Advanced Maternal Age and Abnormal Cord Insertion: A Prospective Cohort Study Exploring Placental Morphogenesis

Abstract Background Advanced maternal age (AMA, ≥35 years) has become increasingly common, with corresponding rises in obstetric complications. Abnormal placental cord insertion (PCI), including marginal (MCI) and velamentous cord insertion (VCI), has been linked to adverse perinatal outcomes, yet its relationship with AMA remains poorly defined. This study examined whether AMA is associated with abnormal PCI morphology in singleton pregnancies. Methods A secondary analysis was conducted using 564 prospectively collected placentas from University Hospital Limerick (2016). Eligible participants had singleton pregnancies ≥24 weeks. Cord insertion was digitally measured using ImageJ and classified as central, eccentric, marginal (≤2 cm from placental edge) or velamentous (membranous insertion). Primary exposure was maternal age ≥35 years. Logistic regression estimated adjusted odds ratios (aOR) for AMA and abnormal PCI after adjustment for parity, BMI, smoking, ART use, prior cesarean and preterm delivery. Results Among 564 women, 36% (n=204) were of AMA, with mean maternal age 32 ± 5.5 years. Overall, VCI prevalence was 3.7% (n=21) and MCI 7.6% (n=43). AMA women had higher rates of both VCI (5.4% vs. 2.8%) and MCI (9.3% vs. 6.7%) compared with younger counterparts. Adjusted analyses showed non-significant trends toward increased risk (VCI: aOR 1.6, 95% CI 0.9–2.8; MCI: aOR 1.4, 95% CI 0.8–2.5). Sensitivity analyses stratified by parity and ART status confirmed the directional consistency. Interobserver reliability for cord classification was high (κ = 0.89). Despite limited statistical power, findings support a biological gradient suggesting that AMA may predispose to abnormal PCI via vascular and trophoblastic ageing mechanisms. Conclusion While associations between AMA and abnormal PCI did not reach significance, consistent trends highlight potential age-related placental morphogenic vulnerability. Larger multicentre cohorts integrating prenatal imaging are warranted to validate these preliminary observations.