Editing Preterm birth (section)

====Genetics====
There is believed to be a maternal genetic component in preterm birth.<ref name=Kistka2008>
{{cite journal | vauthors = Kistka ZA, DeFranco EA, Ligthart L, Willemsen G, Plunkett J, Muglia LJ, Boomsma DI | title = Heritability of parturition timing: an extended twin design analysis | journal = American Journal of Obstetrics and Gynecology | volume = 199 | issue = 1 | pages = 43.e1–43.e5 | date = July 2008 | pmid = 18295169 | doi = 10.1016/j.ajog.2007.12.014 }}</ref> Estimated heritability of timing-of-birth in women was 34%. However, the occurrence of preterm birth in families does not follow a clear inheritance pattern, thus supporting the idea that preterm birth is a non-Mendelian trait with a polygenic nature.<ref name="Zhang2017">{{cite journal | vauthors = Zhang G, Feenstra B, Bacelis J, Liu X, Muglia LM, Juodakis J, Miller DE, Litterman N, Jiang PP, Russell L, Hinds DA, Hu Y, Weirauch MT, Chen X, Chavan AR, Wagner GP, Pavličev M, Nnamani MC, Maziarz J, Karjalainen MK, Rämet M, Sengpiel V, Geller F, Boyd HA, Palotie A, Momany A, Bedell B, Ryckman KK, Huusko JM, Forney CR, Kottyan LC, Hallman M, Teramo K, Nohr EA, Davey Smith G, Melbye M, Jacobsson B, Muglia LJ | display-authors = 6 | title = Genetic Associations with Gestational Duration and Spontaneous Preterm Birth | journal = The New England Journal of Medicine | volume = 377 | issue = 12 | pages = 1156–1167 | date = September 2017 | pmid = 28877031 | pmc = 5561422 | doi = 10.1056/NEJMoa1612665 }}</ref>