- Email: [email protected]
Folate status during pregnancy: relationship with alcohol consumption, other maternal risk factors and pregnancy outcome
19
European Journal of Obstetrics & Gynecology and Reproductic;e Biology, 43 (1992) 19-27
0 1992 Elsevier Science Publishers B.V. All rights reserved 002%2243/92/$05.00 EUROBS 01254
Folate status during pregnancy: relationship with alcohol consumption, other maternal risk factors and pregnancy outcome B. Larroque
‘, M. Kaminski ‘, N. Lelong ‘, M. d’Herbomez and G. C&pin 3
2, P. Dehaene
3, D. Querleu 4
’ INSERM II 149, Wlejuif, ’ Seruice central de Mldecine Nucleaire, Centre Hospitaiier de Lille, 3 Service de Ngonatoiogie, Centre Hospitalier de Roubaiw, and ’ Clinique Uniuersitaire de Gyn~cologie-Obstt!trique et Pathologie de la Reproduction, Pauillon Paul Gellt!, Roubair, France
Accepted for publication 9 July 1991
Summary
This study was designed to identify the factors affecting folate status in pregnant women and to explore the relationship between folate status and alcohol consumption during pregnancy. For this purpose, 347 French women were recruited during 1985-1986 on their first visit to the antenatal clinic at Roubaix Hospital (northern France). Alcohol consumption was ascertained by a standardized interview. Folate status assessment was available for 246 pregnant women who were not given folate supplementation. Average folate levels during pregnancy were lower among young women and smokers. Serum folate values diminished with the educational level, and red cell folate values increased with high parity. Unexpectedly, high red cell folate values were strongly related with high alcohol consumption after adjustment for the maternal risk factors associated with alcohol consumption and folate status. This was probably because in the Roubaix region where the study was conducted women consume mostly beer, which contains folates. Pregnancy outcome was not related to folate levels; birthweight was negatively associated with alcohol consumption during the first trimester of pregnancy. Serum folate; Red cell folate; Pregnancy; Alcohol consumption: Pregnancy outcome
Introduction
During pregnancy, the cell multiplication due to the enlargement of the uterus, placental devel-
Correspondence: D. Querleu, Clinique Universitaire de Gyntcologie-Obstetrique et Pathologie de la Reproduction, Pavillon Paul Gell6, Roubaix, France.
opment and fetal growth increases folate requirements [l]. In addition, when absorption is normal during pregnancy, there is an excess urinary loss of folate [2]. Maternal folate values are significantly correlated with folate intake during pregnancy [31. Folate deficiency, has been incriminated in abortions, birth defects, especially neural tube defects [4], preterm deIivery and low birthweight
20
[5]. It is the second-most important cause of anemia during pregnancy after iron deficiency. The prevalence of folate deficiency depends on the population studied: it is frequent in developing countries, but even in industrial countries some pregnant women were found to have low red cell or serum folate [6]. Some of the maternal risk factors contributing to these low levels have been identified, and include low socioeconomic status, high parity and young age of the mother [5,7]. Alcohol consumption during pregnancy might also modifies the folate status of pregnant women, because alcoholics are frequently deficient in folate. This folate deficiency among alcohol abusers has first been observed by Herbert et al. [8] in 1963; the chief causes are inadequate dietary intake, poor intestinal absorption and reduced liver storage of folate, and the adverse effect of alcohol on folate metabolism [9]. At the same time, many alcoholic patients have low levels of serum folate even when their red cell folate level is not abnormally low. Consequently red cell folate might be a better indicator of tissular folate depletion. Adverse pregnancy outcome due to alcohol consumption during pregnancy and resulting disorders such as Fetal Alcohol Syndrome, as well as certain birth defects due to severe folate deficiency have several features in common. One possible explanation for the low birthweight of children of heavy drinkers might be the effect of alcohol on folate metabolism [lo]. The aim of this study was to examine the relationship between folate status on the one hand, and, on the other, alcohol consumption during pregnancy, maternel risk factors and pregnancy outcome. Population
