Adverse maternal and neonatal outcomes in extremely young mothers (≤ 17 years) versus women aged 20–35 years: a retrospective cohort study in Thailand

To compare maternal and neonatal outcomes between extremely young mothers (≤ 17 years) and women aged 20–35 years delivering at a Thai tertiary center. We conducted a retrospective cohort at Siriraj Hospital, Bangkok, Thailand, using delivery records from January 2014 to December 2023. Women were categorized into 2 groups: extremely young (≤ 17 years) and comparison (20–35 years). Maternal characteristics, pregnancy complications, delivery outcomes, and neonatal outcomes were extracted and analyzed using appropriate statistical tests. Among 2333 deliveries, 1154 were to extremely young mothers and 1179 to women aged 20–35 years. Extremely young mothers were more often primigravida and nulliparous. They had higher rates of anemia (30.7% vs 18.7%), a positive Venereal Disease Research Laboratory test (4.1% vs 1.0%), and illicit drug use (3.1% vs 0.3%; all P < 0.001). They were also more likely to deliver preterm (22.7% vs 15.1%), have low birth weight infants (23.6% vs 15.6%), and experience stillbirth (1.4% vs 0.3%). Conversely, gestational diabetes mellitus (11.7% vs 0.6%), postpartum hemorrhage (3.6% vs 1.1%), and cesarean delivery (50.7% vs 17.6%) were more frequent in women aged 20–35 years (all P < 0.05). Additionally, placenta previa occurred only in this age group (0.8%; P = 0.002). Extremely young mothers have increased risks of anemia, preterm birth, low birth weight, and stillbirth. Women aged 20–35 years are more affected by gestational diabetes, placenta previa, postpartum hemorrhage, and cesarean delivery. Therefore, age-specific antenatal care and targeted interventions for adolescent pregnancy are warranted.