An official website of the United States government
The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before
sharing sensitive information, make sure you’re on a federal
government site.
The site is secure.
The https:// ensures that you are connecting to the
official website and that any information you provide is encrypted
and transmitted securely.
Szwast A, Rychik J.Szwast A, et al.Clin Perinatol. 2005 Dec;32(4):857-75, viii. doi: 10.1016/j.clp.2005.09.012.Clin Perinatol. 2005.PMID: 16325666Review.
Szwast A, Tian Z, McCann M, Donaghue D, Bebbington M, Johnson M, Wilson RD, Rychik J.Szwast A, et al.Ultrasound Obstet Gynecol. 2007 Jul;30(1):40-6. doi: 10.1002/uog.4032.Ultrasound Obstet Gynecol. 2007.PMID: 17533619Free article.