Trends in Multiple Births Conceived Using Assisted Reproductive Technology, United States, 1997–2000

TLDR

The study examined trends in ART‑conceived multiple births in the United States from 1997 to 2000 and estimated their share of all multiple births. Researchers analyzed population‑based data on 109,519 ART‑conceived infants and 15.9 million all births to calculate multiple‑birth rates and the proportion attributable to ART. ART‑conceived multiple births increased, with twin rates rising to 444.7 per 1,000 live births in 2000 and triplet/+ rates falling to 98.7, while ART accounted for 13.6% of all multiple births that year—a rise from 11.2% in 1997 and a share that grew to 92.8% among women aged 45–49.

Abstract

To examine trends in multiple births conceived using assisted reproductive technology (ART) in the United States between 1997 and 2000 and to estimate the proportion of all US multiple births attributable to ART use.We analyzed population-based data of 109 519 live-born infants who were conceived in the United States using ART and born between 1997 and 2000 and population-based data of 15 856 809 live-born infants who were delivered in the United States between 1997 and 2000. Multiple birth rates (the number of live-born infants delivered in multiple gestation pregnancies per 1000 live births) and the proportion of all US multiple births attributable to ART were evaluated.The twin rate for ART patients increased between 1997 and 2000, reaching 444.7 per 1000 live births in 2000, whereas the triplet/+ rate declined substantially from 134.3 to 98.7 per 1000 live births from 1997-2000. From 1997-2000, the proportion of multiple births in the United States attributable to ART increased from 11.2% to 13.6%, whereas the proportion attributable to natural conception decreased from 69.9% to 64.5%. In 2000, the proportion of triplet/+ births attributable to ART and to natural conception was 42.5% and 17.7%, respectively. The contribution of ART to multiple births increased substantially with maternal age, from 11.6% for triplet/+ infants born to women aged 20 to 24 to 92.8% for women aged 45 to 49 years.The contribution of ART to twin birth rates continues to increase, but the contribution of ART to triplet/+ birth rates has declined.