Brief Communication © 1991 S. Karger AG, Basel 0006-3126/91/0605-0333S2.75/0
Biol Neonate 1991:60:333-335
Ascorbic Acid Concentration in Amniotic Fluid in Late Pregnancy Bridget Barrett, Elaine Gunter, James Jenkins, Marian Wang Department of Maternal and Child Health, Grady Memorial Hospital, Atlanta, Ga.; Nutritional Biochemistry Laboratory, Center for Disease Control, Atlanta, Ga., and Department of Foods and Nutrition. University of Georgia, Athens. Ga.. USA
Key Words. Ascorbic acid • Smoking • Premature rupture of membrane • Amniotic fluid
Introduction The essentiality of an adequate supply of ascorbic acid (ASA) in maintaining the integrity of the chorioamnion has been demonstrated by in vitro studies [1], Aplin et al. [2] observed a higher incidence of spontaneous premature rupture of the fe tal membrane (PROM) among pregnant women with a serum ASA concentration of less than 0.20 mg/dl. They suggested that a low serum ASA concentration might limit the availability of the vitamin to the fetal membrane (chorioamnion) which could then lead to a decrease in the tensile
strength of the chorioamnion resulting in an increased incidence of PROM. The na ture of this association is, however, ob scure. Smoking reduces the ASA concentration in maternal serum and cord blood in preg nancy [3], In populations with a high rate of tobacco use and poor nutritional status, the incidence of PROM may be increased. The purpose of this study was to investigate the relationship between the ASA concentration in serum and amniotic fluid and the effect of dietary ASA intake and cigarette use on these two parameters in smoking and non smoking pregnant women.
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Abstract. Amniotic fluid and venous blood specimens were obtained from 34 pregnant women and analyzed for the ascorbic acid concentration. The mean amniotic ascorbic acid concentration of smoking pregnant women was less than 50% of that of non-smoking wom en. Pregnant women who smoked had a significantly lower serum and amniotic fluid ascor bic acid concentration than those who did not smoke. No differences were observed between the groups with or without premature rupture of the fetal membrane. The results suggest that ascorbic acid in the amniotic fluid reflects the ascorbic acid status in the blood of pregnant women and smoking had a greater effect in decreasing the ascorbic acid concentration in amniotic fluid than in serum.
334
Subjects and Methods The 11 subjects studied were recruited from those patients admitted to Grady Memorial Hospital with a diagnosis of PROM. Twenty-three control patients were recruited from those patients undergoing elec tive amniocentesis at term for fetal lung maturity studies. Of the 11 subjects in the PROM group. 6 were smokers (54%). and of the 23 in the control group. 4 were smokers ( 17 %). A detailed history was obtained from each subject in order to establish a history of tobacco use, and a dietary history was taken with special attention to the intake of ASA-containing foods. The daily ASA in take and the percentage of recommended daily allow ance (% RDA) were calculated. Amniotic fluid was obtained from each patient, by speculum examination in the PROM patients, and by amniocentesis in the controls. A venous blood speci men was collected at the same time. All samples were collected in the third trimester. Specimens were then analyzed for the ASA content by a modification of the colorimetric method of Roe and Keuther [4], To detect differences between smokers and non-smokers, data were compared using Student's t test.
