Risk factors

The possibility of developing pre-eclampsia during pregnancy is higher in women with the following risk factors (1):

• at least one high risk factors
• history of hypertensive disorders during previous pregnancy
• chronic kidney disease
• autoimmune disease e.g. – systemic lupus erythematosus, antiphospholipid syndrome
• type 1 or 2 diabetes
• chronic hypertension
• thrombophilic disease
• at least two moderate risk factors
• primiparity - immediately confers medium risk (also first pregnancy with a new partner)
• multiple pregnancy
• family history of pre-eclamptic toxaemia or eclampsia
• BMI of 35 kg/m2 or greater at the first visit
• age 40 years or older
• interval since last pregnancy of more than 10 years (1)
• change of partner - the increased risk following change of partner and the inverse association between risk and duration of sexual cohabitation before conception implicate an immunological basis of this condition (2)

The maternal risk of development of this condition is determined by the number of risk factors that a mother possesses:

• low risk (1:1000 pregnancies) if no risk factors
• medium risk (1:10 pregnancies) if primigravida
• high risk (1:5 pregnancies) if multiple risk factors

Fetal risk factors pertain principally to those associated with increased placental size:

• multiple pregnancy
• hydatidiform mole
• hydrops

Reference:

• (1) NICE (August 2010). Hypertension in pregnancy - the management of hypertensive disorders during pregnancy
• (2) Williams B, Poulter NR, Brown MJ, Davis M, McInnes GT, Potter JF, et al. Guidelines for management of hypertension: report of the fourth working party of the British Hypertension Society, 2004—BHS IV. J Hum Hypertens 2004;18: 139-8
• Ramsey LE et al (1999). Guidelines for the management of hypertension: report of the third working party of the British Hypertension Society, 1999. J Hum Hypertens, 13, 569-92