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466 The effect of prematurity on umbilical cord blood gases
374
SPO Abstracts
January 1991
Am J Obstet G, neenl
466 1HE EFFECT OF PREMATIJRITY ON UMBILICAL CORD BLOOD GASES. Diclonson JE', Eriksen NL', Meyer BA', Parisi VM. U1HSC, Houston, TX. Apgar scores are routinely used to assess early neonatal status, but are less predictive in the preterm neonate. Recently, attention has been directed at umbilical cord gases as a method of neonatal evaluation. We hypothesized that there is no significant difference in the umbilical cord blood gas parameters of the preterm infant when compared to the term infant. Using a retrospective chart review of all viable preterm (P) deliveries (>24 weeks and <36 weeks gestation) between January 1986 and December 1989, we constructed a normal curve for the umbilical cord gas parameters of these infants. Lethal major congenital anomalies were excluded from the data base. 1918 infants were eligible for inclusion. Cord arterial blood gas (UABG) values were available for analysis in 76.3% of cases and cord venous gas values in 83.1%. There was no significant difference between these UABG values when compared to those of 1924 term (T) delivenes conducted at our institution between 1986 and 1988.
P
pH 7.25 ± 0.08
191
T
7.24
± 0.07
17.9
Hcm-
p02 ± 7.3
530 ± 10.1
23.8
± 2.3
-3.3
BE ± 29
± 6.9
56.4 ± 8.6
24.1
± 2.2
-3.6
± 27
pCOZ
70.6% of infants were delivered vaginally (V) and 29.4% via Cesarean
(C). There was a significant reduction In the mean arterial pH In group C
compared to V (7.23 ± 008 vs. 7.27 ± 0.07, respectively, p<0.05). The Incidence of newborn depression (5-minute Apgar score <7) in the preterm fetuses was 11 24% and 23.9% of mfants 10 this group were acidemic (arterial pH~7.09). Acidemia was defined statistically as being as ~2SD below the mean pH for our population Analysis of all cephalic presentations revealed that 36.6% of neonates with a 5-minute Apgar score <7 had a normal UABG. We conclude· (1) there is no significant difference in acid-base status at birth in the preterm infant compared to the term mfant, (2) the use of UABG may be of more value than the Apgar score in this subpopulation to assess the immediate neonatal status.
467 CERVICO-VAGINAL ONCOFETAL FIBRONECTIN
IN PRETERM LABOR PATIENTS: A RESULT OF CHORION EXTRACELLULAR MATRIX DEGRADATION. CJ Lockwood, RF Feinberg', H. Kliman', TJ Garite, A. Senyei; Mount Sinai, U Penn & UC Irvine Schools of Medicine: NY, NY, Philadelphia, PA & Irvine CA. Fibronectin bearing a specific oncofetal domain (onfFn) has been isolated from placental extracts and malignant cell lines. The appearance of onfFn in cervico-vaginal mucus from 21 to 37 weeks gestation has recently been shown to strongly correlate with preterm delivery. To account for this observation we characterized the tissue source and structural integrity of onfFn during pregnancy. Immunohistochemical staining demonstrated highly specific localization of onfFn to the extracellular matrix (ECM) of chorionic and placental extravillous trophoblasts. Villi, fetal tissue and decidua all failed to display onfFn. Chorioamnionitis resulted in depletion of onfFn from the chorion consistent with inflammatory-mediated proteolysis. Immunoblot analysis of cervico-vaginal onfFn from clinically uninfected preterm labor patients was consistent with proteolytic degradation, whereas onfFn obtained from amniotic fluid, trophoblast cultures and cervico-vaginal mucus after preterm membrane rupture was not degraded. We conclude: 1) that onfFn Is an extravlllous trophoblast-specific ECM protein produced at sites of decidual-trophoblast contact, and that 2) the presence of cervlco-vaglnal onfFn In patients with preterm labor may result from chorion and/or placental ECM degradation potentially associated with Infection.
468
MAGNESIUM: WHAT LEVEL IS THERAPEUTIC? J.W. Wright,'·' L.E. Ridgway,' D.L. Covington'~ 'Wllmmgton Area Health Education Center, Wilmington, NC 'Umverslty of Texas Health SCience Center at San Antomo Previous studies have suggested that a minimum concentration of magnesium (Mg) is required to achieve myometrial relaxation in vitro. However, a recent clinical study found that no level was associated with su=ssful delay of delivery. We sought to defme a minimum Mg level associated with a reduction in clinical uterine activity. We prospectively evaluated uterine activity using an external tOCOdynamometer before and after MgSO, loading in 50 pre term labor patients. With MgSO, loading, uterine activity declined an average of 9.2 ± 8.2 contractions per hour (paired t-test, p=.OO(1). We then grouped patients 5 separate times by post-loading Mg level «4 vs ~4; <5 vs ~5; <6 vs ~6; <7 vs ~7; <8 vs ~8 mg/dl). We examined 3 outcome variables at each grouping: (1) post-loading contraction frequency, (2) percent change in contraction frequency, (3) su=ss of uterine relaxation (~ 6 contractions per hour). There was no significant difference in any of the 3 outcome variables at any Mg level grouping. Multiple logistic regression with both forward and backward stepping revealed no independent variables (Mg level, change in Mg level, gestational age, multiple gestation, prior Mg exposure, and current betamimetic therapy) predicted su=ss. We conclude that MgSO, does reduce uterine contractions, but a definable minimum therapeutic level for Mg was not found.
