1. CDC. ART and multiple births. 2016. https://www.cdc.gov/art/key-findings/multiple-births.html.
2. Elflein J. Birth rate for twins in the United States from 1980 to 2018 (per 1,000 live births). 2019.
3. • ACOG. Multifetal gestations: twin, triplet, and higher-order multifetal pregnancies. 2016. https://www.acog.org/clinical/clinical-guidance/practice-bulletin/articles/2016/10/twin-triplet-and-higher-order-multifetal-pregnancies. This practice bulletin is put forth by the American College of Obstetrics and Gynecology and is an important reference to guide management, for all Obstetricians caring for multifetal gestations.
4. Joyce A. Martin MPH. Births: final data for 2018. National Vital Statistics report. 2019;68(13).
5. Pison G. Twinning rates in developed countries: trends and explanations. 2015. https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1728-4457.2015.00088.x.