Editorial in the Icelandic Medical Journal: “Preeclampsia” by Alexander Kristinn Smárason

“It is estimated that 700 women die every day worldwide in connection with childbirth. The highest mortality rates are found in Central Africa, with 450 deaths per 100,000 births, while the lowest rates are in the Nordic countries, with five deaths per 100,000 births. After hemorrhage and infection, preeclampsia is the most common cause of maternal death globally, whereas in the Nordic countries thromboembolism and preeclampsia are the leading causes.

Significant changes have been made to antenatal care and the management of preeclampsia, based on international guidelines. Diagnostic criteria have been expanded, as proteinuria is no longer required for diagnosis. Screening for risk factors is now performed, and women at risk are advised to take 150 mg of acetylsalicylic acid from weeks 12 to 36 of pregnancy in order to reduce the incidence of early-onset preeclampsia. Labour is induced in women with preeclampsia no later than 37 weeks’ gestation, or immediately if the diagnosis is made after that point. Administration of magnesium sulfate is recommended for women with severe preeclampsia and to prevent recurrent seizures.

It is not certain that these changes have affected outcomes within our healthcare system, which has long provided strong, free maternity services and antenatal care. It is therefore important to monitor whether changes have occurred in the number of diagnoses, cases of severe preeclampsia and eclampsia, inductions of labour, perinatal mortality, and maternal mortality.

Eclampsia is the oldest known manifestation of preeclampsia and the most severe. It is therefore encouraging to see, in this issue of the Icelandic Medical Journal, an article examining the incidence of eclampsia at Landspítali University Hospital from 1982 to 2022. In total, 33 women experienced eclampsia, corresponding to 1 in 3,610 births, which is a low incidence compared with, for example, the Nordic countries, where the incidence has been estimated at 1 in 2,000. There was no significant difference in incidence between the first and second halves of the study period, suggesting that the incidence was already very low 40 years ago and that the aforementioned changes have not had a measurable impact in reducing cases further. No woman died following eclampsia, and only one infant, an extremely premature baby, died during the perinatal period. Magnesium sulfate was generally administered in the later years of the study period.

A major strength of the study is that all cases were reviewed in order to assess the reliability of diagnostic coding and confirm whether the cases truly represented eclampsia. This is particularly important in a country such as Iceland, where incidence is low and incorrect diagnoses are therefore more likely to have a substantial impact.

The main limitation is that the study was restricted to cases at Landspítali. Women at risk may have been transferred there, and some may also have been transferred after experiencing seizures. It is known that women experienced eclampsia elsewhere in the country during the same period. Consequently, the underlying population is not clearly defined, and incidence figures for Iceland are therefore imprecise. This serves as a reminder to researchers studying rare diseases that are not universally referred to Landspítali, to include the entire country whenever possible so that meaningful international comparisons can be made.

Although the findings suggest that Iceland has strong antenatal care and maternity services, it is important that we remain vigilant, as nine of the 33 women had not been diagnosed with preeclampsia when they experienced eclampsia, and maternal deaths due to preeclampsia are known to have occurred during the period under review.

The next step in this field in Iceland is to investigate and determine whether more targeted screening should be introduced for women at risk of preeclampsia by adding uterine artery Doppler measurements and biochemical markers. Studies from Denmark, where the incidence of preeclampsia is similarly low to Iceland, suggest that this more targeted screening improves outcomes and is cost-effective.”