HELLP syndrome at <23 weeks' gestation: a systematic literature review

We performed a systematic review to evaluate the clinical presentation and maternal and fetal outcomes in pregnancies with early-onset HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome.

PubMed, Ovid MEDLINE, Scopus, CINAHL, Cochrane Library, and ClinicalTrials.gov were queried from inception through January 1, 2023 with the following terms: "HELLP syndrome," "HELLP," "hemolysis, elevated liver enzymes, low platelets," "hemolysis, elevated liver enzymes, low platelets syndrome," "pre-viable," "peri-viable," "previable," "periviable," "first trimester," "second trimester," "before 23 weeks," "<23 weeks," "<23 week gestation," and "before 23 weeks gestation." We also included an additional case from our institution.

Abstracts, unpublished studies, and review articles were excluded, yielding 46 studies that met our inclusion criteria.

Two reviewers (N.S.I. and M.H.M.) performed the study selection and subsequent data extraction independently, after which the results were reviewed together. PRISMA guidelines were followed, and our study was registered at PROSPERO (CRD42021292692).

A total of 55 patients had 58 pregnancies complicated by early-onset HELLP syndrome, including 3 with recurrent HELLP. The most common presenting signs/symptoms were abdominal pain (35/45; 78%), hypertension (32/49; 65%), nausea/vomiting (16/45; 36%), headache (13/45; 29%), and edema (8/45; 18%). Lactate dehydrogenase ≥600 IU/L was observed in 21 of 31 (68%) cases, whereas liver enzyme abnormalities and thrombocytopenia were reported in 48 of 51 (94%) and 50 of 54 (93%) cases, respectively. Maternal complications were encountered in 25 of 56 (45%) cases. The most common complications were hepatic (13/56; 23%), central nervous system-related (11/56; 20%), and respiratory (11/56; 20%). In 36 of 57 (63%) cases, pregnancy was terminated. Of the 21 continued pregnancies, early fetal death (at <20 weeks' gestation) was reported in 10 (48%), stillbirth in 6 (28%), and neonatal demise in 2 (10%). Living neonates were reported in 3 of 21 (14%) cases, all delivered at 23 weeks. The perinatal mortality rate was 73% (8/11). One case (2%) reported maternal death. Antiphospholipid syndrome was diagnosed in 14 of 29 (48%) cases.

Early-onset HELLP syndrome presents with symptoms similar to those observed in later gestation. Maternal complications are life-threatening, with the most common complications being hepatic, central nervous system-related, and respiratory. Fetal outcomes are poor.