Recommendations and resources
1) Do not test for inherited thrombophilia for placental mediated complications.
While older retrospective studies suggested that inherited thrombophilia is associated with adverse pregnancy outcomes such as stillbirth, recurrent miscarriage and placental abruption, more recent and more rigorous studies have either failed to find an association or have found only a weak association. Moreover, the association is a moot point as there is now good quality evidence from randomised controlled trials that low-molecular-weight heparin does not significantly reduce the rate of placental mediated complications.
2) Do not do repeat testing for proteinuria in established pre-eclampsia.
Measuring proteinuria is useful as a diagnostic but not as a prognostic criterion for pre-eclampsia. This is because the level of proteinuria does not correlate with the severity of maternal complications in women with pre-eclampsia, nor are these levels useful in determining the timing of delivery. Thus, repeat testing for proteinuria in managing established pre-eclampsia is not recommended, particularly given the availability of superior prognostic models.
3) Do not undertake methylenetetrahydrofolate reductase (MTHFR) polymorphism testing as part of a routine evaluation for thrombophilia in pregnancy.
Patients with the thermolabile variant of the methylenetetrahydrofolate reductase (MTHFR) polymorphism are at higher risk of hyperhomocysteinaemia which has been associated with venous thrombosis. However, these associations appear to hold only in countries lacking grain products nutritionally fortified as a public health measure. Moreover, homozygous variants are found in up to 15 per cent of some populations, so that detection of this variant would lead to many women undergoing complex counselling unnecessarily and may also be a cause of distress. Polymorphism is not more prevalent in women with pregnancy-associated venous thromboembolism and testing for this polymorhism is not recommended as part of a routine evaluation for thrombophilia in pregnancy.
4) Do not measure erythrocyte sedimentation rate (ESR) in pregnancy.
Measuring the erythrocyte sedimentation rate (ESR) is a non-specific test to identify inflammation. An elevated result indicates inflammation but does not indicate where it is in the body or the cause. The normal range outside of pregnancy in women aged 18–50 is <20mm/h. One study found that levels varied from 4-70mm/hr and another found a range from 4-112mm/ hr, with levels being affected by gestational age and haemoglobin concentration. This is likely to reflect normal changes in pregnancy, meaning that testing for an elevated ESR does not sufficiently differentiate between healthy pregnant women and those who may be suffering from inflammatory diseases.