References
- Beck S, Wojdyla D, Say L, Betran AP, Merialdi M, Requejo JH, Rubens C, et al. The worldwide incidence of preterm birth: a systematic review of maternal mortality and morbidity. Bull World Health Organ 2010;88:31–38.
- Moutquin JM. Classification and heterogeneity of preterm birth. BJOG 2003;110 Suppl 20:30–33.
- Astolfi P, Zonta LA. Risks of preterm delivery and association with maternal age, birth order, and fetal gender. Hum Reprod 1999;14:2891–2894.
- Basu R, Malig B, Ostro B. High ambient temperature and the risk of preterm delivery. Am J Epidemiol 2010;172:1108–1117.
- Friger M, Shoham-Vardi I and Abu-Saad K. Trends and seasonality in birth frequency: A comparison of Muslim and Jewish populations in southern Israel: daily time series analysis of 200 009 births, 1988–2005. Hum Reprod 2009;24:1492–1500.
- Team, RDC. R: A language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing; 2011.
- Chen XK, Wen SW, Fleming N, Demissie K, Rhoads GG, Walker M. Teenage pregnancy and adverse birth outcomes: a large population based retrospective cohort study. Int J Epidemiol 2007;36:368–373.
- Hediger ML, Scholl TO, Schall JI, Krueger PM. Young maternal age and preterm labor. Ann Epidemiol 1997;7:400–406.
- Tabcharoen C, Pinjaroen S, Suwanrath C, Krisanapan O. Pregnancy outcome after age 40 and risk of low birth weight. J Obstet Gynaecol 2009;29:378–383.
- McIntyre SH, Newburn-Cook CV, O’Brien B, Demianczuk NN. Effect of older maternal age on the risk of spontaneous preterm labor: a population-based study. Health Care Women Int 2009;30:670–689.
- Darrow LA, Strickland MJ, Klein M, Waller LA, Flanders WD, Correa A, Marcus M, Tolbert PE. Seasonality of birth and implications for temporal studies of preterm birth. Epidemiology 2009;20:699–706.
- Konte JM, Creasy RK, Laros RK Jr. California North Coast Preterm Birth Prevention project. Obstet Gynecol 1988;71:727–730.
- Matsuda S, Kahyo H. Seasonality of preterm births in Japan. Int J Epidemiol 1992;21:91–100.
- Keller CA, Nugent RP. Seasonal patterns in perinatal mortality and preterm delivery. Am J Epidemiol 1983;118:689–698.
- Cooperstock M, Wolfe RA. Seasonality of preterm birth in the Collaborative Perinatal Project: demographic factors. Am J Epidemiol 1986;124:234–241.
- Lee SJ, Steer PJ, Filippi V. Seasonal patterns and preterm birth: a systematic review of the literature and an analysis in a London-based cohort. BJOG 2006;113:1280–1288.
- Lee SJ, Hajat S, Steer PJ, Filippi V. A time-series analysis of any short-term effects of meteorological and air pollution factors on preterm births in London, UK. Environ Res 2008;106:185–194.
- Matsuda S, Kahyo H. Geographic differences in seasonality of preterm births in Japan. Hum Biol 1998;70:919–935.
- Ingemarsson I. Gender aspects of preterm birth. BJOG 2003;110 Suppl 20:34–38.
- Hassold T, Quillen SD, Yamane JA. Sex ratio in spontaneous abortions. Ann Hum Genet 1983;47:39–47.
- Di Renzo GC, Rosati A, Sarti RD, Cruciani L, Cutuli AM. Does fetal sex affect pregnancy outcome? Gend Med 2007;4:19–30.
- Zonta LA, Astolfi P, Ulizzi L. Early selection and sex composition in Italy: a study at the regional level. Hum Biol 1996;68:415–426.
- Winther J. The ontogeny of the pituitary– gonadal axis and sexual differentiation in the human fetus, in Textbook of Fetal Physiology. In: G., Thorburn, editor. New York: Oxford Medical Publications; 1994. p.341.
- Romero R, Scoccia B, Mazor M, Wu YK, Benveniste R. Evidence for a local change in the progesterone/estrogen ratio in human parturition at term. Am J Obstet Gynecol 1988;159:657–660.
- Romero R, Mazor M, Tartakovsky B. Systemic administration of interleukin-1 induces preterm parturition in mice. Am J Obstet Gynecol 1991;165:969–971.
- Bry K, Teramo K, Lappalainen U, Waffarn F, Hallman M. Interleukin-1 receptor antagonist in the fetomaternal compartment. Acta Paediatr 1995;84:233–236.