A woman from Texas gives birth to sextuplets on March 15, joining 1 in 4.7 billion other pregnancies to have six babies at once.

Thelma Chiaka from Houston delivered two sets of twin boys and a set of twin girls at the Women's Hospital of Texas. The newborns are receiving treatment at the advanced neonatal intensive care unit. The mother and the babies are in stable conditions.

Rare Multiple Births

The six babies were born in a span of nine minutes from 4:50 a.m. to 4:59 a.m. The hospital did not mention if the birth was natural or through a Caesarean section. The babies' weights ranged from 1 pound and 12 ounces (794 grams) to 2 pounds and 14 ounces at the time of birth (1.3 kilograms).

Multiple births happen when more than one egg cell is released from the ovary and gets fertilized by the sperm or when one fertilized egg splits into two, according to the American College of Obstetricians and Gynecologists (ACOG).

Raising Multiples, an organization dedicated to Mothers of Supertwins communities, said that higher-order pregnancies are not necessarily due to fertility treatments.

"The majority of quintuplet and higher births are not the result of procedures like in-vitro fertilization (IVF) or other assisted reproductive technology (ART), but rather the use of fertility medications: a much lower cost/risk treatment option," Raising Multiples said.

Higher-order births like quintuplets and sextuplets are extraordinary pregnancies. There are fewer than 20 sets of quintuplets and one or fewer sets of sextuplets born in the United States each year.

Preterm birth is the most common complication of multiple pregnancy. ACOG said that babies born earlier than 37 weeks are at risk of breathing problems, learning disabilities, and other short-term and long-term health problems.

Delayed Childbearing Age And Multiple Births

Researchers from Brown University reported that reproductive technology-assisted pregnancies are not the sole cause of multiple births. Women who chose to conceive later in life have higher chances of having multiple babies at once.

"There's a sizable proportion of multiple births that are attributable simply to delaying childbearing. And the percentage of these spontaneous multiples seems to be growing," said author Dr. Eli Adashi, who is also a medical science professor at Brown University's Warren Alpert Medical School.

Analysis of data from CDC ranging from 1949 to 1966 found that white women who conceive at age 35 and above are three times more likely to have fraternal, non-identical twins. African American women have fourfold chances to have twins on the same age.

The probability of carrying higher-order pregnancies such as triplets and quadruplets goes up to 4.5 times and 6.5 times, respectively.

The study was published in the journal Obstetrics & Gynecology.

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