The population from which participants in the study were selected comprised all the French-born women who attended the antenatal clinic at Roubaix Hospital for their first hospital antenatal visit between May 1985 and January 1986. Of the 782 women who fulfilled these criteria, 698 were interviewed. Women who were drinking three or more glasses of alcoholic beverages per day dur-
ing pregnancy, or whom the hospital suspected to be alcoholics comprised 14% of those interviewed [ll]. A subsample of 347 women was selected for further investigation; in this subsample women with high levels of alcohol consumption were deliberately over-represented. Women were divided into three groups of alcohol consumers: light drinkers (0 to 6 drinks/week), moderate drinkers (7 to 20 drinks/week) and heavy drinkers (21 drinks or more/week). All the heavy drinkers were included in the subsample and for each heavy drinker, one light and one moderate drinker were selected for inclusion. The subsample also included all women suspected to be alcoholics. During the study, the following were excluded from the original subsample of 347 women: 4 women under folate supplementation treatment, 14 who did not return to the Hospital, 5 who gave birth to twins, 2 who had stillbirths, and 9 who stated that they drank no alcohol but were known by the hospital to be alcohol abusers. In the 315 women remaining in the subsample, 245 had blood sample collection for measurement of serum and red cell folates, hemoglobin (Hb), and mean corpuscular volume (MCV). These women were classified according to their alcohol consumption before pregnancy: 82 light drinkers, 75 moderate drinkers and 88 heavy drinkers, and also according to their consumption during the first trimester of pregnancy, as 115 light drinkers, 68 moderate drinkers and 60 heavy drinkers. Investigations
Blood samples were drawn at an average of 33 weeks of gestation (between weeks 14 and 411, and 90% were collected after the 26th week. Plasma and red cell folate concentrations were measured by radioassay L4mersham). Alcohol consumption was evaluated at the first visit to the antenatal clinic by means of a structured questionnaire that included the amount of alcohol consumed according to the type of beverage (wine, beer, cider, aperitifs or liqueurs) during the week, at the weekends, before pregnancy and during the first trimester of pregnancy. Alcohol consumption was calculated as the number of
21
glasses of alcoholic drinks consumed weekly. Each glass was estimated to contain about 10 g of absolute alcohol, whatever the type of drink. Data concerning maternal characteristics including educational level, obstetric history and cigarette consumption, as well as pregnancy outcome, were obtained from the Hospital records. Statistical
analysis
The relationships between folate levels, hemoglobin and MCV were analysed using correlation coefficients and Student’s t-tests. Folate levels and maternal characteristics, including parity, age, educational level, cigarette consumption, height and weight, weight gain during pregnancy, number of antenatal visits, and alcohol consumption, were analysed using correlation coefficients and analysis of variance; beer consumption was also considered, because beer was the most common beverage consumed by our population. As we previously found that alcohol consumption varied with age, parity, educational level and cigarette consumption during pregnancy [l 11, these characteristics were controlled for in the analysis of the relationship between alcohol consumption and folate levels by least-square multiple regression procedures. The relationship of outcome variables and placental weight to folate levels was investigated by least-square multiple regression. The mother’s weight before pregnancy, mother’s height, weight gain during pregnancy, parity, age, educational level, cigarette consumption, and gestational age, were taken into account as confounders; history of previous preterm delivery was also included for gestational age 1121.
TABLE
The number of subjects analysed for each parameter varied because of missing data. Results
