Resolution of superimposed pre-eclampsia, and improvement in umbilical artery flow in a surviving twin after intrauterine demise of its co-twin

Do Case Reports and Case Series Generate Clinical Discoveries About Preeclampsia? A Systematic Review

Background

Preeclampsia is a leading cause of maternal and perinatal mortality and morbidity. The management of preeclampsia has not changed much in more than two decades, and its aetiology is still not fully understood. Case reports and case series have traditionally been used to communicate new knowledge about existing conditions. Whether this is true for preeclampsia is not known.

Objective

To determine whether recent case reports or case series have generated new knowledge and clinical discoveries about preeclampsia.

Methods

A detailed search strategy was developed in consultation with a medical librarian. Two bibliographic databases were searched through Ovid: Embase and MEDLINE. We selected case reports or case series published between 2015 and 2020, comprising pregnant persons diagnosed with hypertensive disorders of pregnancy, including preeclampsia. Two reviewers independently screened all publications. One reviewer extracted data from included studies, while another conducted a quality check of extracted data. We developed a codebook to guide our data extraction and outcomes assessment. The quality of each report was determined based on Joanna Briggs Institute (JBI) critical appraisal checklist for case reports and case series.

Results

We included 104 case reports and three case series, together comprising 118 pregnancies. A severe presentation or complication of preeclampsia was reported in 81% of pregnancies, and 84% had a positive maternal outcome, free of death or persistent complications. Only 8% of the case reports were deemed to be of high quality, and 53.8% of moderate quality; none of the case series were of high quality. A total of 26 of the 107 publications (24.3%) included a novel clinical discovery as a central theme.

Conclusion

Over two-thirds of recent case reports and case series about preeclampsia do not appear to present new knowledge or discoveries about preeclampsia, and most are of low quality.

Recovery of second trimester pre-eclampsia after fetal reduction of a triplet

Women with a multiple pregnancy are at increased risk of developing hypertensive disorders of pregnancy. We describe a case of a dichorionic triamniotic triplet pregnancy complicated by severe hypertension, proteinuria and maternal symptoms, fitting with the diagnosis of pre-eclampsia, apart from the early gestational age of only 16 weeks. After reduction of the monochorionic pair, the disease resolved and pre-eclampsia was diagnosed again at 30 weeks of gestation, resulting in a delivery on maternal indication at 33 weeks of gestation. In a review of the literature, we found six papers including eight cases on multifetal pregnancy reduction on maternal indication. Multifetal pregnancy reduction resulted in a prolongation of pregnancy of two to 21 weeks and may be considered in extreme early onset pre-eclampsia in dichorionic multiple pregnancies.

Triploid twin gestation with single fetal demise associated with partial mole and pre-eclampsia

Both partial mole and twin gestation are conditions associated with the risk of the early onset of pre-eclampsia. In cases of twin gestation, the death or selective termination of a severely growth-restricted fetus may lead to the reversal of maternal pre-eclampsia because of the involution or death of the pathological placenta, as has been reported by some authors. This case demonstrates that in a twin triploid gestation, in spite of the demise of one of the fetuses, the respective partial molar placenta can continue to grow and may contribute to the development or to the worsening of the pre-eclampsia.

Do preeclampsia symptoms resolve after intrauterine death of a fetus?

We present two cases of twin pregnancies without resolution of preeclamptic symptoms after intrauterine death of one twin.

Case 1:

A nulliparous woman aged 37 years was referred at 26 weeks of gestation because of arterial hypertension, edema, and growth restriction in one twin. Three weeks later the restricted twin died. During the following three weeks, ultrasound examinations showed a reduced growth velocity of the surviving fetus and reversed umbilical flow. At the end of the 34^th week of gestation, cesarean section was performed and a healthy female infant was delivered.

Case 2:

A nulliparous woman aged 33 years with a 27-week twin pregnancy was referred because of arterial hypertension and discordant growth. The restricted twin died at 31 weeks of gestation. Following the death, within two weeks the growth of the co-twin started to slow down and reversed end diastolic flow presented. At the end of the 33^rd week of gestation, cesarean section was performed and a healthy female infant was delivered.

The interesting point of these cases was the secondary effects on the co-twins. During the time after intrauterine deaths of one twin, the surviving fetuses started to show a reduced growth velocity and reversed umbilical flow and mothers had increased blood pressure and proteinuria again. We think that both cases are evidence of late on-set systemic maternal effects (such as systemic maternal endothelial activation and/or systemic maternal inflammatory response) depends on preeclampsia.