Barrett/Gunter/Jenkins/Wang
Tabic 1. ASA concentrations of serum and am niotic fluid, their ratios, and dietary ASA intake of PROM (n = II) and control subjects (n = 23)
Serum ASA. pmol/1 PROM group Control group
Mean ± SEM
p
56.78 + 0.398 59.05 + 0.380
0.779
Amniotic fluid ASA. pmol/1 PROM group 127.75 ± 1.290 Control group 158.98 ±1.150
0.676
Ratio: amniotic fluid ASA/serum ASA PROM group 119.23 ± 0.707 Control group 130.59±0.767
0.445
Dietary ASA. intake, mg/day PROM group 87.9 0 ± 55.300 Control group 127.00 + 57.400
0.128
Table 2. ASA concentrations of serum and am niotic fluid, their ratios and dietary ASA intakes of smoking (n = 10) and non-smoking (n = 24) pregnant women Mean ± SEM
P
41.90 ±0.402 64.73 ±0.304
0.003
The medical records indicated that there was little difference in the past obstetrical history between PROM and control subjects. The average age of the study group was 24.4 years and the average age of the control group was 26.4 years. The mean parity for the study group was 2.2 and for the control group 1.9. None of the PROM patients had a previous history of delivery of an infant of less than 2,500 g or PROM at a gestational age of less than 37 weeks. The control group had no record of PROM. The ASA concentration of serum and am niotic fluid is shown in table 1. No statistical differences were found between the PROM and control groups. The mean ASA intake for the PROM group was 87.9 mg/day
Serum ASA. pmol/1 Smokers Non-smokers
Amniotic fluid ASA. pmol/1 Smokers 77.22 ±1.040 Non-smokers 158.58 ±0.970
0.001
Ratio: amniotic fluid/serum Smokers 97.66±0.623 Non-smokers 138.54 + 0.659
0.006
Dietary ASA intake, mg/day Smokers 90.40± 55.800 Non-smokers 117.60 ±57.000
0.223
(109% RDA) as compared to the control group, whose average ASA intake was 120 mg/day (148% RDA). Significant differences were observed in both the serum and amniotic ASA concen-
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Results
Ascorbic Acid Concentration in Amniotic Fluid in Late Pregnancy
Discussion The results of this study offer no support to the observation of Wideman et al. [3] of a relationship between decreased serum ASA and PROM. However, the data show a trend to a lower ASA concentration in both serum and amniotic fluid in the PROM group. Thus an increased number of observations may demonstrate the suggested relation ship. A low serum ASA concentration of smok ers observed in this study agrees well with the data of previous studies [5-7]. The ASA concentrations of amniotic fluid are much higher than the serum concentration. Our study is the first to demonstrate a decreased ASA concentration in the amniotic fluid of the pregnant women who smoke. The mean serum ASA concentration of the smoking pregnant women was about 65% that of the non-smoking pregnant women. The mean amniotic ASA concentration of the smoking pregnant women was less than 50% that of the non-smokers. Of interest was the greatly decreased ratio of amniotic fluid ASA to serum ASA concentration that was observed in smokers as compared to non-smokers. Why smoking pregnant women have such a greater decrease in ASA concentration in the
amniotic fluid than in the serum as com pared to that of the non-smoking pregnant women is not clear. Perhaps smoking in creases fetal utilization of ASA. The results of this study do not substan tiate a significant relationship between PROM and ASA concentrations in the se rum or amniotic fluid. Our findings suggest that amniotic fluid reflects the ASA status in the blood of pregnant women and smoking had a greater effect in decreasing the ASA concentrations in amniotic fluid than in se rum.
References 1 Norkus EP. Hsu H, Cehelsky MR: Effect of ciga rette smoking on the vitamin C status of pregnant women and their offspring. Ann NY Acad Sci 1987:498:580-581. 2 Aplin JD, Campbell S, Donnai P, et al. Impor tance of vitamin C in maintenance of the normal amnion: An experimental study. Placenta I986;7: 377-389. 3 Wideman GL. Baird GH. Bolding OT: Ascorbicacid deficiency and premature rupture of fetal membranes. Am J Obstet Gynecol 1964:88:592— 595. 4 Roe JH. Kuether CA: The determination of ascor bic acid in whole blood and urine through the 2,4dinitrophenylhydrazine derivative of dehydro-as corbic acid. J Biol Chem 1943:147:399-407. 5 Chow CK: Lower levels of vitamin C and caro tenes in plasma of cigarette smokers. J Am Coll Nutr 1986;5:305-312. 6 Keith RE. Mosshalde SB: Ascorbic acid status of smoking and non-smoking adolescent females. Int J Vitam Nutr Res 1986:56:363-366. 7 Hoefel OS: Smoking: An important factor in vita min C deficiency. Int J Vitam Nutr Res 1986; 16 (suppl): 127—137. Dr. Marian Wang Department of Foods and Nutrition University of Georgia Athens, GA 30602 (USA)
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trations between smokers and non-smokers (table 2). The serum ASA concentration was lower in smokers (41.9 pm/1) than in nonsmokers (64.7 pm/l). The concentration of ASA in the amniotic fluid was 77.2 jrm/1 in smokers and 138.9 pm/1 in nonsmokers. The calculated ratio of amniotic ASA concentra tion to serum ASA concentration was signif icantly greater (p < 0.01) in non-smokers (138.54 pm/1) than in smokers (97.7 pm/1).
