Definition of Advanced Maternal Age
Advanced maternal age (AMA) is traditionally defined as pregnancy at age 35 years or older at the estimated date of delivery 1, 2, 3.
The Evolving Definition
While the threshold of 35 years has been the historical standard, there is ongoing debate about whether this cutoff remains clinically relevant:
The 35-year threshold remains the most widely accepted definition internationally for identifying women who may benefit from enhanced prenatal surveillance 1, 2, 3
Risk increases progressively from age 35 onward, with complications becoming more pronounced as maternal age advances 4
Age 40 years is increasingly adopted as a more clinically significant threshold for adjusting surveillance protocols and determining optimal delivery timing (between 39-40 weeks) 4
Clinical Rationale for the Definition
The age cutoff is based on the observed increase in both maternal and fetal complications:
Maternal risks that increase with AMA include:
- Gestational diabetes
- Hypertensive disorders (preeclampsia/eclampsia)
- Thrombotic complications
- Placenta previa and placental abruption
- Higher cesarean section rates
- Increased maternal mortality 4, 2, 5
Fetal and neonatal risks include:
- Chromosomal abnormalities (particularly aneuploidy)
- Miscarriage
- Stillbirth
- Fetal growth restriction
- Prematurity 4, 5
Important Caveats
AMA is a non-modifiable risk factor that requires recognition for appropriate prenatal care planning 4
Some recent data suggest that with modern obstetric care, many women of advanced maternal age have uncomplicated pregnancies, particularly those without additional medical comorbidities 1, 6
The definition may continue to evolve, with some experts suggesting that age 40 may become the new threshold for "advanced" maternal age as outcomes improve for women in their mid-to-late 30s 6