SCREENING for placental growth factor (PlGF) at the time of gestational diabetes testing in midpregnancy is strongly associated with the risk of early preterm birth before 34 weeks’ gestation.
Early preterm birth poses a significant risk for adverse neonatal outcomes, yet there is currently no universal screening strategy to identify those at the highest risk. This cohort study investigated the potential of midpregnancy PlGF testing as a predictive tool for early preterm birth. Conducted at an urban tertiary care centre from 2020 to 2023, the study involved 9,037 unselected, singleton pregnancies, where PlGF levels were measured during routine gestational diabetes screening at 24 to 28 weeks’ gestation.
A PlGF level below 100 pg/mL was significantly associated with an increased likelihood of early preterm birth, demonstrating an area under the curve (AUC) of 0.80 (95% CI, 0.75-0.85). Among the 156 pregnancies (1.7%) that resulted in early preterm birth, over 50% of iatrogenic preterm births and 30% of stillbirths were linked to low PlGF levels. The relative risk for early preterm birth in those with low PlGF was 79.4 times higher (95% CI, 53.4-115.1), while the AUC for iatrogenic preterm birth was 0.90 (95% CI, 0.85-0.94). More than half of individuals with low PlGF levels delivered within 50 days of testing, indicating its potential as a predictive marker. The test exhibited high specificity (99.5%) and a negative predictive value of 98.9%, suggesting it could effectively identify those unlikely to experience early preterm birth.
These findings highlight midpregnancy PlGF testing as a promising clinical tool for identifying individuals at the highest risk of early preterm birth, particularly in iatrogenic cases. Integrating this screening into routine prenatal care could allow for targeted monitoring and timely interventions, such as increased surveillance, antihypertensive management, or planned delivery at tertiary care centres. Given its simplicity and alignment with existing gestational diabetes screening, PlGF testing could be widely implemented without additional burdens on healthcare systems. Future research, including randomised trials, is needed to assess the impact of universal PlGF screening on maternal and neonatal outcomes and to refine intervention strategies based on risk stratification.
Katrina Thornber, EMJ
Reference
Gladstone RA et al. Midpregnancy placental growth factor screening and early preterm birth. JAMA Netw Open. 2024;7(11):e2444454.