335
Biol Neonate 1991:60:333-335
Ascorbic Acid Concentration in Amniotic Fluid in Late Pregnancy Bridget Barrett, Elaine Gunter, James Jenkins, Marian Wang Department of Maternal and Child Health, Grady Memorial Hospital, Atlanta, Ga.; Nutritional Biochemistry Laboratory, Center for Disease Control, Atlanta, Ga., and Department of Foods and Nutrition. University of Georgia, Athens. Ga.. USA
Key Words. Ascorbic acid • Smoking • Premature rupture of membrane • Amniotic fluid
Introduction The essentiality of an adequate supply of ascorbic acid (ASA) in maintaining the integrity of the chorioamnion has been demonstrated by in vitro studies [1], Aplin et al. [2] observed a higher incidence of spontaneous premature rupture of the fe tal membrane (PROM) among pregnant women with a serum ASA concentration of less than 0.20 mg/dl. They suggested that a low serum ASA concentration might limit the availability of the vitamin to the fetal membrane (chorioamnion) which could then lead to a decrease in the tensile
strength of the chorioamnion resulting in an increased incidence of PROM. The na ture of this association is, however, ob scure. Smoking reduces the ASA concentration in maternal serum and cord blood in preg nancy [3], In populations with a high rate of tobacco use and poor nutritional status, the incidence of PROM may be increased. The purpose of this study was to investigate the relationship between the ASA concentration in serum and amniotic fluid and the effect of dietary ASA intake and cigarette use on these two parameters in smoking and non smoking pregnant women.
Downloaded by: Nagoya University 133.6.82.173 - 1/11/2019 7:31:31 AM
Abstract. Amniotic fluid and venous blood specimens were obtained from 34 pregnant women and analyzed for the ascorbic acid concentration. The mean amniotic ascorbic acid concentration of smoking pregnant women was less than 50% of that of non-smoking wom en. Pregnant women who smoked had a significantly lower serum and amniotic fluid ascor bic acid concentration than those who did not smoke. No differences were observed between the groups with or without premature rupture of the fetal membrane. The results suggest that ascorbic acid in the amniotic fluid reflects the ascorbic acid status in the blood of pregnant women and smoking had a greater effect in decreasing the ascorbic acid concentration in amniotic fluid than in serum.
334
Subjects and Methods The 11 subjects studied were recruited from those patients admitted to Grady Memorial Hospital with a diagnosis of PROM. Twenty-three control patients were recruited from those patients undergoing elec tive amniocentesis at term for fetal lung maturity studies. Of the 11 subjects in the PROM group. 6 were smokers (54%). and of the 23 in the control group. 4 were smokers ( 17 %). A detailed history was obtained from each subject in order to establish a history of tobacco use, and a dietary history was taken with special attention to the intake of ASA-containing foods. The daily ASA in take and the percentage of recommended daily allow ance (% RDA) were calculated. Amniotic fluid was obtained from each patient, by speculum examination in the PROM patients, and by amniocentesis in the controls. A venous blood speci men was collected at the same time. All samples were collected in the third trimester. Specimens were then analyzed for the ASA content by a modification of the colorimetric method of Roe and Keuther [4], To detect differences between smokers and non-smokers, data were compared using Student's t test.
