An increasing number of babies are delivered by Caesarean section, according to research from 169 countries published in the Lancet. Around the globe, the figure is nearly 30 million babies — 21 percent. That number, from 2015, represents a near doubling of C-section births worldwide since 2000, when there were 16 million such deliveries, or 12 percent of live births.

Medical groups generally urge a C-section when it is medically necessary because of the mother’s health problems, threats to the baby’s health, a multiple birth or the large size or abnormal position of the baby. But childbirth experts say ­C-sections would account for about 10 to 15 percent of the babies delivered if they were done only because of complications. In 106 of the 169 countries, C-section rates were “well above what is expected on the basis of obstetric indications.”

In 15 countries, the procedure accounted for more than 40 percent of births. The research noted that C-sections tended to be underused in poor countries and overused in higher-income countries. In North America, the rate of C-section births increased from 24 percent to 32 percent in the 15-year span, according to the new research. In the United States, the lowest rate was in New Mexico (18 percent) and the highest in New Jersey (33 percent).

A C-section delivery is generally safe for both mother and baby. But it does come with some risk because it involves incisions in the woman’s abdomen and uterus. Babies born by C-section sometimes have breathing problems for a few days after birth. Women who have a C-section have an increased risk for complications in future pregnancies, including problems related to the placenta and heavy bleeding. Having a C-section, however, does not rule out having a vaginal birth in the future.

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