Biomedical subjects
Y Sorokin
Publications and source records attributed to Y Sorokin.
Correlation between gestational age and fetal activity periods.
Cyclic patterns of active and quiet fetal activity were evaluated in 36 clinically normal gravidas between 27 and 42 weeks of gestation. All infants were subsequently delivered between 37 and 42 weeks of gestation, were clinically normal and of appropriate weight for gestational age. Active-quiet cycles occurred less frequently and were of longer duration with increasing gestational age. Regression analysis of the number of active-quiet cycles with gestational age yielded a correlation coefficient of 0.52 (p less than 0.01). The similarity of fetal active-quiet cycles and active and quiet sleep cycles observed after birth is noted.
Active and quiet periods in the preterm and term fetus.
Heart rate variability and fetal movement were used to classify active and quiet fetal periods. Fetuses at 28 to 30 weeks and at 38 to 40 weeks' gestation were compared. A period of fetal movement with increased variability of heart beat was classified as active and one with the absence of movement and diminished fetal heart beat was classified as quiet. The results demonstrated significant differences both in the number of active-quiet cycles per hour and in the length of the active periods. These findings suggest that analogs of fetal behavioral states may be present before birth and have cyclic patterns, and that the time spent in each fetal period is longer in older fetuses.
A comparison between maternal, tocodynamometric, and real-time ultrasonographic assessments of fetal movement.
Fetal movements were simultaneously studied with maternal perception, tocodynamometry, and real-time ultrasonography. A comparison between these three modalities demonstrated good agreement. The percentage of agreement improved with increasing duration of fetal movements. For fetal movements lasting longer than 3 seconds, the agreement between ultrasonography and tocodynamometry was 95.6%. These findings suggest that tocodynamometry is a sensitive method for studying fetal movements.
Fetal behavioral states and fetal evaluation.
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Brain natriuretic peptide and cyclic guanosine-3',5' monophosphate in pre-eclampsia.
The objective of this study is to determine the possibility that pre-eclampsia, a disease characterized by altered vascular tone, may result in altered levels of fetal BNP and cGMP, and to determine whether pre-eclampsia alters the maternal-fetal relationship of BNP and cGMP. Paired maternal and umbilical venous plasma levels of BNP and cGMP were determined in 13 pre-eclamptic and 9 normotensive primigravidas in the third trimester. Statistical analysis was performed using multivariate analysis of variance, linear regression, and canonical correlation. Overall, levels of cGMP were lower in pre-eclampsia (P < 0.03). Pre-eclampsia was also associated with an altered maternal-fetal relationship for BNP and cGMP (P < 0.008, P < 0.02, respectively). With pre-eclampsia, the maternal:fetal ratio was reduced for BNP and was increased for cGMP. Because of its role as a second messenger for many vasoactive hormones, we hypothesize that fetal cGMP levels may better reflect overall vascular tone than do individual hormones. Altered BNP and cGMP maternal-fetal homeostasis raises the possibility of maternal-fetal coordination of vascular control.
Influence of maternal-fetal medicine subspecialization on the frequency of trial of labor in term pregnancies with breech presentation.
OBJECTIVE: To investigate the role of subspecialization in maternal-fetal medicine (MFM) on the frequency of a trial of labor in term pregnancies with breech presentation. METHODS: We conducted a retrospective study of 332 singleton pregnancies > or =37 weeks with nonfootling breech presentation that delivered over a 6-year period (1994-1998) at a university-based, tertiary care hospital. Patients were divided into two groups based on whether the delivery was attended by an MFM or non-MFM obstetrician-gynecologist. Demographic and clinical data were compared between groups and outcome variables included whether the patient had an attempt at vaginal delivery, cesarean delivery after a labor attempt, or vaginal breech delivery. RESULTS: The frequency of labor attempt (OR 1.4, 95% CI 0.9-2.3), vaginal breech success rate (OR 0.6, 95% CI 0.3-1.5), and overall cesarean rates (OR 0.9, 95% CI 0.5-1.7) were similar between groups. Using discriminant function analysis, only nulliparity (R2 = 1.6%, F = 6.0, P = 0.005) and birthweight (R2 = 2.0% F = 6.4, P = 0.01) were associated with trial of vaginal delivery. CONCLUSIONS: Subspecialization in MFM had no impact on the frequency of trial of labor in the term pregnancy with a breech presentation.
Perinatal cellular ion metabolism: 31P-nuclear magnetic resonance spectroscopic analysis of intracellular free magnesium and pH in maternal and cord blood erythrocytes.
