A 31-year-old woman with a history of type 1 diabetes mellitus and Basedow disease became pregnant for the first time. Her pre-pregnancy body mass index was 25.5 kg/m2. She was referred to our department at 33 weeks of gestation due to mildly elevated blood pressure and was hospitalized at 34 weeks and 2 days for the development of hypertension and new-onset proteinuria. After hospitalization, she was kept at rest without the use of anti-hypertensive drugs, and her blood pressure and proteinuria decreased spontaneously. Additionally, we confirmed that serum soluble fms-like tyrosine kinase-1 (sFlt-1)/placental growth factor (PlGF) ratio was within normal range (sFlt-1, 2097 pg/mL;PlGF, 210 pg/mL; ratio 9.98) at 34 weeks and 5 days. There were no signs of elevated serum creatinine, low platelet, hyperuricemia, and elevated liver transaminases, which are associated with preeclampsia (PE). She subsequently gave birth at 39 weeks and 3 days, with the child’s birth weight being 3072 g. Considering her clinical course and serum biomarkers, we concluded that her diagnosis was likely not PE.
PE is defined as new-onset hypertension after 20 weeks of gestation and is associated with placental and maternal endothelial dysfunction. It alters angiogenic factors such as serum sFlt-1 and PlGF, which serve as biomarkers for PE. In Japan, insurance covers serum sFlt-1/PlGF measurement between 18 and 36 weeks of gestation when hypertensive disorders of pregnancy (HDP) are suspected. Eligibility requires at least one of the following risk factors: systolic blood pressure ≥ 130 mmHg or diastolic blood pressure ≥ 80 mmHg, proteinuria, clinical symptoms or laboratory findings suggestive of preeclampsia, intrauterine growth restriction and laboratory findings indicative of intrauterine growth restriction. In our case, despite the presence of two risk factors (hypertension and proteinuria) were present, the sFlt-1/PlGF ratio was not elevated.
According to the 2020 guidelines of the American College of Obstetricians and Gynecologists (ACOG), proteinuria is generally diagnostic for PE [1]. However, in our case, considering the sFlt-1/PlGF ratio and clinical course lowered the likelihood of PE. ACOG also recommends low-dose aspirin (LDA) for patients at high risk of recurrent PE [2]. Since a low sFlt-1/PlGF ratio was confirmed, intensive LDA administration may not be necessary in future pregnancies.
Serum sFlt-1/PlGF ratio 38 or lower predicts a short-term absence of PE in women clinically suspected of condition [3]. The ratio is also utilized at different stages of pregnancy. In the first trimester, risk assessment incorporating PlGF helps determine the need for LDA [4]. Additionally, a multicenter randomized trial is planned to evaluate whether scheduling deliveries based on the sFlt-1/PlGF ratio at 35 to 37 weeks of gestation can reduce the incidence of term PE.5 Furthermore, the serum sFlt-1/PlGF ratio may aid in managing pregnant women with transient proteinuria and hypertension by guiding LDA use and informing interconception care planning.
Declarations
Conflict of interest
The authors declare no competing interests.
Research involving human participants and/or animals
This article does not contain any studies with human participants performed by any of the authors.
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Informed consent was obtained from all individual participants included in the study.
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