Editing Preterm birth (section)

==Diagnosis==
===Placental alpha microglobulin-1===
[[Placental alpha microglobulin-1 (PAMG-1)]] has been the subject of several investigations evaluating its ability to predict imminent spontaneous preterm birth in women with signs, symptoms, or complaints suggestive of [[preterm labor]].<ref name="pmid17329514">{{cite journal | vauthors = Lee SE, Park JS, Norwitz ER, Kim KW, Park HS, Jun JK | title = Measurement of placental alpha-microglobulin-1 in cervicovaginal discharge to diagnose rupture of membranes | journal = Obstetrics and Gynecology | volume = 109 | issue = 3 | pages = 634–640 | date = March 2007 | pmid = 17329514 | doi = 10.1097/01.AOG.0000252706.46734.0a | s2cid = 20732037 }}</ref><ref>{{cite journal | vauthors = Lee SM, Lee J, Seong HS, Lee SE, Park JS, Romero R, Yoon BH | title = The clinical significance of a positive Amnisure test in women with term labor with intact membranes | journal = The Journal of Maternal-Fetal & Neonatal Medicine | volume = 22 | issue = 4 | pages = 305–310 | date = April 2009 | pmid = 19350444 | pmc = 2744034 | doi = 10.1080/14767050902801694 }}</ref><ref>{{cite journal |vauthors=Lee SM, Yoon BH, Park CW, Kim SM, Park JW | year = 2011 | title = Intra-amniotic inflammation in patients with a positive Amnisure test in preterm labor and intact membranes | journal = Am J Obstet Gynecol | volume = 204 | issue = 1| page = S209 | doi=10.1016/j.ajog.2010.10.543}}</ref><ref>{{cite journal | vauthors = Lee SM, Romero R, Park JW, Kim SM, Park CW, Korzeniewski SJ, Chaiworapongsa T, Yoon BH | display-authors = 6 | title = The clinical significance of a positive Amnisure test in women with preterm labor and intact membranes | journal = The Journal of Maternal-Fetal & Neonatal Medicine | volume = 25 | issue = 9 | pages = 1690–1698 | date = September 2012 | pmid = 22280400 | pmc = 3422421 | doi = 10.3109/14767058.2012.657279 }}</ref><ref>{{cite journal | vauthors = Sukchaya K, Phupong V | title = A comparative study of positive rate of placental α-microglobulin-1 test in pre-term pregnant women with and without uterine contraction | journal = Journal of Obstetrics and Gynaecology | volume = 33 | issue = 6 | pages = 566–568 | date = August 2013 | pmid = 23919851 | doi = 10.3109/01443615.2013.807786 | s2cid = 20265539 }}</ref><ref>{{cite journal | vauthors = Nikolova T, Bayev O, Nikolova N, Di Renzo GC | title = Evaluation of a novel placental alpha microglobulin-1 (PAMG-1) test to predict spontaneous preterm delivery | journal = Journal of Perinatal Medicine | volume = 42 | issue = 4 | pages = 473–477 | date = July 2014 | pmid = 24334429 | doi = 10.1515/jpm-2013-0234 | s2cid = 6547430 }}</ref> In one investigation comparing this test to [[fetal fibronectin]] testing and cervical length measurement via [[transvaginal ultrasound]], the test for PAMG-1 (commercially known as the PartoSure test) has been reported to be the single best predictor of imminent spontaneous delivery within 7 days of a patient presenting with signs, symptoms, or complaints of preterm labor. Specifically, the PPV, or [[positive predictive value]], of the tests were 76%, 29%, and 30% for PAMG-1, fFN and CL, respectively (P < 0.01).<ref>Nikolova T, Bayev O, Nikolova N, Di Renzo GC. Comparison of a novel test for placental alpha microglobulin-1 with fetal fibronectin and cervical length measurement for the prediction of imminent spontaneous preterm delivery in patients with threatened preterm labor. J Perinat Med. 2015 Jan 6.</ref>

===Fetal fibronectin===
[[Fetal fibronectin]] (fFN) has become an important biomarker—the presence of this glycoprotein in the cervical or vaginal secretions indicates that the border between the chorion and decidua has been disrupted. A positive test indicates an increased risk of preterm birth, and a negative test has a high predictive value.<ref name=Goldenberg2008/> It has been shown that only 1% of women in questionable cases of preterm labor delivered within the next week when the test was negative.<ref>
{{cite journal | vauthors = Lu GC, Goldenberg RL, Cliver SP, Kreaden US, Andrews WW | title = Vaginal fetal fibronectin levels and spontaneous preterm birth in symptomatic women | journal = Obstetrics and Gynecology | volume = 97 | issue = 2 | pages = 225–228 | date = February 2001 | pmid = 11165586 | doi = 10.1016/S0029-7844(00)01130-3 | s2cid = 34818112 }}</ref>