OBJECTIVE: We sought to establish and compare the distribution of intracellular and extracellular magnesium and pH in cord and maternal erythrocytes at the time of delivery. METHODS: We used 31P-nuclear magnetic resonance spectroscopy and a magnesium-specific ion-selective electrode apparatus to evaluate plasma and intracellular red cell content of free magnesium, pH, and ionized calcium in blood obtained from cord and corresponding maternal samples. RESULTS: Cord erythrocyte intracellular free magnesium content (110 +/- 4 mumol/L) and pH (7.02 +/- 0.01) were lower than corresponding maternal intracellular values (140 +/- 9 mumol/L, P < .05; and 7.20 +/- 0.02, P < .0005, respectively). The extracellular cord ionized magnesium concentration in plasma was closely related to the intracellular free magnesium concentration (r = 0.71, P < .005). Extracellular ionized magnesium and calcium were both greater in cord than in maternal samples (P < .05 and P < .0005, respectively). CONCLUSION: These data indicate a differential distribution of extracellular and intracellular magnesium and pH in cord versus maternal blood cells. We hypothesize that these deviations are physiological and may serve to maintain tissue oxygen delivery, while at the same time mediating the changes in vascular tone characteristic of birth.
Adrenomedullin levels in normal and preeclamptic pregnancy at term.
OBJECTIVE: To describe maternal plasma levels of adrenomedullin (AM), a hypotensive and natriuretic peptide, in normal and preeclamptic women at term. STUDY DESIGN: Maternal plasma AM levels were determined in 13 preeclamptic and 15 normotensive primigravidas by radioimmunoassay. Plasma samples were obtained with the patients in the lateral recumbent position before the administration of any medications. RESULTS: Women with preeclampsia had significantly elevated AM levels when compared with normotensive controls (42.3 +/- 10.5 pg/mL versus 16.9 +/- 3.1 pg/mL, P < .011). CONCLUSION: In this pilot study, AM levels were significantly increased at term in preeclamptic women.
Effects of intra-amniotic meconium exposure on the fetal rat: development of a pathogenic model.
OBJECTIVE: To develop an in vivo animal model for the study of the effects of intrauterine meconium exposure on the fetus. METHODS: Timed pregnant Long-Evans rats were purchased on gestational day (GD) 12 and allowed to acclimate for at least 48 h prior to surgery. Laparotomy was performed and both uterine horns were exteriorized through the abdominal incision. A 26-gauge needle was used to inject either 0.1-cm(3) sterile normal saline or a 20% meconium suspension into each individual gestational sac. The uterus was returned to the abdomen and the incision was closed. On GD 21 (term = 21 days) a cesarean section was completed and the number and viability of fetuses in each horn were recorded. RESULTS: A total of 14 animals were involved in this pilot study. One rat underwent sham surgery with only intra-amniotic saline injection and 13/15 fetuses survived to term. Two animals that underwent surgery on day 18 expired < 24 h postinjection. Eleven maternal animals were injected on GD 20 and underwent cesarean delivery at term; survival rates for saline-injected animals were 71.2% compared to 66.2% for meconium-exposed fetuses. CONCLUSION: We have established an in vivo animal model that allows for the examination of the effects of prolonged intrauterine meconium exposure on the fetus.
Meconium staining and meconium aspiration syndrome. Is there seasonal variation?
OBJECTIVE: To determine whether the incidence of pregnancies complicated by meconium-stained amniotic fluid (MSAF) or meconium aspiration syndrome (MAS) differs with seasonal changes. METHODS: An established perinatal database was used to identify all term (> or = 37 weeks) singleton gestations resulting in a live birth from January 1, 1997 to December 31, 1999. Patients were divided into groups based on the season of delivery: winter (December-February), spring (March-May), summer (June-August), and fall (September-November). Rates of MSAF (%MSAF/total deliveries) and MAS (%MAS/total deliveries) were calculated and compared among seasons. Local climatic data (average monthly temperature and monthly precipitation) were obtained from the National Weather Service. Multiple logistic regression analysis was performed to control for the effects of confounding variables and odds ratio (OR) with 95% confidence intervals (CI) were calculated. p < 0.05 was considered significant. RESULTS: Over the 3-year study period there were a total of 14,888 deliveries meeting the criteria. MSAF occurred in 3,206 (21.5%) deliveries and MAS developed in 92 (0.6% of total, 2.9% of MSAF). There were no differences in the rate of MSAF (p = 0.2) or MAS (p = 0.6) between seasons. By logistic regression neither season, temperature, nor precipitation were associated with MSAF or MAS. CONCLUSIONS: Our findings suggest that over the period examined there were no significant seasonal variations in the incidence of MSAF or MAS.
Effects of intrapartum zidovudine therapy on fetal heart rate parameters in women with human immunodeficiency virus infection.
OBJECTIVE: To determine the effects of intrapartum maternal administration of zidovudine on fetal heart rate (FHR) parameters in women infected with the human immunodeficiency virus (HIV). METHODS: Term HIV-infected women who delivered at our institution (1995-1998) were identified by medical records coding. Sixty minutes of FHR tracing prior to zidovudine administration and 60 min of FHR tracing 2 h after initiation of therapy were reviewed by 3 perinatologists blinded to patient status. Data were compared with paired t tests; p < 0.05 was considered significant. Inter- and intra-observer FHR interpretation variation were calculated. RESULTS: Ten patients met study criteria. Their demographic data included: Maternal age 26.5 +/- 6.5 years, gestational age 38.9 +/- 1.3 weeks, median parity 2 (range 0-3). Eighty percent were African American. There were no significant differences in FHR parameters after intravenous zidovudine therapy (pretreatment versus 2 h after treatment) with respect to FHR baseline (p = 0.2), FHR variability (p = 0.3), or the number of accelerations (p = 0.1). There was also no difference in the number of variable (moderate or severe), early, or prolonged decelerations following zidovudine infusion. CONCLUSION: Two hours of continuous intrapartum intravenous infusion of zidovudine does not alter any parameter of the FHR in the laboring HIV-infected gravida.
