Interestingly, this evidence-based guidance does not advocate the use of nutritional supplements such as magnesium, fish oils, garlic or anti-oxidents such as vitamins C and E to prevent the development of hypertensive disorders of pregnancy. However, it does provide advice on follow up care in the primary care setting, particularly with regard to the monitoring of blood pressure, antihypertensive therapy treatments and breast feeding, as well as the longer term sequelae of hypertension in pregnancy.
A number of research recommendations have been made including:
- How clinically and cost effective is calcium supplementation (compared with placebo) for the prevention of pre-eclampsia in women at both moderate and high risk of pre-eclampsia?
- How should significant proteinuria be defined in women with hypertension in pregnancy?
- When should women with mild pre-eclampsia with mild or moderate hypertension give birth?
It is hoped this guideline will enable clinicians to provide the best possible care to women at risk of developing, or who do develop hypertension in pregnancy.
Authors Lynda Mulhair MSc, RN, RM, ADM, PGCEA, PGCCU, is a consultant midwife, antenatal day assessment unit, Guy’s and St. Thomas’ NHS Foundation Trust, London. Rachel Fielding MSc, RN, RM, ADM, SoM, is deputy director of midwifery, North Bristol NHS Trust. Both are members of the NICE guideline development group
The guideline is available for download at www.nice.org.uk/CG107
Altman D et al (2002). Do women with pre-eclampsia, and their babies, benefit from mangesium sulphate?The Magpie Trial: a randomised placebo-controlled trial. The Lancet; 359:1877-1890.
Confidential Enquiries into Maternal and Child Health (2007) Saving Mothers Lives. 7th Report of Confidential Enquiries into Maternal and Child Health 2003–2005. London: Royal College of Obstetricians and Gynaecologists.
Confidential Enquiries into Maternal and Child Health (2004) Why Mothers Die.6th Report of CEMACH 2000–2002. London: Royal College of Obstetricians and Gynaecologists.