Among the 315 women in the sample, folate levels did not vary with the stage of pregnancy at blood collection. Besides, the stage of the pregnancy at blood collection did not differ between the different alcohol groups. With the radioassay used, mean serum folate levels were 2.8 ng/ml (normal > 2.5 ng/ml> and red cell folate levels, 402 ng/ml (normal > 250 ng/ml) as shown in Table I: 53% of the women tested had low serum folate levels, and 7.6% had low red cell folate leveis. Red cell and serum folates values were correlated (r = 0.15, P = 0.01). Serum folate values were closely correlated with MCV (r = 0.19, P = 0.003) and Hb (r = 0.26, P < 0.001). Red cell folate values also positively correlated with MCV (Y = 0.16, P = 0.021, but not with Hb. MCV was high (> 95 prn3) in 15% of the women. An anemia (Hb < 11 g/100 ml) was present in 22%. Of these anemic subjects, 28% had microcytosis (MCV < 85 pm”) and 12%, macrocytosis (MCV > 95%). Anemic women had significantly lower serum folate levels than non-anemic women, and their MCV was also lower. There was no significant difference between the two for red cell folates. Folate lel,els and maternal charateristics
Serum and red cell folates were significantly lower in younger women, and red cell folate was also lower in women with low parity. The more educated the women, the higher their serum folate levels. Red cell folate during pregnancy was
I
Distribution
of biological
Serum folate (ng/ml) Red cell folate (ng/ml) Hemoglobin (g/100 ml) Mean corpuscular (pm3)
parameters
volume
N
m
(s)
Range
Threshold (%I for “abnormal values”
245 238 245 242
2.x 402 11.7 91
(1.6) (126) (10.3) (6.4)
0.6- 10 144 -925 83 -142 36 -107
< 2.5 < 250 < I1 > 95
53 7.6 22 15
TABLE II Folate levels in relation to maternal characteristics Serum folate (ng/ml) N Maternal age < 22 years 23-29 years 2 30 years Parity 0 1 2 3 4 .5 Educational
Red cell folate (ng/ml)
m
(s)
62
2.3
104 79
2.9 3.2
(1.2) (1.6) (1.9)
68 66 49 27 13 22
3.1 2.8 2.8 3.1 2.2 2.6
(1.8) (1.9) (1.3) (1.4) (1.1) (1.5)
129 98 12
2.5 3.0 4.4
0.3) (1.8) (1.8)
170 36 39
2.9 2.9 2.3
(1.7) (1.5) (1.4)
P
0.004
0.44
N
m
(s)
61 100 77
365 400 435
(105) (131) (128)
66 65 48 26 12 21
380 398 379 436 542 419
(105) (127) (119) (124) (180) (118)
125 96 12
410 388 435
(140) (107) (137)
164 36 38
417 365 374
(128) (99) (132)
P
0.005
< 0.001
level
Elementary Technical or secondary University
< 0.001
0.28
Smoking during pregnancy
none 1-9 cigarettes/day
2 10 cigarettes/day
0.08
significantly lower in smokers than non-smokers (Table II). Serum folate levels correlated negatively with the number of cigarettes smoked per
0.02
day (r = -0.13, P = 0.05). The same tendency was noted for red cell folate (r = -0.12, P = 0.06). Folate levels were not related to the other mater-
TABLE III Folate levels in relation to alcohol consumption before and during pregnancy Serum folate (ng/ml) N Number of alcoholics before pregnancy
m
Red cell folate (ng/mgl b)
P
n
m
(s)
P
0.89
48 31 72
371 422 379
(106) (110) (123)
0.01
drinks consumed weekly:
0 l-6 7-20
48 34 75
2.5 3.0 2.8
(1.5) (1.4) (1.5)
21-27 28-34 > 35
21 26 41
3.3 3.0 2.9
(2.3) (1.9) (1.8)
21 26 40
389 438 451
(107) (138) (150)
76 37 64
388 395 395
(111) (115) (124)
13 26 20
404 453 444
(134) (169) (120)
During the first trimester of pregnancy 0 l-6 7-20
78 37 68
2.6 3.3 2.7
(1.6) (1.9) (1.4)
21-27 28-34 > 35
13 26 21
2.6 2.9 2.9
(1.1) (1.2) (1.8)
0.36
0.17
23
nal risk factors studied; i.e. previous preterm delivery, height and weight of mother before pregnancy, weight gain during pregnancy and number of visits to the antenatal clinic. Folate levels and alcohol consumption
Serum folate levels did not differ with alcohol consumption, but red cell folate levels were higher in heavy drinkers than in light or moderate drinkers. This difference was significant before pregnancy and with the same tendency for alcohol consumption of the first trimester (Table III). Consistent results were obtained when looking at correlation coefficients between folate levels and the number of drinks of alcoholic beverages consumed per week: this number was not correlated with serum folate levels but was strongly positively correlated with red cell folate levels for alcohol consumption before pregnancy (I = 0.21, P = 0.001) and in the first trimester of pregnancy (r = 0.16, P = 0.02). Women living in Roubaix when the study was made, chiefly consumed beer. There was also a strong positive correlation between red cell folate levels and the number of glasses of beer consumed weekly before pregnancy (r = 0.18, P =
TABLE
0.006) and during P = 0.015).
