Seminars in perinatology
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Premature rupture of the membranes (PROM), defined as rupture of the membranes before the onset of labor, is a common obstetric event occurring in 10% of pregnancies. Most of the time this occurs at or beyond 37 weeks' gestation with only 10% of PROM occurring at less than 37 weeks' gestation. The natural course of PROM is labor, and at term this is associated with a low rate of complications for the mother and the fetus. ⋯ In addition, controversy exists over the gestational age at which expectant management should be abandoned and active interventions to effect delivery pursued. This article discusses the natural history of PROM, the outcome of expectant management in PROM, and maternal and fetal outcomes in these patients. The emphasis of this discussion is on the preterm fetus.
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Seminars in perinatology · Jun 1996
Effect of modulators of hypoxic pulmonary vasoconstriction on the response to inhaled nitric oxide in a neonatal model of severe pulmonary atelectasis.
Hypoxic pulmonary vasoconstriction (HPV) is an intrinsic mechanism that facilitates ventilation to perfusion matching and preservation of oxygenation. We investigated the neonatal HPV response from extensive atelectasis and tested the hypothesis that (I) the resulting hypoxemia is corrected by inhaled nitric oxide (NO); (2) the "pulmonary steal" of blood away from hypoxic area is further improved by modulators of the HPV. Intratracheal injection of steel beads in 32 piglets (7 to 20 days) resulted in atelectasis of 50% to 75% of the lungs. ⋯ Following the development of atelectasis, the peripheral chemoreceptor agonists (ALM and DOX) did not modify gas exchange and had no significant cardiovascular effect. ALM and DOX failed to enhance the response to NO. IND did not alter HPV, but prevented the improvement in gas exchange associated with NO-induced pulmonary vasodilation.
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Seminars in perinatology · Aug 1995
Meta AnalysisHome visits during pregnancy: consequences on pregnancy outcome, use of health services, and women's situations.
This review of eight randomized controlled trials assessed two different types of home visits during pregnancy: (1) those offering social support to high-risk women; and (2) those providing medical care to women with complications. In both categories, pregnancy outcome was not improved when women received home visits. The summary odds ratio for preterm delivery (< 37 weeks) was 1.0 (95% CI: 0.8 to 1.1). ⋯ A better integration of hospital and home services might allow a more rational use of health services for women with complications. In addition, we need to define more precisely the content of home visits providing social support. For this, further research is required on how emotional support, health education, and advice influence the health of women and infants and mother-child interactions.
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Seminars in perinatology · Aug 1995
ReviewCocaine using during pregnancy and low birth weight: the impact of prenatal care and drug treatment.
Cocaine use in pregnancy has been associated with low birth weight. Large population-based studies suggest that 5 to 7% of pregnant women have used cocaine, with much higher rates in low income inner-city women. ⋯ A review of the literature shows that comprehensive care, which includes both prenatal care and drug treatment, seems to be associated with better birth weight outcomes, particularly in women who stop their use in the first trimester. Prenatal care alone, however, is also associated with improved outcomes even if not specialized or linked to drug treatment.
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Seminars in perinatology · Apr 1993
ReviewThe transition from fetal to neonatal circulation: normal responses and implications for infants with heart disease.
The primary function of the circulatory system of both the fetus and newborn is to deliver oxygen to metabolizing organs and return deoxygenated blood to the gas exchange organ to replenish the oxygen and eliminate the waste product CO2. In the fetus, the gas exchange organ is the placenta, and its vascular connections are in a parallel arrangement with the other systemic organs, remote from the pulmonary circulation. In order to supply deoxygenated blood to the placenta and return oxygenated blood to the systemic organs, a series of extracardiac shunts (ductus venosus, ductus arteriosus) and an intracardiac communication (foramen ovale) are necessary. ⋯ Severe right heart obstruction is also well tolerated in the fetus, because the combined fetal cardiac output can be transferred to the aorta, with the ductus arteriosus supplying predominantly lung blood flow. After birth, such "ductal-dependent" pulmonary blood flow can lead to critically low levels of pulmonary blood flow and severe cyanosis with closure of the ductus arteriosus. An understanding of fetal hemodynamics and the acute and chronic changes that occur with transition to the newborn circulation are important for the care of normal newborns and are crucial to the recognition, diagnosis, and management of the newborn with significant congenital heart disease.