Abstract
Objective: To examine the proportion of iatrogenic births among all preterm births over a 26-year period.
Patients and methods: A registry-based survey of preterm deliveries between 1987 and 2012 analyzed by the onset of labor: spontaneous with intact membranes, preterm premature rupture of membranes (PPROM) or iatrogenic. Stratification into categories by gestation (22 weeks to 27 weeks and 6 days, 28 weeks to 31 weeks and 6 days, 32 weeks to 33 weeks and 6 days, 34 weeks to 36 weeks and 6 days) was performed. Preterm birth rates were analyzed using the Mantel-Haenszel linear-by-linear association χ2-test (P<0.05 significant). Logistic regression was used to account for potential confounders.
Results: Overall preterm birth rate was 5.9% (31328 deliveries) including 2358 (0.4%) before 28 completed weeks, 3388 (0.6%) between 28 weeks and 31 weeks 6 days, 3970 (0.8%) between 32 weeks and 33 weeks and 6 days, and 21611 (4.1%) between 34 weeks and 36 weeks and 6 days There was an increase in overall preterm birth rate (P<0.001). The rate of iatrogenic preterm births and PPROM increased over time (P<0.001 and P<0.014, respectively). Rates of spontaneous preterm birth decreased (P<0.001). After accounting for potential confounders, year of birth remained an independent risk factor for iatrogenic preterm delivery in all four gestational age categories (P<0.001).
Conclusion: The incidence of iatrogenic preterm birth is increasing with a concomitant decrease in the incidence of spontaneous preterm birth. Attempts to analyze, interpret and decrease preterm birth rates should consider spontaneous and iatrogenic preterm births separately.
References
[1] Steer M. The epidemiology of preterm labor. Br J Obstet Gynaecol. 2005;122:1–3.Search in Google Scholar
[2] Goldenberg RL, Culhane JF, Iams JD, Romero R. Epidemiology and causes of preterm birth. Lancet. 2008;371:75–84.10.1016/S0140-6736(08)60074-4Search in Google Scholar
[3] EURO-PERISTAT Project, with SCPE, EUROCAT, EURONEOSTAT. European Perinatal Health Report. 2008. http://www.europeristat.com/. Accessed August 1, 2015.Search in Google Scholar
[4] EURO-PERISTAT Project with SCPE and EUROCAT. European Perinatal Health Report. The health and care for pregnant women and babies in Europe in 2010. http://www.europeristat.com/. Accessed August 1, 2015.Search in Google Scholar
[5] Martin JA, Hamilton BE, Sutton PD, Ventura SJ, Menacker F, Kirmeyer S, et al. Births: Final data for 2006. National vital statistics reports; vol 57 no 7. Hyattsville, MD: National Center for Health Statistics. 2009.Search in Google Scholar
[6] Hamilton BE, Martin JA, Ventura SJ. Births: Preliminary data for 2008. National vital statistics reports; vol 58 no 16. Hyattsville, MD: National Center for Health Statistics. 2010.Search in Google Scholar
[7] Ananth CV, Joseph KS, Oyelese Y, Demissie K, Vintzileos AM. Trends in preterm birth and perinatal mortality among singletons: United States, 1989 through 2000. Obstet Gynecol. 2005;105:1084–91.10.1097/01.AOG.0000158124.96300.c7Search in Google Scholar
[8] Hack M, Fanaroff AA. Outcomes of children of extremely low birthweights and gestational age in the 1990’s. Early Hum Dev. 1999;53:193–218.10.1016/S0378-3782(98)00052-8Search in Google Scholar
[9] Chang HH, Larson J, Blencowe H, Spong CY, Howson CP, Cairns-Smith S, et al. Preventing preterm births: analysis of trends and potential reductions with interventions in 39 countries with very high human development index. Lancet. 2013;381:223–34.10.1016/S0140-6736(12)61856-XSearch in Google Scholar
[10] Iams JD, Romero R, Culhane JF, Goldenberg RL. Primary, secondary, and tertiary interventions to reduce the morbidity and mortality of preterm birth. Lancet. 2008;371:164–75.10.1016/S0140-6736(08)60108-7Search in Google Scholar
[11] Gyetvai K, Hannah ME, Hodnett ED, Ohlsson A. Tocolytics for preterm labor: a systematic review. Obstet Gynecol. 1999;94:869–77.10.1097/00006250-199911001-00043Search in Google Scholar
[12] Da Fonseca EB, Bittar RE, Damião R, Zugaib M. Prematurity prevention: the role of progesterone. Curr Opin Obstet Gynecol. 2009;21:142–7.10.1097/GCO.0b013e3283294770Search in Google Scholar PubMed
