Compared with deliveries to patients aged 20-54 years, deliveries to patients aged 11-14 years were associated with increased risk for severe maternal morbidity (aOR 1.73, 95% CI 1.49-2.00), hypertensive disorders of pregnancy (aOR 1.79, 95% CI 1.71-1.88), and postpartum hemorrhage (aOR 1.37, 95% CI 1.27-1.49).
I can’t even find data for kids as young as 9, because it’s such a rare and obviously bad situation.