The relation between alcohol consumption and folate levels was also adjusted for maternal characteristics related to total alcohol consumption before and during pregnancy, i.e., number of cigarettes smoked daily during pregnancy, and mother’s age, parity and educational level. After adjustment red cell folate levels related significantly with alcohol consumption before pregnancy, and the relation was at the limit of significance for alcohol consumption during the first trimester (Table IV). The negative correlation between the number of cigarettes smoked per day during pregnancy and red cell folate persisted. After adjustment for the above maternal characteristics, serum folate levels did not vary according to alcohol consumption before or during pregnancy. High parity was associated with low serum folate. Folate levels and pregnancy outcome
There was no significant folate levels and pregnancy by neonatal characteristics age, birthweight, crown-heel
to alcohol
consumption
before
and during
pregnancy,
Serum folate
of alcoholic
before pregnancy Maternal age Parity Educational level Number of cigarettes during Number
of alcoholic
pregnancy
and other
maternal
characteristics
(multiple
Red cell folate
P
s (PI
P
P
s(P)
P
0.003 0.11 - 0.23 0.28
0.005 0.024 0.08 0.22
0.54 < 0.001 0.003 0.21
1.3 1.4 7.6 -0.6
0.4 1.9 6.2 18.1
0.003 0.46 0.22 0.97
- 0.019
0.019
0.34
- 4.5
1.5
0.004
0.001 0.10 - 0.20 0.23
0.007 0.02 0.07 0.21
0.88 < 0.001 0.007 0.29
1.1 1.8 7.2 - 7.2
0.6 1.9 6.3 18.3
0.06 0.35 0.25 0.69
- 0.02
0.02
0.39
- 3.9
1.5
0.01
drinks/week
per day
pregnancy
during pregnancy Maternal age Parity Educational level Number of cigarettes during
relationship between outcome, as assessed including gestational length, head circum-
IV
Folate levels in relation regression)
Number
(r = 0.17,
the first trimester
drinks/week
per day
linear
24 TABLE
V
Correlations
between
folate
levels during
Birth weight
Serum folate
0.02 a (245) b
Red cell folate
- 0.02 (238)
pregnancy
and neonatal
Crown heel length
characteristics
Head circumference
0.03
- 0.02
(245) - 0.07
(229)
0.05
0.03
(235)
- 0.05
(245)
(245)
- 0.08
(238)
0.09
0.09
(242)
Placental weight
Agpar score at 5 min
Agpar score at 1 min
0.04
(238)
(238)
(222)
a correlation coefficient b number of subjects
TABLE
VI
Multiple
regression
analysis
of birthweight
and folate
status
Serum folate (ng/ml)
Red cell folate (ng/ml) P
P
s(P)
P
P
Gestational age Mother’s age Parity Educational level (elementary/other) Number of cigarettes/day during pregnancy Mother’s weight Mother’s height Weight gain during pregnancy
150 -0.4 50.1 -6.5 - 15.3 9.3 8.2 19.7
17 6.8 21.6 62.8 5.4 2.7 4.8 5.6
< 0.001 0.95 0.02 0.91 0.005 < 0.001 0.09 < 0.001
149 -0.9 56.2 -22.1 - 15.9 9.4 7.4 20.5
18 6.7 22.1 65.1 5.6 2.7 5.0 5.8
< 0.001 0.89 0.01 0.73 0.005 < 0.001 0.13 < 0.001
Number of alcoholic drinks by week in first trimester of pregnancy Folate
-4.8 3.2
2.0 18
0.016 0.86
-4.5 -0.1
2.0 -0.6
0.02 0.53
ference, Apgar scores at 1 and 5 min and placental weight, either before adjustment for potential confounders (Table V) or after adjusting. Table VI shows the relation between folate levels and birthweight after adjustment. Comparison of women with low levels of serum and red cell folates (< 2.5 and < 250 ng/ml, respectively) with women with normal levels also showed no significant association between folate levels and pregnancy outcome. Birthweight was associated with low alcohol consumption during the first trimester of pregnancy, after adjustment for other maternal risk factors and folate status. Other pregnancy outcome variables were not related to alcohol consumption after such adjustment.
s(P)
Discussion Serum and red cell folate values were positively correlated. Regression analysis showed that red cell folate was significantly related to alcohol consumption before pregnancy, even after adjustment for potential confounders; red cell folate values were negatively related to daily cigarette consumption during pregnancy. Serum folate levels were not related to alcohol consumption either before or during pregnancy. However, serum folate levels were lower for young mothers, and women with high parity. Folate status was not related to any pregnancy outcome variable. After adjustment, birthweight was negatively associated to alcohol consumption during the first trimester of pregnancy.
