A systematic review and meta-analysis conducted in accordance with PRISMA guidelines assessed whether first-trimester placental volume (PV) and vascular indices are associated with subsequent development of preeclampsia (PE) or gestational hypertension (GH). The results were published in the European Heart Journal Quality of Care and Clinical Outcomes. PubMed, Embase, and Web of Science were searched from inception to March 2025. Cross-sectional, cohort, and case-control studies evaluating PV or vascular indices between 11 and 14 weeks of gestation were included.

Thirty-eight studies met inclusion criteria, with ultrasound performed at 11–14 weeks in 36 studies. Compared with normotensive controls, pregnancies that developed PE had significantly lower PV (mean difference [MD] −12.61; 95% CI −19.05 to −6.17; p=0.0001). Lower PV was also observed in early-onset PE (MD −20.61; 95% CI −27.56 to −13.66; p<0.00001) and late-onset PE (MD −11.89; 95% CI −17.00 to −6.78; p<0.00001).

Additionally, vascular indices were lower in PE, including vascularization index (MD −4.69; 95% CI −6.40 to −2.98; p<0.00001), flow index (MD −4.83; 95% CI −6.59 to −3.07; p<0.00001), and vascularization flow index (MD −1.98; 95% CI −2.59 to −1.37; p<0.00001). No differences were reported for gestational hypertension.

First-trimester PV and vascular indices were lower in pregnancies that subsequently developed PE. Prospective validation and standardized measurement are required to clarify clinical applicability.