Barrett/Gunter/Jenkins/Wang
Tabic 1. ASA concentrations of serum and am niotic fluid, their ratios, and dietary ASA intake of PROM (n = II) and control subjects (n = 23)
Serum ASA. pmol/1 PROM group Control group
Mean ± SEM
p
56.78 + 0.398 59.05 + 0.380
0.779
Amniotic fluid ASA. pmol/1 PROM group 127.75 ± 1.290 Control group 158.98 ±1.150
0.676
Ratio: amniotic fluid ASA/serum ASA PROM group 119.23 ± 0.707 Control group 130.59±0.767
0.445
Dietary ASA. intake, mg/day PROM group 87.9 0 ± 55.300 Control group 127.00 + 57.400
0.128
Table 2. ASA concentrations of serum and am niotic fluid, their ratios and dietary ASA intakes of smoking (n = 10) and non-smoking (n = 24) pregnant women Mean ± SEM
P
41.90 ±0.402 64.73 ±0.304
0.003
The medical records indicated that there was little difference in the past obstetrical history between PROM and control subjects. The average age of the study group was 24.4 years and the average age of the control group was 26.4 years. The mean parity for the study group was 2.2 and for the control group 1.9. None of the PROM patients had a previous history of delivery of an infant of less than 2,500 g or PROM at a gestational age of less than 37 weeks. The control group had no record of PROM. The ASA concentration of serum and am niotic fluid is shown in table 1. No statistical differences were found between the PROM and control groups. The mean ASA intake for the PROM group was 87.9 mg/day
Serum ASA. pmol/1 Smokers Non-smokers
Amniotic fluid ASA. pmol/1 Smokers 77.22 ±1.040 Non-smokers 158.58 ±0.970
0.001
Ratio: amniotic fluid/serum Smokers 97.66±0.623 Non-smokers 138.54 + 0.659
0.006
Dietary ASA intake, mg/day Smokers 90.40± 55.800 Non-smokers 117.60 ±57.000
0.223
(109% RDA) as compared to the control group, whose average ASA intake was 120 mg/day (148% RDA). Significant differences were observed in both the serum and amniotic ASA concen-
Downloaded by: Nagoya University 133.6.82.173 - 1/11/2019 7:31:31 AM
Results
Ascorbic Acid Concentration in Amniotic Fluid in Late Pregnancy
Discussion The results of this study offer no support to the observation of Wideman et al. [3] of a relationship between decreased serum ASA and PROM. However, the data show a trend to a lower ASA concentration in both serum and amniotic fluid in the PROM group. Thus an increased number of observations may demonstrate the suggested relation ship. A low serum ASA concentration of smok ers observed in this study agrees well with the data of previous studies [5-7]. The ASA concentrations of amniotic fluid are much higher than the serum concentration. Our study is the first to demonstrate a decreased ASA concentration in the amniotic fluid of the pregnant women who smoke. The mean serum ASA concentration of the smoking pregnant women was about 65% that of the non-smoking pregnant women. The mean amniotic ASA concentration of the smoking pregnant women was less than 50% that of the non-smokers. Of interest was the greatly decreased ratio of amniotic fluid ASA to serum ASA concentration that was observed in smokers as compared to non-smokers. Why smoking pregnant women have such a greater decrease in ASA concentration in the
amniotic fluid than in the serum as com pared to that of the non-smoking pregnant women is not clear. Perhaps smoking in creases fetal utilization of ASA. The results of this study do not substan tiate a significant relationship between PROM and ASA concentrations in the se rum or amniotic fluid. Our findings suggest that amniotic fluid reflects the ASA status in the blood of pregnant women and smoking had a greater effect in decreasing the ASA concentrations in amniotic fluid than in se rum.
References 1 Norkus EP. Hsu H, Cehelsky MR: Effect of ciga rette smoking on the vitamin C status of pregnant women and their offspring. Ann NY Acad Sci 1987:498:580-581. 2 Aplin JD, Campbell S, Donnai P, et al. Impor tance of vitamin C in maintenance of the normal amnion: An experimental study. Placenta I986;7: 377-389. 3 Wideman GL. Baird GH. Bolding OT: Ascorbicacid deficiency and premature rupture of fetal membranes. Am J Obstet Gynecol 1964:88:592— 595. 4 Roe JH. Kuether CA: The determination of ascor bic acid in whole blood and urine through the 2,4dinitrophenylhydrazine derivative of dehydro-as corbic acid. J Biol Chem 1943:147:399-407. 5 Chow CK: Lower levels of vitamin C and caro tenes in plasma of cigarette smokers. J Am Coll Nutr 1986;5:305-312. 6 Keith RE. Mosshalde SB: Ascorbic acid status of smoking and non-smoking adolescent females. Int J Vitam Nutr Res 1986:56:363-366. 7 Hoefel OS: Smoking: An important factor in vita min C deficiency. Int J Vitam Nutr Res 1986; 16 (suppl): 127—137. Dr. Marian Wang Department of Foods and Nutrition University of Georgia Athens, GA 30602 (USA)
Downloaded by: Nagoya University 133.6.82.173 - 1/11/2019 7:31:31 AM
trations between smokers and non-smokers (table 2). The serum ASA concentration was lower in smokers (41.9 pm/1) than in nonsmokers (64.7 pm/l). The concentration of ASA in the amniotic fluid was 77.2 jrm/1 in smokers and 138.9 pm/1 in nonsmokers. The calculated ratio of amniotic ASA concentra tion to serum ASA concentration was signif icantly greater (p < 0.01) in non-smokers (138.54 pm/1) than in smokers (97.7 pm/1).
335
