Preterm delivery

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... 

Bacterial vaginosis is associated with preterm delivery, but treating asymptomatic disease does not appear to decrease this risk.35-37 Consequently, treat only symptomatic disease (Table 44—5). 

Group B Streptococcus bacteriuria should be treated to reduce the rate of preterm delivery. These women should also receive antibiotics at delivery to prevent infection in the newborn. 

Neisseria gonorrhoeae is a risk factor for preterm delivery. Symptoms in the neonate usually start within 2 to 5 days of birth. 

Current recommendations are to administer betamethasone, 12 mg IM every 24 hours for two doses, or dexamethasone, 6 mg IM every 12 hours for four doses, to pregnant women between 26 and 34 weeks gestation who are at risk for preterm delivery within the next 7 days. Benefits from... 

Reproductive effects from lead exposure have been documented in animals and human beings of both sexes. High occupational exposure levels in pregnant women have been associated with increased incidences of spontaneous abortions, miscarriages, and stillbirths. Some studies also seem to indicate that prenatal exposure to lower levels of lead may increase the risk of preterm delivery and reduced birth weight. Lead penetrates the placental barrier and has caused congenital abnormalities in animals. There is no conclusive evidence, however, that low-level lead exposure leads to an increased incidence of... 

Italian Collaborative Groupon Preterm Delivery (ICGPD). (1993). Supplementation and plasma levels of vitamin A premature newborns at risk for chronic lung disease. Dev. Pharmacol. Ther. 20,144—151. 

Birth-weight effect. Caffeinated coffee alone had an adjusted odds ratio of 1.3 (95% confidence limits [CL] = 1.0, 1.7) for preterm delivery mothers who consumed both caffeinated and decaffeinated coffee had an adjusted odds of 2.3 (95% CL = 1.3, 4), whereas those who consumed only decaffeinated coffee showed no increased odds of small-for-gestational age birth, low-birth-weight or preterm delivery. A reduction in mean birth-weight of -3 g per cup per week (95% CL = -5.9, -0.6) for caffeinated coffee and an increase of +0.4 g per cup per week (95% CL = 3.7, 4.5) for decaffeinated coffee was found " h... 

Savitz DA (1994) Paternal exposures and pregnancy outcome miscarriage, stillbirth, low birth weight, preterm delivery. In Olshan AF Mattison DR ed. Male-mediated developmental toxicity. New York, Plenum Press, pp 177-198. 

In an analysis of 595 preterm infants born at 26-32 weeks gestation during a randomized controlled trial for the prevention of lung disease, glucocorticoids given to women at risk of preterm delivery promoted fetal lung maturation, reduced the incidence of respiratory distress syndrome, and reduced neonatal morbidity and mortality (370). Dexamethasone was given as either two doses of 12 mg 24 hours apart or four doses of 6 mg every 6 hours. Mortality was 9.2% after three or more courses, compared with 4.8% after one or two courses. This association was not explained by other factors (maternal or other common preterm morbidities). 

A study in 10 women has been conducted to determine whether betamethasone administered at risk of preterm delivery causes adrenal suppression (375). After adrenal stimulation with corticotropin 1 microgram at 24-25 weeks, each woman received two intramuscular doses of betamethasone 12 mg 24 hours apart 1 week later, another... 

Fisher JE, Smith RS, Lagrandeur R, Lorenz RP. Gestational diabetes mellitus in women receiving beta-adrenergics and corticosteroids for threatened preterm delivery. Obstet Gynecol 1997 90(6) 880-3. 

High-dose lead exposure is a recognized risk factor for stillbirth or spontaneous abortion. Epidemiologic studies of the impact of low-level lead exposure on reproductive outcome such as low birth weight, preterm delivery, or spontaneous abortion have yielded mixed results. However, a well-designed nested case-control study recently detected an odds ratio for spontaneous abortion of 1.8 (95% Cl 1.1-3.1) for every 5 / g/dL increase in maternal blood lead across an approximate range of 5-20 g/dL (Boija-Aburto et al, 1999). In males, blood lead concentrations in excess of 40 / g/dL have been associated with diminished or aberrant sperm production. 

Henriksen TB, Baird DD, Olsen J, Hedegaard M, Secher NJ, Wilcox AJ (1999) Time to pregnancy and preterm delivery. Obstet Gynecol, 89 595-599. 

Cocaine has been associated with both preterm delivery and premature rupture of the membranes (248). Among 85 of 604 expectant mothers with premature rupture of the... 

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