Triplets are becoming less common in the United States. Here’s why

CNN
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The birth of triplets, quadruplets, and even more is becoming increasingly rare in the United States.

According to the study: The rate of triplet and higher order births in the U.S. decreased by 62% between 1998 and 2023. report released Thursday by the U.S. Centers for Disease Control and Prevention. The greatest declines in rates were observed among mothers aged 30 and older.

The decline appears to be related to strengthening guidelines on the number of embryos transferred during assisted reproductive technologies such as in vitro fertilization, known as IVF, wrote researchers at the CDC’s National Center for Health Statistics.

There are couples greater chance of having twinstriplets or more babies in one pregnancy when using assisted reproductive technology, as these infertility treatments may involve transferring multiple embryos into the uterus in the hope of getting pregnant.

A larger number of embryos not only increases the likelihood of a viable pregnancy, but increases the risk that the pregnancy may involve more than one fetus – and therefore twins, triplets or more.

“Monitoring trends in higher-order triplet and multiple births is important because women with triplet/+ pregnancies have a higher risk of complications during pregnancy and their infants have a higher risk of preterm birth and infant death,” Joyce Martin, researcher at National Center for Health Statistics and lead author of the report, said in an email.

As infertility treatments became more popular after the 1980s, the rate of multiple births increased, said Dr. Micah Hill, president of the Society for Assisted Reproductive Technology, who was not involved in the new report.

In the early 2000s, the American Society of Reproductive Medicine and the Society for Assisted Reproductive Technology began issuing guidelines on the number of embryos that should be transferred in various scenarios. Guidance has been issued to help reduce the risk of complications for women undergoing infertility treatment, including the risk of premature birth.

One sec the new data does not indicate how many multiple births were conceived spontaneously compared to the number of multiple births conceived as a result of assisted reproductive technologies (ART) such as in vitro fertilization, the overall decline is appear to be parallel to the introduction guidelines.

Hill says the guidelines were published in 2004 and updated in 2006, 2008, 2009, 2013, 2017 and 2021.

“If you look at the CDC numbers, you can see that these declines occur every year or two after the guidelines are updated,” Hill said.

“These guidelines have evolved as technology has evolved,” he said. “I think it has made infertility treatment safer, which is what we really care about when we talk about reducing higher-order multipliers.”

Partially the recommendations contained in latest guidelinespublished in 2021, range from recommending the transfer of only one embryo at a time for patients under 35 years of age to recommending no more than four untested early-stage embryos for patients over 40 years of age.

Not only have guidelines for embryo transfer changed over recent decades, possibly leading to a decline in the number of triplets and higher-order births.

There have also been changes in the use of fetal reduction during infertility treatment, a procedure intended to reduce the number of fetuses in cases of pregnancy with triplets or more, said Dr. Amanda Williams, interim medical director of the nonprofit maternal and infant health organization March of Dimes, who was not involved in the NCHS data.

Separately, she called a new NCHS report showing declines in triplet and higher-order multiple births “fantastic news” for maternal and infant health.

“When you have three or more babies at home, you have a significantly increased risk of preterm birth, low birth weight, infant mortality, NICU stays, and on the mother’s side, an increased risk of gestational diabetes, an increased risk of pregnancy complications, hypertensive disorders such as preeclampsia.” – she said. “This is good news for families because triplets and higher-order pregnancies are much riskier for mom and baby.”

In previous years, the rate of triplet and higher-order multiple births in the United States had increased from 37 per 100,000 births in 1980. highest level ever In 1998, the number of births per 100,000 children was about 194, according to the new report.

This “unprecedented increase” was linked to older women giving birth and “increased use of infertility treatments,” Martin and her co-author Michelle Osterman wrote in the report.

“The increase has raised public health concerns due to the greater risk of adverse maternal and child health outcomes in triplet and higher order births compared with twins and singleton births,” they wrote.

But new data showed that since 1998, the rate of triplet and higher-order multiple births in the United States has dropped to about 74 per 100,000 births last year.

From 1998 to 2009, rates dropped, but not significantly, to about 21% to about 154 per 100,000 births in 2009. Rates dropped significantly, by 52%, from 2009 to 2023, according to a new birth certificate-based report. data from the CDC’s National Vital Statistics System. Many people may remember 2009 as the year when Nadya Suleman, known in the media as Octomom, gave birth to eight children in one delivery after undergoing in vitro fertilization.

The new data also showed that the raw number of triplet and higher-order multiple births in the United States dropped by 65% ​​between 1998 and 2023 – from a total of 7,625 births in 1998 to 6,340 births in 2009, to, what is more violent, Last year, 2,653 babies were born.

The new data “reflects what we have seen in terms of fertility care” in the field, said Dr. Asima Ahmad, an endocrinologist and fertility expert who serves as chief medical officer and co-founder of Carrot Fertility, a company that helps employers determine how to increase fertility benefits.

“Embryology laboratories have advanced over the years, allowing them to grow embryos to larger sizes than was possible many years ago. Additional research is also available that may provide more information about embryonic health, Ahmad, who was not involved in the new NCHS report, said in an email. “Given these advances, it is increasingly common for physicians to transfer one embryo at a time to achieve the goal of a singleton pregnancy – the healthiest option for the pregnant woman and baby.”

Analyzing the data by maternal age, researchers found that from 1998 to last year, the birth rate of triplets and higher-order multiple births dropped by 16% for mothers aged 20 to 24; 57% for mothers aged 25 to 29; 77% for mothers aged 30 to 34 and 35 to 39; and 67% for mothers aged 40 and over.

Researchers also found significant racial disparities.

Among white mothers, the rate of triplet and higher-order multiple births dropped 71% from 1998 to last year. Between 1998 and 2023, the number of triplet and higher order births to Latina mothers decreased by 25%.

However, the rate of triplet and higher order births for Black mothers followed a different trend, increasing 21% from 1998 to 2009 and then not changing significantly from 2009 to 2023, for an overall increase of 25% from 1998 to last year.

“The biggest declines have been among white women in their 30s, and that’s the group that has the most access to in vitro fertilization and actual embryo transfer, where the decision can be made to transfer fewer embryos,” March of Dimes’ Williams said.

But there are many other types of assisted reproductive technology that may be factors in these racial disparities, she added.

“When you think about Black women or low-income women, they may not have access to the highest levels of technology and in vitro fertilization in terms of assisted reproductive technology,” Williams said.

“They may be using less high-tech means of assisted reproductive technology, such as clomiphene with insemination, where you stimulate the ovaries to produce more eggs, thereby increasing the number of twins and triplets,” she said. “So we cannot combine assisted reproductive technology with in vitro fertilization. There are less invasive, less high-tech forms of assisted reproductive technology that black mothers and low-income mothers can benefit from.”

Overall, the new data was “very informative,” says Dr. Rachel McConnell, assistant professor of obstetrics and gynecology at the University Vagelos College of Physicians and Surgeons at Columbia Universitywho was not involved in the report, said in an email.

She added that the report’s findings indicated that the American Society of Reproductive Medicine’s guidelines for transferring small numbers of embryos “helped reduce the number of multiple pregnancies” in IVF cycles.