469 FREQUENCY OF RECURRENCE OF PRETERM PREMATURE RUPTURE OF MEMBRANES
Am!LI, Lewis DF, Garite n, Major CA, Nageotte MP, Towers CV , Montgomery DM\and Dorchester, W A, Memorial Medical Center of Long Beach and UniverSity of California, Irvme Medical Center, Orange, CA. The reported incidence of pre term premature rupture of membranes (PPROM) ranges between 3 and 18.5%. However, the rate of recurrence of PPROM remains undefined. The current study was undertaken to establIsh the frequency of repeat PPROM in the next pregnancy 10 a high fisk referral practice. Between 1983 and 1987 1050 patients with PPROM were identified at Long Beach Memonal Medical Center (LBMMC). From this had a minimum of 2 consecutive pool of patients, 121 pregnancies under our care, resulting in a total of 255 consecutive pregnanCies for analYSIS. PPROM was defined as rupture of membranes prior to the completion of 36-6/7 weeks. Patients With incompetent cervIx or utenne anomalies were excluded. The average estimated gestatIOnal age (EGA) of PPROM in the index pregnancy was 31.4 ± 4.9 weeks. 39 of the 121 pal1ents had recurrent PPROM in their next pregnancy for a rate of 32.2% (95% CI 23.9-40.5). There was no association between gravity, parity, nor the EGA at the time of PPROM in the index pregnancy and the probability of recurrence.in the next pregnancy. Among the 39 patients with recurrent PPROM the mean EGA III the index pregnancy was 30.9 ± 5.1 weeks versus 33.0 ± 5.1 weeks in the subsequent pregnancy (p=ns). CONCLUSION: We conclude that the frequency of recurrent PPROM in the next pregnancy is 32.2% and that the probability of recurrence is not influenced by the EGA, gravity or parity at the time of PPROM in the index pregnancy.
SPO Abstracts
January 1991
Am J Obstet G, neenl
466 1HE EFFECT OF PREMATIJRITY ON UMBILICAL CORD BLOOD GASES. Diclonson JE', Eriksen NL', Meyer BA', Parisi VM. U1HSC, Houston, TX. Apgar scores are routinely used to assess early neonatal status, but are less predictive in the preterm neonate. Recently, attention has been directed at umbilical cord gases as a method of neonatal evaluation. We hypothesized that there is no significant difference in the umbilical cord blood gas parameters of the preterm infant when compared to the term infant. Using a retrospective chart review of all viable preterm (P) deliveries (>24 weeks and <36 weeks gestation) between January 1986 and December 1989, we constructed a normal curve for the umbilical cord gas parameters of these infants. Lethal major congenital anomalies were excluded from the data base. 1918 infants were eligible for inclusion. Cord arterial blood gas (UABG) values were available for analysis in 76.3% of cases and cord venous gas values in 83.1%. There was no significant difference between these UABG values when compared to those of 1924 term (T) delivenes conducted at our institution between 1986 and 1988.
P
pH 7.25 ± 0.08
191
T
7.24
± 0.07
17.9
Hcm-
p02 ± 7.3
530 ± 10.1
23.8
± 2.3
-3.3
BE ± 29
± 6.9
56.4 ± 8.6
24.1
± 2.2
-3.6
± 27
pCOZ
70.6% of infants were delivered vaginally (V) and 29.4% via Cesarean
(C). There was a significant reduction In the mean arterial pH In group C
compared to V (7.23 ± 008 vs. 7.27 ± 0.07, respectively, p<0.05). The Incidence of newborn depression (5-minute Apgar score <7) in the preterm fetuses was 11 24% and 23.9% of mfants 10 this group were acidemic (arterial pH~7.09). Acidemia was defined statistically as being as ~2SD below the mean pH for our population Analysis of all cephalic presentations revealed that 36.6% of neonates with a 5-minute Apgar score <7 had a normal UABG. We conclude· (1) there is no significant difference in acid-base status at birth in the preterm infant compared to the term mfant, (2) the use of UABG may be of more value than the Apgar score in this subpopulation to assess the immediate neonatal status.
