Mothers who are still children themselves often haven't completed their physical or psychological growth and face higher risk of severe bleeding, anaemia, miscarriage, obstructed labour and premature birth, along with a greater likelihood of a low-weight or unhealthy infant.
Sima says she is still feeling the effects of bearing children so young. "During my pregnancy, I fainted several times because my blood pressure dropped very low.
I always have a headache. My kidneys ache.
I feel like a 70-year-old person," says Sima, a mother of four.
Shabnam says families often resist caesarean section, believing they limit future pregnancies.
Two young mothers in her care recently died in childbirth because their husbands refused to permit one.
A report by the UN's Office for the Coordination of Humanitarian Affairs put Afghanistan's maternal mortality rate at 600 per 100,000 live births, compared with 16 in Iran, 155 in Pakistan, and 12 in the UK.
The report cites restrictions on women in healthcare and a shortage of rural health workers, and calls investment in education and female health staff vital.
Sima is one of more than 2.2 million Afghan girls who have been barred from education above the sixth grade (about 12 years) since the Taliban returned to power.
Many are now forced into marriage and premature motherhood.
The Afghanistan Human Rights Center reports that one teacher estimated 70% of girls pushed out of school had been driven into forced marriages, while a smaller survey of 15 such girls found 66% of them were under 18.