2s
Twenty-eight percent of women had no blood sample collection. However, the maternal charateristics and pregnancy outcome of these women did not differ from those of the women for whom blood samples were collected. Folate values did not vary according to the stage of pregnancy at blood collection, but most blood samples were collected during the third trimester of pregnancy. Anemia was observed in 22% of the women; this high proportion was due to the generally low socio-economic status of the sample. As the sample was designed to overrepresent the heaviest drinkers, it was not representative of the pregnant women who normally attend the Roubaix hospital antenatal clinics, and the proportion of women of low socioeconomic status was higher than usual. The women with anemia had lower serum folate than non anemic women; as shown in other studies on folate levels and hemoglobin, low folic acid can affect the hemoglobin level 15,131.The positive correlation already mentioned between serum and red cell folates was also found by others [7,14,15,16]. Here, serum folate values seemed low, and red cell folate levels better conserved. The usual threshold for folate deficiency was not applicable to the present results, because the assay method used gave different folates values than those by other methods, especially non-isotopic methods (D’Herbomez, personal communication). However, the augmented requirement for folates at the end of the pregnancy might be reflected by a decrease in serum folate only, without affecting red cell folate [6,14]. Serum folate is an earlier indicator of folic acid deficiency than red cell folate; red cell folate is considered as an indicator of long-term folate status, while serum folate reflects recent dietary intake of folic acid. In this study, serum and red cell folates were positively correlated with MCV, whereas we expected a negative correlation because high folic acid deficiency leads to macrocytosis. However, folate deficiency is often associated with iron deficiency which leads to microcytosis (i.e., a reduction in MCV) and may mask the macrocytosis [7]. Besides, alcohol consumption tended to increase MCV. Here some women may had have iron deficiency, as 22% of them were anemic.
Serum folate was lower in young women and women with high parity. These risk factors have been often been incriminated for folic acid deficiency [17]. A possible explanation is that women with repeated pregnancies do not have time to reconstitute their folate balance and young women have lower folate dietary intake. Cigarette smoking has been little studied in relation to folates during pregnancy; dietary intake of folate is smaller in heavy smokers [18,19]. In our study, socioeconomic status, represented by the educational level, was not significantly related to folate values, after adjustment for alcohol consumption, mother’s age, parity and cigarette consumption. In other studies of folate status and maternal risk factors, adjustment was rarely made [20,21]. Taken together, our findings seem consistent with those reported in the literature for maternal risk factors. In addition, we found a correlation between cigarette consumption and red cell folate. We found no relation between serum folate and alcohol consumption, while red cell folate was positively correlated with the quantity of consumed alcohol. In general, alcohol abusers have low folate levels, due to low dietary folate intake and the effect of alcohol on folate metabolism [22]. However, when beer consumption only was considered, red cell folate rose with the quantity of beer consumed. Wu [23] showed that alcohol abusers who only drank wine or spirits had lower folate levels than those drinking beer, probably because beer contains folic acid and can be an important source of this vitamin for heavy drinkers [8]. In our study, we were not able to distinguish between the effects of different types of beverage, as 80% of alcohol consumed was beer and most of the women drank different types of alcohol beverages. As already stated, the folic acid contained in beer might explain the positive relation we found between red cell folate and alcohol consumption. We had no information about other folate dietary intake. However, there was no correlation between folate levels and indicators of total dietary intake such as prepregnancy maternal weight, or weight gain during pregnancy. To our knowledge, there is no other study of the relationship between alcohol consumption and folate levels during pregnancy.