467 CERVICO-VAGINAL ONCOFETAL FIBRONECTIN
IN PRETERM LABOR PATIENTS: A RESULT OF CHORION EXTRACELLULAR MATRIX DEGRADATION. CJ Lockwood, RF Feinberg', H. Kliman', TJ Garite, A. Senyei; Mount Sinai, U Penn & UC Irvine Schools of Medicine: NY, NY, Philadelphia, PA & Irvine CA. Fibronectin bearing a specific oncofetal domain (onfFn) has been isolated from placental extracts and malignant cell lines. The appearance of onfFn in cervico-vaginal mucus from 21 to 37 weeks gestation has recently been shown to strongly correlate with preterm delivery. To account for this observation we characterized the tissue source and structural integrity of onfFn during pregnancy. Immunohistochemical staining demonstrated highly specific localization of onfFn to the extracellular matrix (ECM) of chorionic and placental extravillous trophoblasts. Villi, fetal tissue and decidua all failed to display onfFn. Chorioamnionitis resulted in depletion of onfFn from the chorion consistent with inflammatory-mediated proteolysis. Immunoblot analysis of cervico-vaginal onfFn from clinically uninfected preterm labor patients was consistent with proteolytic degradation, whereas onfFn obtained from amniotic fluid, trophoblast cultures and cervico-vaginal mucus after preterm membrane rupture was not degraded. We conclude: 1) that onfFn Is an extravlllous trophoblast-specific ECM protein produced at sites of decidual-trophoblast contact, and that 2) the presence of cervlco-vaglnal onfFn In patients with preterm labor may result from chorion and/or placental ECM degradation potentially associated with Infection.
468
MAGNESIUM: WHAT LEVEL IS THERAPEUTIC? J.W. Wright,'·' L.E. Ridgway,' D.L. Covington'~ 'Wllmmgton Area Health Education Center, Wilmington, NC 'Umverslty of Texas Health SCience Center at San Antomo Previous studies have suggested that a minimum concentration of magnesium (Mg) is required to achieve myometrial relaxation in vitro. However, a recent clinical study found that no level was associated with su=ssful delay of delivery. We sought to defme a minimum Mg level associated with a reduction in clinical uterine activity. We prospectively evaluated uterine activity using an external tOCOdynamometer before and after MgSO, loading in 50 pre term labor patients. With MgSO, loading, uterine activity declined an average of 9.2 ± 8.2 contractions per hour (paired t-test, p=.OO(1). We then grouped patients 5 separate times by post-loading Mg level «4 vs ~4; <5 vs ~5; <6 vs ~6; <7 vs ~7; <8 vs ~8 mg/dl). We examined 3 outcome variables at each grouping: (1) post-loading contraction frequency, (2) percent change in contraction frequency, (3) su=ss of uterine relaxation (~ 6 contractions per hour). There was no significant difference in any of the 3 outcome variables at any Mg level grouping. Multiple logistic regression with both forward and backward stepping revealed no independent variables (Mg level, change in Mg level, gestational age, multiple gestation, prior Mg exposure, and current betamimetic therapy) predicted su=ss. We conclude that MgSO, does reduce uterine contractions, but a definable minimum therapeutic level for Mg was not found.
469 FREQUENCY OF RECURRENCE OF PRETERM PREMATURE RUPTURE OF MEMBRANES
Am!LI, Lewis DF, Garite n, Major CA, Nageotte MP, Towers CV , Montgomery DM\and Dorchester, W A, Memorial Medical Center of Long Beach and UniverSity of California, Irvme Medical Center, Orange, CA. The reported incidence of pre term premature rupture of membranes (PPROM) ranges between 3 and 18.5%. However, the rate of recurrence of PPROM remains undefined. The current study was undertaken to establIsh the frequency of repeat PPROM in the next pregnancy 10 a high fisk referral practice. Between 1983 and 1987 1050 patients with PPROM were identified at Long Beach Memonal Medical Center (LBMMC). From this had a minimum of 2 consecutive pool of patients, 121 pregnancies under our care, resulting in a total of 255 consecutive pregnanCies for analYSIS. PPROM was defined as rupture of membranes prior to the completion of 36-6/7 weeks. Patients With incompetent cervIx or utenne anomalies were excluded. The average estimated gestatIOnal age (EGA) of PPROM in the index pregnancy was 31.4 ± 4.9 weeks. 39 of the 121 pal1ents had recurrent PPROM in their next pregnancy for a rate of 32.2% (95% CI 23.9-40.5). There was no association between gravity, parity, nor the EGA at the time of PPROM in the index pregnancy and the probability of recurrence.in the next pregnancy. Among the 39 patients with recurrent PPROM the mean EGA III the index pregnancy was 30.9 ± 5.1 weeks versus 33.0 ± 5.1 weeks in the subsequent pregnancy (p=ns). CONCLUSION: We conclude that the frequency of recurrent PPROM in the next pregnancy is 32.2% and that the probability of recurrence is not influenced by the EGA, gravity or parity at the time of PPROM in the index pregnancy.