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Pregnant women who use cocaine do not have an increased risk of an adverse outcome if their membranes rupture prematurely. In fact, in a study of 528 pregnant women with premature rupture of membranes, those who used cocaine were less likely to have an adverse outcome.

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1067/mob.2001.115745 Byline: Sean C. Blackwell, Mordechai Hallak, Sonia S. Hassan, Stanley M. Berry, Evelyne Russell, Yoram Sorokin Keywords: Magnesium sulfate; ionized magnesium; interleukin-1; interleukin-6; tumor necrosis factor Abstract: Objective: Elevated levels of inflammatory cytokines in the fetus have been linked to neurologic morbidities in preterm neonates. Magnesium sulfate is currently being studied in clinical trials as a potential fetal neuroprotective agent. The purpose of this study was to determine whether intrapartum magnesium sulfate therapy has an effect on the umbilical venous concentrations of interleukin-1[beta], interleukin-6, and tumor necrosis factor-[alpha] at delivery. Study Design: Women with singleton gestations >32 weeks with no clinical indications for magnesium sulfate therapy (preeclampsia or tocolysis) and either clinical chorioamnionitis or prolonged rupture of membranes were recruited for the study. Consenting patients were randomly assigned, in a double-blinded fashion, to receive either magnesium sulfate (6-g load then 2 g/hr) or matched volumes of lactated Ringer's solution until delivery. Fetal blood specimens were obtained by aspiration of the umbilical vein after cord clamping but before placental separation. Umbilical cytokine levels were measured with a sensitive and specific immunoassay. Results: Twenty-two patients were randomly assigned to groups and received either magnesium sulfate (n = 11) or placebo (n = 11). There were no differences in the demographic or clinical characteristics between groups. The umbilical venous ionized magnesium concentration was significantly higher in the magnesium sulfate group (2.32 [+ or -] 0.27 mg/dL vs 1.23 [+ or -] 0.15 mg/dL; P < .001). There were no statistically significant differences between groups with respect to umbilical levels of interleukin-1[beta] (1.5 pg/mL [1.5-58] vs 1.5 pg/mL [1.5-10]; P = .5); interleukin-6 (8.5 pg/mL [1-1000] vs 11.2 pg/mL [1-113]; P = .9); or tumor necrosis factor-[alpha] (16 pg/mL [7.6-20.3] vs 16.6 pg/mL [8.3-22.2]; P = .5). Conclusion: In this pilot study the intrapartum administration of magnesium sulfate does not appear to affect the concentration of inflammatory cytokines in fetal blood at delivery. (Am J Obstet Gynecol 2001;184:1320-4.) Author Affiliation: Detroit, Michigan, and Beer-Sheva, Israel From the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Wayne State University, Detroit.sup.a; and the Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Ben Gurion University/Beer-Sheva..sup.b Article Note: (footnote) [star] Reprint requests: Sean C. Blackwell, MD, Hutzel Hospital, Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, 4707 St Antoine Blvd, Detroit, MI 48201.

The fetal inflammatory response syndrome appears to cause increased blood levels of the receptor for tumor necrosis factor. This syndrome can cause fetal death if it is severe enough. The presence of increased levels of the receptor could block the inflammatory activity of tumor necrosis factor.

Researchers have developed a mathematical model that may predict which pregnant women will develop abruptio placentae. In a review of 170,258 births, 31 risk factors for abruptio placentae were discovered. Abruptio placentae occurs when the placenta detaches from the uterus prematurely.

Placenta growth factor appears to be a normal component of amniotic fluid and decreases in concentration as pregnancy progresses. It does not appear to be involved in premature rupture of membranes or intrauterine infection.

Pregnant women with a shorter than normal cervix have a very high risk of delivering prematurely. This was the conclusion of a study of 6,877 pregnant women who had their cervix measured using ultrasound during the second trimester.

A newborn baby who has a seizure shortly after birth may have developed brain damage two or three days before birth, not during delivery. This was demonstrated in a study of 30 such babies, who had elevated blood levels of nucleated red blood cells. This takes two or three days to happen after blood oxygen levels drop.

The preterm fetus may prepare itself for birth during preterm labor by activating its immune system to fight the infections it may encounter outside the womb. Researchers obtained umbilical cord blood samples from 40 women in preterm labor with unbroken membranes. Four cell surface markers associated with immune system activation were detected in the blood samples, at higher levels than are found in term infants, in infants that were delivered within 72 hours of analysis. Immune system activation did not seem to be affected by steroid treatments, which are given during preterm labor to boost the fetal immune system. Activation of the fetal immune system was not associated with infection before birth.

