The number of women who deliver babies by Caesarean section has almost doubled worldwide since 2000, to around 21%.
That's significantly more than the medically necessary 10 to 15 percent, the researchers said.
When complications develop, C-sections can save the lives of mothers and their babies. But the operation is not risk-free and fraught with difficulties in future births.
"The large increases in C-section use – mostly in richer settings for non-medical purposes – are affected because of the associated risks for women and children," said Drs. Marleen Temmerman, lead author of three studies published on October 1
Temmerman is a professor of obstetrics and gynecology at Aga Khan University in Nairobi, Kenya.
The study found that global C-profiles increased by nearly 4% per year between 2000 and 2015. This represents 16 million of the 132 million live births in 2000 and 30 million of the 141 million live births in 2015.
The fastest increase (6%) was in South Asia, where researchers said C-section shipments were under-utilized in 2000, but overused 15 years later.
C profiles have also been overused in the US, Canada, Western Europe, Latin America and the Caribbean, where rates increased by about 2 percent per year during the period under review from 2000 to 2015.
In North America alone, the C-share births during this period increased from about 24% to 32%, according to the study.
Fifteen nations, including Mexico and Cuba, had C-Section rates that surpassed 40%.
Some women opt for elective caesarean sections because they can skip the pain and uncertain timing of natural work. A C-section is medically necessary if complications such as bleeding, high blood pressure or the baby is in an abnormal position in the womb and endangers the mother or child.
But the procedure is not available to many women in low-income countries and has been over-utilized in many middle and high-income countries, the researchers found.
Six out of ten nations have too many C sections and a quarter too few, the study found. In addition, there are huge differences between rich and poor, public and private sectors and between regions, researchers say.
"In cases of complications, C-profiles save lives, and we need to increase accessibility in poorer regions. C-sections are universally available, but we should not overuse them," Temmerman said in a press release.
For the three studies, researchers used data from 169 countries in the World Health Organization and UNICEF databases. One study looked at disparities around the world.
A second concerned the damage of overuse and malnutrition of Cesarean section and the third way to prevent unnecessary.
The publication of the three studies coincided with their presentation at a meeting of the International Federation of Gynecology and Obstetrics, which began on Sunday in Rio de Janeiro, Brazil.