Thailand has the second highest rate of mid-late teenage pregnancy in the entire world, according to Office of Welfare Promotion, Protection and Empowerment of Vulnerable Groups deputy chief Samatchai Chomvinya.
South Africa had the highest rate, according to a report from the Social Development and Human Security Ministry.
About 70 Thai women out of every 1,000 aged 15-19 - or about 7% - already have children, Mr Samatchai said.
World Health Organisation figures show the global average number of pregnancies for every 1,000 girls in the 15-19 age group is 65. In Asia it is 56, but it rises to 70 in Thailand.