Pregnancies involving the stuck twin syndrome may be identified by a hemoglobin difference of 5.25 grams per deciliter between the twins. The stuck twin syndrome refers to twin pregnancies where one fetus is much larger than the other, and there is too much fluid in one amniotic sac and not enough in the other. Some hypothesize that the bigger twin receives a larger share of the blood supply than the other twin. Researchers studied eight pairs of twins with the stuck twin syndrome before birth and compared their hemoglobin characteristics to those of twins with and without growth retardation. They found that the amount of hemoglobin difference between twins may grow along with the pregnancy. The smaller fetuses of the stuck twin pairs had much lower levels of all proteins. An abnormal opening in the placental vessels may cause the hemoglobin difference.

Interleukin-1 receptor antagonist (IL-1ra) is normally found in amniotic fluid, and its concentration appears to increase in response to infection in the preterm fetus. IL-1ra blocks the action of interleukin-1, a cytokine involved in the inflammatory process that is capable of causing contractions. Measurements of IL-1ra were made from amniotic fluid samples from 42 women undergoing amniocentesis, blood samples from 39 patients undergoing umbilical cord blood sampling for diagnostic purposes, amniotic fluid from 126 women in preterm labor and 102 women with term pregnancies, and blood samples from 8 nonpregnant women. IL-1ra was found in fetal plasma, amniotic fluid, and maternal blood, and levels rose as pregnancy progressed. Levels increased in fetal plasma and amniotic fluid with preterm infection but not in term pregnancies. Fetal urine is a source of amniotic fluid IL-1ra. Female fetuses had higher levels of IL-1ra than males during the third trimester.

Background: Birth weight (BW/length ratios, ponderal indexes, placental weights, and BW/placental weight ratios have been correlated with perinatal morbidity and mortality. Methods: Cross-sectional survey of live-born, structurally normal, singleton neonates delivered at a tertiary care center in Detroit, Mich, from 1984 through 1991. Subjects were included if dating based on menstrual dates and ultrasonographic estimations agreed with Ballard examination to within 2 weeks. Results: Of 33 138 neonates, 26 983 (81.4%) were black. While all indexes significantly increased with advancing gestational age, only placental weights (without prior draining of blood, blotting the placenta dry, or trimming the membranes or cord) and BW/length ratios significantly increased beyond 40 weeks' gestation. Multivariate analysis of variance revealed that placental weights, BW/placenta ratios, and BW/length ratios were significantly related to gender and ethnicity, but ponderal index was not. Placental weights were larger, and BW/ placenta ratios were smaller than studies that trimmed the placentas before weighing. Conclusions: All indexes were gestational age dependent, but ponderal index and BW/placenta ratios do not increase beyond 40 weeks' gestation. Except for ponderal index, interpretation of these indexes should be specific for ethnicity, gender, and manner of placental preparation. (Arch Pediatr Adolesc Med. 1994;148:508-512), Relationships between the health of newborns and birth weight-length ratios, weight-related indexes, placental weight and birth weight-placenta ratios may provide insight into the causes of perinatal death. Such indexes are specific for the infant's gender, ethnicity and the manner of placental preparation used, however, so no single set of indexes will suffice for all areas. A study of 33,138 newborns in Detroit, Michigan provided a series of indexes based on the above-mentioned measurements. While all indexes increase as gestation progresses, only placental weight and birth weight-length ratios continue to increase significantly after 40 weeks' gestation. Ponderal indexes were found to be unrelated to the baby's weight and gender and ethnicity but the other indexes were found to be significantly related to these factors. Hospitals wishing to use such indexes should be careful to find one that matches their demographics, or develop their own.

Flourescent in situ hybridization chromosome-specific probes allow rapid identification of certain common fetal chromosomal anomalies, but they may not provide complete karyotypes. Therefore, they may miss a substantial percentage of chromosomal defects. In a population at high risk for chromosomal defect, outcomes of 6006 full karyotype determinations were divided into groups that would or would not have been detectable by currently available chromosome-specific probes. Probes could detect trisomies or monosomies of chromosomes 13, 18, 21, X, and Y. Sixty-five percent of the abnormal fetuses would have been detected by chromosome-specific probes. However, the other 35% of abnormal fetuses had other trisomies or chromosomal rearrangements and would have been missed.