Preterm birth

Preterm birth is defined by the World Health Organisation as birth occurring prior to 37 weeks gestation (normal gestation is 40 weeks) and is the cause of the majority of perinatal morbidity or mortality. By this definition the incidence of preterm birth is 5-10% in the western world [3]. Predicting preterm delivery is extremely difficult, though there are known risk factors that... 

Treat symptomatic trichomoniasis with oral metronidazole in order to alleviate maternal symptoms (Table 44—5). Do not treat asymptomatic disease. There is no evidence suggesting that treatment of asymptomatic disease will reduce the incidence of preterm labor or low birth weight, and systematic review suggests that this practice may even increase the incidence of preterm birth.40... 

A test to determine if the patient has been cured is generally not recommended. However, in patients with recurrent BV, a follow-up after the course of therapy may be warranted. If treatment has been prescribed during pregnancy to reduce preterm birth, perform a repeat exam in 1 month and advise further treatment for recurrent BV. 

For women at high risk for preeclampsia, low-dose aspirin after 12 weeks gestation reduces the risk for preeclampsia by 19%. Aspirin may reduce the risk of preterm birth by 7% and fetal or neonatal death by 16%. Calcium, 1 g/day, is recommended for all pregnant women, as it may help prevent hypertension in pregnant women and reduce the risk of preeclampsia by 31% to 67%. 

Bacterial vaginosis is a risk factor for premature rupture of membranes, preterm labor, preterm birth, spontaneous abortion, and postpartum endometritis. 

Menticoglou SM, Morrison 1, Harman CR, Maiming FA, Lange IR. Maximum possible impact of tocolytics in preventing preterm birth a retrospective assessment. Am J Perinatol 1992 9 394-7. 

ChaUis JR et al. Prostaglandins and mechanisms of preterm birth. Reproduction 2002 81 633-641. 

Cox SM, Sherman M, and Leveno KJ. Randomized investigation of magnesium sulfate for prevention of preterm birth. Am J Obstet Gynecol 1990 163 797-801. 

Ryan MA, Gumbs GR, Conlin AM, Sevick CJ, Jacobson IG, Snell KJ, Spoone T, Smith TC (2008) Evaluation of preterm births and birth defects in liveborn infants of US military women who received smallpox vaccine. Birth Defects Res A Clin Mol Teratol 82 533-539... 

Exposure to environmental chemicals during pregnancy can increase the risk of adverse health ontcomes, inclnding preterm birth, miscarriage, low birth weight, malformations, fimctional... 

Michalek JE, Rahe AJ, Boyle CA. 1998. Paternal dioxin, preterm birth, intrauterine growth retardation, and infant death. Epidemiology 9 161-167. 

Figure 1 also shows the major causes of neonatal deaths (birth to 28 days). The largest fraction of deaths (28%) is attributed to preterm births, which may also result in long-term adverse health consequences (see chapter 4). Thus, the perinatal and neonatal developmental stages can be considered particularly vulnerable periods. 

Ritz B, Yu F, Chapa G, Fruin S (2000) Effect of air pollution on preterm birth among children bom in Southern California between 1989 and 1993. Epidemiology, 11 502-511. 

Preterm birth A birth occurring at 24-37 weeks of pregnancy. 

The use of glutathione as a free radical scavenger in treating oxidative stress improved fetal and neonatal outcome of preterm birth and is described by Buhimschi (3). 

Vermeulen GM, van Zwet AA, Bruinse HW. Changes in the vaginal flora after two percent clindamycin vaginal cream in women at high risk of spontaneous preterm birth. BJOG 2001 108(7) 697-700. 

Women also face some unique health consequences of smoking. For example, women who smoke are at higher risk of cervical cancer, unwanted side effects of using oral contraceptives, and early menopause (Ernster, 1993). Furthermore, smokers who arc pregnant incur a higher risk of spontaneous abortion, preterm births, low-weight babies, and fetal and infant deaths. If the infant is born healthy, there still is risk from nicotine present in the mother s milk (USDHHS, 1987b). 

Infertility rates in both women and men have been continually rising. It is estimated that approximately 50% of human conceptuses fail to reach term. Sperm count concentrations in men have been continually declining over the past 50 years. At the same time, increases in hypspadias, cryp-tochidism, and testicular cancer have further contributed to increasing male infertility. Xenoestrogens have contributed to male infertility as well as to female infertility. Spontaneous abortion rates and preterm births continue to rise, contributing further to infertility. 

Ng SP, Steinetz BG, Lasano SG, Zelikoff JT. Hormonal changes accompanying cigarette smoke-induced preterm births in a mouse model. Exp Biol Med 2006 231(8) 1403 9. 

Torres-Sanchez LE, Berkowitz G, Lopez-CarriUo L. Interuterine lead exposure and preterm birth. 

ACOG Practice Bulletin. Assessment of risk factors for preterm birth. Clinicai management guideUnes for obstetrician-gynecologists. No. 31, October 2001. (Replaces Technical Bulletin No. 206, June 1995 Committee Opinion No. 172, May 1996 Committee Opinion No. 187, September 1997 Committee Opinion No. 198, February 1998 and Committee Opinion No. 251, January 2001). Obstet Gynecol 2001 98 709-16. 

Heine RP> McGregor JA, DuUien VK. Accuracy of salivary estriol testing compared to traditional risk factor assessment in predicting preterm birth. Am J Obstet Gynecol 1999 180 5214-8. 

Heine RP, McGregor JA, Goodwin TM, Artal R, Hayashi RH, Robertson PA, et al. Serial salivary estriol to detect an increased risk of preterm birth. Obstet Gynecol 2000 96 490-7. 

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