Comparison of intrapartum fetal monitor tracings of karyotypically abnormal and control infants.
To determine if there are any specific monitoring patterns associated with chromosomal abnormalities the intrapartum tracings of 17 postnatally diagnosed karyotypically abnormal infants were obtained. Controls were randomly selected from infants born on the same day at the same gestational age. The tracings from these two groups were independently evaluated. Comparison of the monitor interpretations showed: (1) the karyotypically abnormal group was more likely to have decreased or absent short- (p < 0.001) and long-term (p < 0.01) variability; (2) accelerations were more likely to be represented in the control group (p < 0.001); (3) no significant differences were found in the baseline heart rates or in the presence or frequency of mild, moderate, or severe variable or late decelerations. These findings may reflect underlying central nervous system abnormalities as opposed to uteroplacental insufficiency, but are not specific to karyotypically abnormal infants.
Indomethacin and fetal ductus arteriosus: complete closure after cessation of prolonged therapeutic course.
Indomethacin is a very effective tocolytic agent. However, concern about its possible constrictive effect on fetal ductus arteriosus has limited the use of this medication in pregnancy. A 29-year-old woman was treated with indomethacin at 27 weeks of gestation for preterm labor and polyhydramnios. She received a dose of 75 mg/day for 5 weeks. At 35 weeks of gestation, she had a cesarean delivery due to fetal distress, and a hydropic baby was delivered. The infant died shortly after. Nonimmune hydrops fetalis and closed ductus arteriosus were the only pathological findings at autopsy. In utero, irreversible, complete closure of the ductus arteriosus is very rare. In the case presented, prolonged use of indomethacin during pregnancy was associated with complete closure of the ductus arteriosus that developed most probably after discontinuation of therapy. This case emphasizes the need for frequent fetal echocardiography examinations during as well as after maternal indomethacin treatment.
Meconium drug screening of stillborn infants: a feasibility study.
OBJECTIVE: Meconium drug testing of liveborn infants is highly sensitive (87%) and specific (100%). Accurate knowledge of drug use in mothers of stillborns would be beneficial. We determined the feasibility of noninvasive meconium drug screening for opiates and cocaine in stillborns. METHODS: Stillborn infants delivered at our hospital had meconium collected using a 4-mm spatula inserted into the anus. Specimens were analyzed using gas chromatography. Charts were reviewed. RESULTS: Of the 30 specimens obtained, 26 were below the optimal amount needed (0.5 g). Regardless, all samples were analyzed and three were positive for cocaine (10%), none for opiates. Two of the 3 positive samples were of 'insufficient quantity'. In one, the presumptive cause of fetal demise was diabetes, with no additional factors suggesting substance abuse. The other fetal loss was due to idiopathic preterm labor at 21.5 weeks, with a positive UDS. CONCLUSION: In this pilot study, inability to obtain an optimal volume of meconium occurred frequently. However, important and unexpected laboratory data were generated even with 'insufficient quantity'. This highlights the need to develop more refined methodologies for this screening tool in stillborn fetuses.
Pregnancies following treatment by GnRH-a (Decapeptyl) and myomectomy in infertile women with uterine leiomyomata.
PURPOSE: Uterine leiomyomata alone are an infrequent cause of infertility. We presumed that--since the smaller the uterine size at the time of myomectomy, the greater the chances of subsequent conception--diminishing the preoperative tumor size in infertile patients with large leiomyomata prior to myomectomy should be beneficial. PROCEDURE: Decapeptyl (D-Trp6-LHRH) depot 3.2 mg was administered for a period of 3-6 months to 23 infertile women. No causes of infertility were found in these patients except for uterine leiomyomata. In 10 of the 23 patients conservative myomectomy was added to Decapeptyl treatment. FINDINGS: Following Decapeptyl treatment an average decrease in uterine volume of 57% (range: 22%-86%) was observed in all patients. In ten of the 23 patients conservative myomectomy was added to Decapeptyl treatment resulting in a further 16% decrease in uterine volume. Uterine regrowth following Decapeptyl and myomectomy was found to be significantly lower (P < 0.01) when compared with cases treated with Decapeptyl alone. Five of the ten patients treated by Decapeptyl and myomectomy achieved successful pregnancies and delivered. Among the women treated with Decapeptyl without myomectomy, only one patient conceived. CONCLUSIONS: From these findings it may be concluded that combined GnRH and myomectomy is the treatment of choice for infertile women with large uterine leiomyomata.