Pre-eclampsia is uniquely a disease occurring in the second half of pregnancy (after 20 weeks gestation), and conventionally, characterised by pregnancy-induced hypertension, with proteinuria and often with oedema (1,2):

• NICE state that pe-eclampsia is new hypertension presenting after 20 weeks with significant proteinuria (2)
  • significant proteinuria is diagnosed if the urinary protein:creatinine ratio is greater than 30 mg/mmol or a validated 24-hour urine collection result shows greater than 300 mg protein.

• hypertensive disorders during pregnancy may also result in substantial maternal morbidity
  • a UK study reported that one-third of severe maternal morbidity was a consequence of hypertensive conditions
  • a study from one region of the UK reported that 1 in 20 (5%) women with severe pre-eclampsia or eclampsia were admitted to intensive care
• hypertensive disorders also carry a risk for the baby (2)
  • the most recent UK perinatal mortality report, 1 in 20 (5%) stillbirths in infants without congenital abnormality occurred in women with pre-eclampsia
  • the contribution of pre-eclampsia to the overall preterm birth rate is substantial;
    • 1 in 250 (0.4%) women in their first pregnancy will give birth before 34 weeks as a consequence of pre-eclampsia and 8-10% of all preterm births result from hypertensive disorders
    • half of women with severe pre-eclampsia give birth preterm
    • small-for-gestational-age babies (mainly because of fetal growth restriction arising from placental disease) are common, with 20-25% of preterm births and 14-19% of term births in women with pre-eclampsia being less than the tenth centile of birth weight for gestation

NICE suggest that (1):

• blood pressure measurement and urinalysis for protein should be carried out at each antenatal visit to screen for pre-eclampsia
• at the booking appointment, the following risk factors for pre-eclampsia should be determined:
  • age 40 years or older
  • nulliparity
  • pregnancy interval of more than 10 years
  • family history of pre-eclampsia
  • previous history of pre-eclampsia
  • body mass index 30 kg/m2 or above
  • pre-existing vascular disease such as hypertension
  • pre-existing renal disease
  • multiple pregnancy
  • more frequent blood pressure measurements should be considered for pregnant women who have any of the above risk factors
• the presence of significant hypertension and/or proteinuria should alert the healthcare professional to the need for increased surveillance
• hypertension in which there is a single diastolic blood pressure of 110 mmHg or two consecutive readings of 90 mmHg at least 4 hours apart and/or significant proteinuria (1+) should prompt increased surveillance
• if the systolic blood pressure is above 160 mmHg on two consecutive readings at least 4 hours apart, treatment should be considered
• all pregnant women should be made aware of the need to seek immediate advice from a healthcare professional if they experience symptoms of pre-eclampsia. Symptoms include:
  • severe headache
  • problems with vision, such as blurring or flashing before the eyes
  • severe pain just below the ribs
  • vomiting
  • sudden swelling of the face, hands or feet

See the diagnosistic criteria in the linked article.

• advice from the UK National Screening Committee on antenatal screening for pre-eclampsia...click here

Reference:

1. NICE (2008). Antenatal care
2. NICE (August 2010). Hypertension in pregnancy - the management of hypertensive disorders during pregnancy