===Ultrasound===
{{Further|Cervical incompetence}}
[[Obstetric ultrasound]] has become useful in the assessment of the [[cervix]] in women at risk for premature delivery. A short cervix preterm is undesirable: A cervical length of less than {{Convert|25|mm|abbr=on}} at or before 24 weeks of [[Gestational age (obstetrics)|gestational age]] is the most common definition of [[cervical incompetence]].<ref>[http://radiopaedia.org/articles/cervical_incompetence Cervical incompetence] {{webarchive|url=https://web.archive.org/web/20140307205141/http://radiopaedia.org/articles/cervical_incompetence |date=7 March 2014 }} from [[Radiopaedia]]. Authors: Dr Praveen Jha and Dr Laughlin Dawes et al. Retrieved Feb 2014</ref>

=== Emerging technologies ===
Technologies under research and development to facilitate earlier diagnosis of preterm births include sanitary pads that identify biomarkers such as fFN and PAMG-1 in vaginal secretions. These devices then calculate a risk of preterm birth and send the findings to a smartphone.<ref>{{Cite web |last= |first= |title=Rea - a smart bandage for pregnant women |url=https://www.innosuisse.ch/inno/en/home/success-stories/projektbeispiele/start-up/rea.html |url-status=dead |archive-url=https://web.archive.org/web/20230905014339/https://www.innosuisse.ch/inno/en/home/success-stories/projektbeispiele/start-up/rea.html |archive-date=2023-09-05 |access-date=2023-09-05 |website=Innosuisse-Swiss Innovation Agency}}</ref> The notion that risk-scoring systems are accurate in predicting preterm birth has been debated in multiple literature reviews.<ref>{{Cite journal |last1=Ferreira |first1=Amaro |last2=Bernardes |first2=João |last3=Gonçalves |first3=Hernâni |date=January 2023 |title=Risk Scoring Systems for Preterm Birth and Their Performance: A Systematic Review |journal=Journal of Clinical Medicine |volume=12 |issue=13 |pages=4360 |doi=10.3390/jcm12134360 |pmid=37445395 |pmc=10342801 |issn=2077-0383 |doi-access=free }}</ref><ref>{{Citation |last1=Davey |first1=Mary-Ann |title=Risk scoring systems for predicting preterm birth with the aim of reducing associated adverse outcomes |date=2010-01-20 |url=http://dx.doi.org/10.1002/14651858.cd004902.pub2 |work=Cochrane Database of Systematic Reviews |access-date=2023-09-05 |place=Chichester, UK |publisher=John Wiley & Sons, Ltd |last2=Watson |first2=Lyndsey |last3=Rayner |first3=Jo Anne |last4=Rowlands |first4=Shelley|editor-first1=Mary-Ann |editor-last1=Davey |doi=10.1002/14651858.cd004902.pub2 |url-access=subscription }}</ref>

===Classification===
[[File:Prenatal development table.svg|center|thumb|800px|Stages in [[prenatal development]], with weeks and months numbered from last menstruation]]
In humans, the usual definition of preterm birth is birth before a [[Gestational age (obstetrics)|gestational age]] of 37 complete weeks.<ref name=Steer2005>
{{cite journal | vauthors = Steer P | title = The epidemiology of preterm labour | journal = BJOG | volume = 112 | issue = Suppl 1 | pages = 1–3 | date = March 2005 | pmid = 15715585 | doi = 10.1111/j.1471-0528.2005.00575.x | s2cid = 33738952 | doi-access = free }}</ref> In the normal human fetus, several organ systems mature between 34 and 37 weeks, and the fetus reaches adequate maturity by the end of this period. One of the main organs greatly affected by premature birth is the lungs. The lungs are one of the last organs to mature in the womb; because of this, many premature babies spend the first days and weeks of their lives on [[ventilator]]s. Therefore, a significant overlap exists between preterm birth and prematurity. Generally, preterm babies are premature and term babies are mature. Preterm babies born near 37 weeks often have no problems relating to prematurity if their lungs have developed adequate [[Pulmonary surfactant|surfactant]], which allows the lungs to remain expanded between breaths. Sequelae of prematurity can be reduced to a small extent by using drugs to accelerate maturation of the fetus, and to a greater extent by preventing preterm birth.