EI-02908; No of Page 1 Environment International xxx (2015) xxx
Contents lists available at ScienceDirect
Environment International journal homepage: www.elsevier.com/locate/envint
Letter to the editor Interactions of phthalates with preterm birth
To the Editor, The paper by Ferguson and colleagues in the September issue [1] provides an important contribution to the search for etiologies of preterm birth. There are likely multiple pathways to preterm delivery. Risk for spontaneous preterm birth is influenced by race, prior preterm delivery, and cigarette smoking. Additionally, among whites, male fetal gender slightly increases the risk of preterm birth [2,3]. Hour of membrane rupture and labor onset is influenced by chorioamnionitis [4,5]. Both cigarette smoking [6,7] and fetal gender affect sex hormones. It also seems likely that labor induced by chorioamnionitis is less likely to involve sex hormones than other spontaneous labors. Given all this, it seems that examination of the data for both positive and negative interactions between these factors and phthalates might offer some interesting clues in the study of Ferguson et al., or larger future studies.
References [1] Ferguson, K.K., McElrath, T.F., Ko, Y.A., Mukherjee, B., Meeker, J.D., Sep 2014. Variability in urinary phthalate metabolite levels across pregnancy and sensitive windows of exposure for the risk of preterm birth. Environ. Int. 70, 118–124. [2] Cooperstock, M., Campbell, J., Aug 1996. Excess males in preterm birth: interactions with gestational age, race, and multiple birth. Obstet. Gynecol. 88, 189–193. [3] Cooperstock, M.S., Bakewell, J., Herman, A., Schramm, W.F., Sep 1998. Effects of fetal sex and race on risk of very preterm birth in twins. Am. J. Obstet. Gynecol. 179 (3 Pt 1), 762–765. [4] Cooperstock, M., England, J.E., Wolfe, R.A., 1987. Circadian incidence of labor onset hour in preterm birth and chorioamnionitis. Obstet. Gynecol. 70, 853–855. [5] Cooperstock, M., England, J.E., Wolfe, R.A., 1987. Circadian incidence of premature rupture of the membranes in term and preterm births. Obstet. Gynecol 69, 936–941. [6] Shiverick, K., Salafia, C., 1999. Cigarette smoking and pregnancy I: ovarian, uterine and placental effects. Placenta 20, 265–272. [7] Michnovicz, J.J., Herschcop, R.G., Naganuma, H., Bradlow, H.L., Fishman, J., 1986. Increased 2-hydroxylation of estradiol as a possible mechanism for the antiestrogenic effect of cigarette smoking. N. Engl. J. Med. 315, 1305–1310.
Michael Cooperstock Division of Infectious Diseases, Department of Child Health, University of Missouri Health Care, Columbia, MO 65212, United States
4 October 2014 Available online xxxx
http://dx.doi.org/10.1016/j.envint.2014.10.021 0160-4120/© 2014 Elsevier Ltd. All rights reserved.
Please cite this article as: Cooperstock, M., Interactions of phthalates with preterm birth, Environ Int (2015), http://dx.doi.org/10.1016/ j.envint.2014.10.021
Contents lists available at ScienceDirect
Environment International journal homepage: www.elsevier.com/locate/envint
Letter to the editor Interactions of phthalates with preterm birth
To the Editor, The paper by Ferguson and colleagues in the September issue [1] provides an important contribution to the search for etiologies of preterm birth. There are likely multiple pathways to preterm delivery. Risk for spontaneous preterm birth is influenced by race, prior preterm delivery, and cigarette smoking. Additionally, among whites, male fetal gender slightly increases the risk of preterm birth [2,3]. Hour of membrane rupture and labor onset is influenced by chorioamnionitis [4,5]. Both cigarette smoking [6,7] and fetal gender affect sex hormones. It also seems likely that labor induced by chorioamnionitis is less likely to involve sex hormones than other spontaneous labors. Given all this, it seems that examination of the data for both positive and negative interactions between these factors and phthalates might offer some interesting clues in the study of Ferguson et al., or larger future studies.
References [1] Ferguson, K.K., McElrath, T.F., Ko, Y.A., Mukherjee, B., Meeker, J.D., Sep 2014. Variability in urinary phthalate metabolite levels across pregnancy and sensitive windows of exposure for the risk of preterm birth. Environ. Int. 70, 118–124. [2] Cooperstock, M., Campbell, J., Aug 1996. Excess males in preterm birth: interactions with gestational age, race, and multiple birth. Obstet. Gynecol. 88, 189–193. [3] Cooperstock, M.S., Bakewell, J., Herman, A., Schramm, W.F., Sep 1998. Effects of fetal sex and race on risk of very preterm birth in twins. Am. J. Obstet. Gynecol. 179 (3 Pt 1), 762–765. [4] Cooperstock, M., England, J.E., Wolfe, R.A., 1987. Circadian incidence of labor onset hour in preterm birth and chorioamnionitis. Obstet. Gynecol. 70, 853–855. [5] Cooperstock, M., England, J.E., Wolfe, R.A., 1987. Circadian incidence of premature rupture of the membranes in term and preterm births. Obstet. Gynecol 69, 936–941. [6] Shiverick, K., Salafia, C., 1999. Cigarette smoking and pregnancy I: ovarian, uterine and placental effects. Placenta 20, 265–272. [7] Michnovicz, J.J., Herschcop, R.G., Naganuma, H., Bradlow, H.L., Fishman, J., 1986. Increased 2-hydroxylation of estradiol as a possible mechanism for the antiestrogenic effect of cigarette smoking. N. Engl. J. Med. 315, 1305–1310.
Michael Cooperstock Division of Infectious Diseases, Department of Child Health, University of Missouri Health Care, Columbia, MO 65212, United States
4 October 2014 Available online xxxx
http://dx.doi.org/10.1016/j.envint.2014.10.021 0160-4120/© 2014 Elsevier Ltd. All rights reserved.
Please cite this article as: Cooperstock, M., Interactions of phthalates with preterm birth, Environ Int (2015), http://dx.doi.org/10.1016/ j.envint.2014.10.021
