Maternal and neonatal outcomes in full-term pregnancies of very advanced maternal age: a Japanese single-center retrospective cohort study.

BACKGROUND

Advanced maternal age (AMA), defined as pregnancy in people aged ≥ 35 years, is associated with an increased risk of adverse perinatal outcomes. Although the outcomes of AMA pregnancies have been reported, detailed information on the specific outcomes in pregnant individuals aged ≥ 45 years, particularly those reaching full term, remains limited. Therefore, this study aimed to investigate the perinatal outcomes of full-term pregnant individuals aged ≥ 45 years.

METHODS

We conducted a retrospective cohort study involving full-term pregnant individuals aged ≥ 35 years who attempted vaginal delivery at our facility between January 2019 and December 2023. Participants were categorized into the AMA (35-39 years, n = 947), moderate AMA (40-44 years, n = 387), and very AMA (≥ 45 years, n = 34) groups. The primary outcomes included maternal outcomes, such as intrapartum cesarean delivery (CD) rate and indications, blood loss, and additional interventions (e.g., uterine artery embolization [UAE]). Secondary outcomes included neonatal outcomes such as birth weight, Apgar score, umbilical artery pH, need for respiratory support, and neonatal intensive care unit (NICU) admission within 24 h of birth.

RESULTS

The intrapartum CD rate increased significantly with age (AMA: 17.0%, moderate AMA: 27.1%, very AMA: 35.3%; p < 0.01). However, more than half of the deliveries were vaginal, even in the very AMA group. No significant differences in intrapartum CD indications were found between the groups. The amount of blood loss was significantly higher in the moderate AMA group than in the other groups (p < 0.001). UAE and cesarean hysterectomy incidences showed no significant differences across the groups (p = 0.52 and p = 0.78, respectively). Regarding neonatal outcomes, no significant differences in birth weight were observed, along with low Apgar score, low umbilical artery pH, need for respiratory support, or NICU admission within 24 h of birth between the groups (p = 0.61, p = 0.62, p = 0.52, p = 1.00, and p = 0.44, respectively).

CONCLUSIONS

Although the risk of intrapartum CD increases in pregnant individuals aged ≥ 45 years, those delivering at full term have neonatal outcomes similar to those of younger AMA pregnancies. Importantly, nearly two-thirds of this cohort achieved vaginal delivery. This information may be helpful for consultations with pregnant individuals aged ≥ 45 years in the clinical setting.