Elective induction of labor as a risk factor for cesarean delivery among low-risk women at term.

OBJECTIVE: To determine the effects of elective induction on the risk of cesarean delivery in a cohort of women with low-risk term pregnancies and to evaluate the costs of elective induction services within our hospital system. METHODS: Records of 1135 eligible women with low-risk, singleton, vertex pregnancies at 38-41 weeks' gestation who were eligible for vaginal delivery were analyzed retrospectively after elective induction (n = 263) or spontaneous labor (n = 872). Outcome measures included cesarean delivery and direct costs. Variables evaluated were parity, maternal age, estimated gestational age, birth weight, prior cesarean delivery, epidural anesthetic use, and provider category. Analysis was by univariable and multivariable regression modeling. RESULTS: Elective induction placed nulliparas at a twofold higher risk for cesarean delivery (odds ratio 2.4, 95% confidence interval 1.2, 4.9) after adjustment for birth weight, maternal age, and gestational age. We found a significantly increased risk of cesarean delivery with increased birth weight for nulliparas (2-66.7%). Increasing maternal age increased the risk of cesarean delivery in all parity groups (P <.05), but particularly among nulliparas (3-26.3%) (P <.001). Electively induced labors that ended in vaginal delivery cost $273 more and required an average of 4 hours more in the hospital before delivery than did noninduced vaginal deliveries (P <.001). CONCLUSION: Elective induction significantly increased the risk of cesarean delivery for nulliparas, and increased in-hospital predelivery time and costs.

The effects of atrial natriuretic factor and angiotensin II on fetal-placental perfusion pressure in the ex vivo cotyledon model.

OBJECTIVE: Our purpose was to investigate pressure changes induced by angiotensin II on placental vasculature pretreated with atrial natriuretic factor. STUDY DESIGN: A dual-perfused cotyledon model was used. Two cotyledons from each placenta were perfused. One cotyledon was infused with atrial natriuretic factor for 30 minutes while the other received an equal volume of saline solution. Three atrial natriuretic factor concentrations were studied: 50 pg/ml, 150 pg/ml, and 15 ng/ml. Both cotyledons received injections of angiotensin II, at the following doses: 1 x 10(-11.5), 1 x 10(-11), 1 x 10(-10.5), and 1 x 10(-10) mol. RESULTS: Cotyledons subjected to 50 pg/ml and 150 pg/ml concentrations of atrial natriuretic factor did not differ in pressure responses to angiotensin II, compared with the saline-infused cotyledons (p > 0.05). The 15 ng/ml concentration of atrial natriuretic factor, however, decreased the pressor response of angiotensin II (p < 0.034). CONCLUSIONS: Atrial natriuretic factor decreases vasoconstriction caused by angiotensin II. However, this was seen only at a supraphysiologic concentration. No effect was noted at normal fetal concentrations of atrial natriuretic factor.

Multiple sclerosis in pregnancy: a review.

This case history discussed multiple sclerosis that began during pregnancy, in a patient with a history of juvenile rheumatoid arthritis. The etiology, epidemiology, pathophysiology, diagnosis, clinical course, and management of MS are reviewed from the point of view of an obstetrician, with emphasis on the interaction between MS and pregnancy. The similarities and differences between MS and rheumatoid arthritis, with respect to the effect of pregnancy on these diseases, is discussed. Because of the generally beneficial effect of pregnancy on MS and rheumatoid arthritis, and the frequent exacerbations of both diseases seen in the postpartum period, further studies of the relationship between pregnancy and these diseases may provide clues to the immunology and treatment of multiple sclerosis and other autoimmune diseases.

Entry of genital Chlamydia trachomatis into polarized human epithelial cells.

To study the initial invasion process(es) of genital chlamydiae, a model system consisting of hormonally maintained primary cultures of human endometrial gland epithelial cells (HEGEC), grown in a polarized orientation on collagen-coated filters, was utilized. After Chlamydia trachomatis inoculation of the apical surface of polarized HEGEC, chlamydiae were readily visualized, by transmission electron microscopy, in coated pits and coated vesicles. This was true for HEGEC maintained in physiologic concentrations of estrogen (proliferative phase) and of estrogen plus progesterone (secretory phase), despite the finding that association of chlamydiae with secretory-phase HEGEC is significantly reduced (P = 0.025; A.S. Maslow, C.H. Davis, J. Choong, and P.B. Wyrick, Am. J. Obstet. Gynecol. 159:1006-1014, 1988). In contrast, chlamydiae were rarely observed in the clathrin-associated structures if the HEGEC were cultured on plastic surfaces. The same pattern of coated pit versus noncoated pit entry was reproducible in HeLa cells. The quantity of coated pits associated with isolated membrane sheets derived from HeLa cells, grown on poly-L-lysine-coated cover slips in medium containing the female hormones, was not significantly different as monitored by radiolabeling studies and by laser scanning microscopy. These data suggest that culture conditions which mimic in vivo cellular organization may enhance entry into coated pits for some obligate intracellular pathogens.

Estrogen enhances attachment of Chlamydia trachomatis to human endometrial epithelial cells in vitro.

Ultraviolet light-inactivated elementary bodies of Chlamydia trachomatis serovar E were fluorescently tagged with rhodamine isothiocyanate (5 micrograms/ml) and added to primary cultures of human endometrial gland epithelial cells. The elementary bodies, at a multiplicity of infection of 600:1, were allowed to adsorb to the cell monolayers for 1 hour at 35 degrees C in an atmosphere of 5% carbon dioxide. The monolayers were disaggregated by trypsinization and the individual cells were processed in the fluorescent activated cell sorter for chlamydial attachment. This method of analysis revealed attachment of C. trachomatis to approximately 50% of human endometrial gland epithelial cells. Addition of estrogen (10(-10) mol/L) to the culture medium enhanced chlamydial attachment to human endometrial gland epithelial cells to approximately 80% (p less than or equal to 0.005), and progesterone in combination with estrogen reduced chlamydial attachment in a dose-dependent fashion: 1 ng/ml progesterone, approximately 50%; 5 ng/ml, about 30%; 10 ng/ml, about 18%, respectively (p less than or equal to 0.025).

Immunoglobulin levels in fetal anatomic compartments.

Immunoglobulins G, M, and A were found in varying concentrations in four different human fetal anatomic compartments of 17 fetuses in the absence of apparent infection. The highest levels were noted in the thoracic cavity.