NIH
Twins show slower growth in early pregnancy
A recent NIH study found that twins grow more slowly in early pregnancy than previously thought. The research, published in JAMA Pediatrics, reveals that twins—who are typically smaller at birth compared to singletons—begin their slower growth as early as 15 weeks of gestation. Using 3D ultrasound scans, researchers discovered that twins have significantly less fat tissue and muscle mass than singletons from 15 weeks onward. This contrasts with earlier studies that only documented decreased twin growth in the third trimester.
The study analyzed data from 2,604 singleton pregnancies and 315 twin pregnancies, all of which had individual placentas. The findings suggest that twins' smaller size early in pregnancy may be an adaptation to accommodate the increased resource demands later in pregnancy. If confirmed by further research, these insights could help physicians better monitor and manage twin pregnancies.
Source:
(2025, April 7). NIH. Twins grow more slowly in early pregnancy than previously thought. https://www.nih.gov/news-events/news-releases/twins-grow-more-slowly-early-pregnancy-previously-thought