[13] Daskalakis GJ. Prematurity prevention: the role of cerclage. Curr Opin Obstet Gynecol. 2009;21:148–52.10.1097/GCO.0b013e3283294785Search in Google Scholar PubMed
[14] Bujold E, Roberge S, Lacasse Y, Bureau M, Audibert F, Marcoux S, et al. Prevention of preeclampsia and intrauterine growth restriction with aspirin started in early pregnancy: a meta-analysis. Obstet Gynecol. 2010;116:402–14.10.1097/AOG.0b013e3181e9322aSearch in Google Scholar PubMed
[15] Ananth CV, Vintzileos AM. Epidemiology of preterm birth and its clinical subtypes. J Matern Fetal Neonatal Med. 2006;19:773–82.10.1080/14767050600965882Search in Google Scholar PubMed
[16] Ananth CV, Vintzileos AM. Maternal-fetal conditions necessitating a medical intervention resulting in preterm birth. Am J Obstet Gynecol. 2006;195:1557–63.10.1016/j.ajog.2006.05.021Search in Google Scholar PubMed
[17] World Health Organization. Born Too Soon: The Global Action Report on Preterm Birth. 2012;1–111.Search in Google Scholar
[18] Dudenhausen JW. Primary prevention of preterm birth. J Perinat Med. 2014;42:431–3.10.1515/jpm-2014-0036Search in Google Scholar PubMed
[19] Romero R, Nicolaides K, Conde-Agudelo A, Tabor A, O’Brien JM, Cetingoz E, et al. Vaginal progesterone in women with an asymptomatic sonographic short cervix in the midtrimester decreases preterm delivery and neonatal morbidity: a systematic review and metaanalysis of individual patient data. Am J Obstet Gynecol. 2012;206:124.e1–19.10.1016/j.ajog.2011.12.003Search in Google Scholar PubMed PubMed Central
[20] Romero R, Yeo L, Miranda J, Hassan SS, Conde-Agudelo A, Chaiworapongsa T. A blueprint for the prevention of preterm birth: vaginal progesterone for women with a short cervix. J Perinat Med. 2013;41:27–44.10.1515/jpm-2012-0272Search in Google Scholar PubMed PubMed Central
[21] Tul N, Lucovnik M, Verdenik I, Druskovic M, Novak Z, Blickstein I. The contribution of twins conceived by assisted reproduction technology to the very preterm birth rate: a population-based study. Eur J Obstet Gynecol Reprod Biol. 2013;171:311–3.10.1016/j.ejogrb.2013.09.040Search in Google Scholar PubMed
[22] Gunby J, Bissonnette F, Librach C, Cowan L. Assisted reproductive technologies (ART) in Canada: 2006 results from the Canadian ART Register. Fertil Steril. 2010;93:2189–201.10.1016/j.fertnstert.2009.03.102Search in Google Scholar PubMed
[23] Pinborg A, Loft A, Nyboe Andersen A. Neonatal outcome in a Danish national cohort of 8602 children born after in vitro fertilization or intracytoplasmic sperm injection: the role of twin pregnancy. Acta Obstet Gynecol Scand. 2004;83:1071–8.10.1111/j.0001-6349.2004.00476.xSearch in Google Scholar PubMed
[24] Reddy UM, Wapner RJ, Rebar RW, Tasca RJ. Infertility, assisted reproductive technology, and adverse pregnancy outcomes: executive summary of a National Institute of Child Health and Human Development Workshop. Obstet Gynecol. 2007;109:967–77.10.1097/01.AOG.0000259316.04136.30Search in Google Scholar PubMed
[25] Blickstein I, Keith LG. Iatrogenic multiple pregnancy. Semin Neonatol. 2002;7:169–76.10.3109/9780203092934-60Search in Google Scholar
[26] Simões T, Queirós A, Correia L, Rocha T, Dias E, Blickstein I. Gestational diabetes mellitus complicating twin pregnancies. J Perinat Med. 2001;39:437–40.10.1515/jpm.2011.048Search in Google Scholar PubMed
[27] Sibai BM, Hauth J, Caritis S, Lindheimer MD, MacPherson C, Klebanoff M, et al. Hypertensive disorders in twin versus singleton gestations. National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units. Am J Obstet Gynecol. 2000;182:938–42.10.1016/S0002-9378(00)70350-4Search in Google Scholar
[28] Coonrod DV, Hickok DE, Zhu K, Easterling TR, Daling JR. Risk factors for preeclampsia in twin pregnancies: a population-based cohort study. Obstet Gynecol. 1995;85:645–50.10.1016/0029-7844(95)00049-WSearch in Google Scholar
[29] Lucovnik M, Tul N, Verdenik I, Novak Z, Blickstein I. Risk factors for preeclampsia in twin pregnancies: a population-based matched case-control study. J Perinat Med. 2012;40: 379–82.10.1515/jpm-2011-0252Search in Google Scholar PubMed
The authors stated that there are no conflicts of interest regarding the publication of this article.
©2016 by De Gruyter
