In a significant shift since 1998, the rate of triplet births and births of a higher order, like quadruplets and sextuplets, plummeted by 62% in the United States in 2023, according to a recent report from the Centres for Disease Control and Prevention (CDC).

The report revealed that the decline is more pronounced among white mothers, who experienced a 71% drop, while Hispanic mothers saw a 25% decrease, the New York Post reported.

Meanwhile, the birth rate for black mothers increased by 25%.

But what caused this dramatic decline in the numbers?

According to the report, the practice of implanting multiple embryos during in vitro fertilisation (IVF) often leads to higher chances of pregnancy and is a cost-effective approach.

However, it carries heightened risks for mothers and infants, including premature births, low birth weight, and other serious health complications like ectopic pregnancy, stillbirth, high blood pressure and gestational diabetes.

“This decline in triplet and higher-order births over the last 25 years has been associated with changes to guidance related to the number of embryos transferred during assisted reproductive technology use,” the report read.

Previously, women under the age of 35 were limited to three embryo transfers, while those over 40 or with multiple failed IVF cycles could implant up to five, according to the guidelines issued by the American Society for Reproductive Medicine (ASMR) and the Society for Assisted Reproductive Technology in the 1990s.

However, ASRM now advises transferring primarily one embryo for most cases. For women over 40, recommendation is to implant a maximum of four untested early-stage embryos at once.

“These guidelines have evolved as the technology has evolved,” Dr Micah Hill — president of the Society for Assisted Reproductive Technology, who was not involved in the new report — told CNN.

“I think it’s been successful in making fertility treatments safer, which is really what we care about when we’re talking about reducing these higher-order multiples,” Hill added.

The decision is ultimately left to the physician and patient.