Hypertensive disorder in pregnancy
Hypertensive disorder affected about 6 to 8% of pregnancies and it is the leading cause of maternal and neonatal mortality in the United States. In Malaysia, the rate is quite high when it is reported that hypertensive disease in pregnancy has contributed almost 14% of maternal death.
Hypertension is a systolic blood pressure at 140mmHg and above or a diastolic blood pressure above > 90mmHg.The hypertension can be classified into several categories as follows:
|
Type |
Characteristics |
|
Gestational hypertension |
Mild: Systolic < 160 mmHg Diastolic < 110 mmHg Severe: Systolic >160 mmHg Diastolic > 110 mmHg
|
|
Gestational proteinuria |
Mild ( < 1 + on dipstick and <5 g/24h) Severe (>5 g/24h)
|
|
Preeclampsia (hypertension + proteinuria) |
Onset > 20weeks’ gestation Mild: Mild hypertension ad mild proteinuria Severe: Severe hypertension and proteinuria Mild hypertension and severe proteinuria Persistently severe cerebral symptoms Thrombocytopenia Pulmonary edema Oliguria (<500mL/24 h)
|
|
Chronic hypertension |
Hypertension before pregnancy Hypertension before 20 weeks’ gestation
|
|
Superimposed preeclampsia |
Exacerbation of hypertension and/or new-onset proteinuria |
Source: Coppage, K.H. and Sibai, B.M. Hypertension Emergencies. In Foley, M.R.., Strong T.H.J and Garite, T.J. editors. Obstetric Intensive Care Manual 2nd edition. Mc Graw-Hill Medical Publishing; 2004.p. 5 1-65
Gestational hypertension is defined by the elevation of blood pressure during the second half of pregnancy or beyond 6 weeks postpartum. It happens without the presence of symptoms and proteinuria. It can be divided into mild or severe gestational hypertension depending on the degree of the blood pressure.
Chronic hypertension occurred when the patient is diagnosed with hypertension at earlier stage (the onset before 20 weeks gestation) or even before the pregnancy itself. It is also considered chronic hypertension if the hypertension persists longer than six weeks post partum. In this case, thorough investigation and examination should be done to this patient to look for causes of hypertension. We need to rule out hyperlipidaemia, connective tissue disease or phaemochromocytoma (particularly in young patients). We can only conclude it as essential hypertension if all investigations come back negative. Essential hypertension is commoner in older multips and may present before the pregnancy. Those women with this disease are more likely to develop preeclampsia if we compare with those who are normotensive.
Ideally, hypertensive disorder in pregnancy should be managed by an obstetrician. However, primary care practice has its own approach and definitely playing a major role in preventing, detecting, monitoring and managing this disease and its complication till certain extent. This includes both during preconceptional and antenatal stage. During pre pregnancy stage, women with known chronic hypertension and currently on antihypertensive agents should be change to methyldopa and labetalol. Methyldopa is a centrally acting antihypertensive agent and is limited to be use during pregnancy in view of its side effects. Atenolol (a beta blocker) is not recommended because it has shown to lead to fetal growth restriction. Angiotensin converting enzymes inhibitor (ACEI) and angiotensin receptor blocker (ARB) is contraindicated for use in pregnancy in view of its potential to increase fetal and neonatal mortality hence should be avoided during preconceptional stage. For acute severe hypertension, parenteral hydralazine should not be the drug of choice in view of its potential of more maternal and perinatal adverse effects in comparison with other type of drugs particularly intravenous labetalol, oral or sublingual nifedipine. Nifedipine is a calcium channel blocker and is known to be very effective in lowering the blood pressure. Intravenous labetalol has fewer side effects on maternal hypotension, fewer placental abruptions and fewer low apgar score of the fetus. Sublingual nifedipine is phased out in view of it may cause sudden drop of blood pressure. Furthermore, it may lead to placenta hypoperfusion which later will compromise the fetus outcome.
Women who delivered low birth weight babies were 5 times more likely to have had pregnancy induced hypertension compared to mother who delivered normal weight babies. As addition, women with a history or experience in hypertension in pregnancy had significantly increased risk of hypertension, myocardial infarction and ischemic heart disease later in life.
References:
- Coppage, K.H. and Sibai, B.M. Hypertension Emergencies. In Foley, M.R.., Strong T.H.J and Garite, T.J. editors. Obstetric Intensive Care Manual 2nd edition. Mc Graw-Hill Medical Publishing; 2004.p. 5 1-65
- Seely, E.W. Hypertension in Pregnancy: A Potential Window into Long Term Cardiovascular Risk in Women; 1999
- Minister of Health. Training Manual on Hypertensive Disorder in Pregnancy. National Technical Committee Confidential Enquiries into Maternal Deaths. 2000
- Collier, J., Longmore, M. and Brown, T.D. Oxford Handbook of Clinical Specialties, Oxford University Press; 2001.
- Clinical Practice Guidelines Management of Hypertension. 3rd edition. Ministry of Health Malaysia, Academy of Medicine of Malaysia and Malaysian Society of Hypertension; 2008.
- Magee, L.A., Onstein, M.P. and Dadelszen, P.V. Management of Hypertension in pregnancy. British Medical Journal. 1999; 318 (7194): 1332-1336
- Hannaford P., Perry and Hirsch S. Cardiovascular Sequelae of Toxemia of Pregnancy. Heart, 1997; 77: 154-158.
- Rahman, L.A., Hairi, N.N., and Salleh (2008), association between Pregnancy Induced Hypertension and Low Birth Weight; A population based Control Case Study, Asia Pacific Journal of Public Health. 2008; 20 (2):152-158.
Tags: chronic hypertension, eclampsia, essential hypertension, gestational hypertension, hypertension, low birth weight, lpacental hypoperfusion, pre eclampsia
Technorati Tags: chronic hypertension, eclampsia, essential hypertension, gestational hypertension, hypertension, low birth weight, lpacental hypoperfusion, pre eclampsia
I had gestational hypertension during 2nd month of pregnancy which changed into eclampsia. My whole 9 months was very difficult but atlast succeeded in delivery healthy child.