26
Here, the outcome of pregnancy was not related to folate levels. In animal experiments, ethanol was found to be piacentotoxic and specific folate receptor activity dropped significantly in the ethanol-exposed tissue [24]; it was also shown in beagles that large ethanol consumption and small protein intake could independently of each other depress pup birthweight and maternal red cell folate [25]. Baumslag et al. [26] showed that folate supplementation raised the birthweight of children born to black African women but did not affect the babies of better fed white women living in the same country. Four studies showed that folate supplementation increased birthweight [5,26-281, placental weight [5,27,28] or duration of pregnancy [5]. Two of these studies were conducted in industrial countries [5,27] and two in developing countries 126,281. However, other studies did not show these findings [29-311. Investigations in which groups of women with folate deficiency were compared with a control group showed that birthweight was smaller [33361 or gestation shorter (5,351 in the group with folate deficiency. On the whole, the literature tends to show that folate status does affect the outcome of pregnancy, mostly in populations with a high prevalence of folate deficiency and that folate supplementation is effective in populations who live in developing countries or whose socioeconomic status is low. In conclusion, our study showed that cigarette consumption, which is frequent during pregnancy, was associated with a decrease in red cell folate, although this association requires further confirmation. Beer consumption was associated with enhanced red cell folate. However, this relationship between one particular type of alcohol consumption on folate status must be explored in women consuming other types of beverages. In addition to an apparently positive effect on red cell folate, high alcohol consumption also had negative effects during pregnancy, especially on its outcome, and these effects should not be ignored. Acknowledgements
We thank C. Klein Bertrand who coordinated the study, 0. Klein and D. Subtil for their contri-
bution in data collection, A. Hennion and M. Franczuk for their help in the use of the hospital records, the biology laboratory (A. Bonte), the staff of the Maternity Department, G. Potier de Courcy for her help with the literature, and M. Dreyfus for her confribution in the preparation of the manuscript. The analysis was carried out at the INSERM Computer Center (SC5). The study was partly funded by the ‘Haut ComitC d’Etude et dInformation sur l’Alcoolisme’, contract No. 1984-64. It is part of the CEE Concerted Action on “Maternal alcohol consumption and its effects on pregnancy and child development - EUROMAC”. References 1 Bailey L, Cerda J. Iron and folate nutriture during life cycle. World Rev Nutr Diet 1988;56:56-92. 2 Fleming AF. Urinary excretion of folate in pregnancy. J Obstet Gynaecol Br Commonw 1979;79:916-922. 3 Huber M, Wallins LL, DeRusso P. Folate nutrition in pregnancy. J Am Diet Assoc 1988;7:791-795. 4 Milunsky A, Jick H, Jick S et al. Multivitamin folic acid suplementation in early pregnancy reduced the prevalence of neural tube defects. JAMA 1989;20:28-47. 5 Tchernia G, Blot I, Rey A, Kaltwasser JP, Zittoun J, Papiernik E. Maternal folate status, birthweight and gestational age. Dev Pharmacol Ther 1982;4:58-65. 6 Shojania AM. Folic acid and vitamin B12; deficiency in pregnancy and in the neonatal period. Clin Perinatal 1984;11:433-459. 7 Chanarin I. Folate and cobalamin. Haematology 1985;14: 629-641. 8 Herbert V, Zalusky R, Davidson C. Correlation of folate deficiency with alcoholism and associated macrocytosis, anemia, and liver disease. Ann Int Med 1963;58:977-987. 9 Lambie D, Johnson R. Drugs and folate metabolism. Drugs 1985;30:145-155. 10 Henderson G, Patwardhan R, Hoyumpa A, Schenker S. Foetal alcohol syndrome: overview of pathogenesis. Neurobehav Toxicol Teratol 1981;3:73-80. 11 Kaminski M, Rostand A, Lelong N, Dehaene P, Delestret I, Klein-Bertrand, Querleu D, Crepin G. Consommation d’alcool pendant la grossesse et caracteristiques nbonatales. J Alcool 1989;1:35-46. 12 Kramer MS. Intrauterine growth and gestational duration determinants. Pediatrics 1987;80:502-511. 13 Ek J. Plasma and red cell folate in mothers and infants in normal pregnancies. Acta Obstet Gynecol Stand 1982;61:17-20. 14 EK J. Plasma and red cell folate values in newborn infants and their mothers in relation to gestational age. J Pediatrics 1980;97:288-292.
27
18
19
20
21
22 23
24
25
Hercberg S, Bichon L. Galan P, Christians J, Carroget C, Potier de Courcy G. Iron and folacin status of pregnant women. Relationships with dietary intakes. Nutr Rep Intern 1987;35:915-930. Hoffbrand AV, Newcombe BFA, Mollin DL. Method of assay of red cell folate activity and the value of assay as a test for folate deficiency. J Clin Pathol 1966;19:17-25. King JC. Bronstein MN. Fitch WL, Weiniger J. Nutrient utilization during pregnancy. World Rev Nutr Diet 1987;52:71-142. Rogozinski H, Ankers C, Lennon D, Wild J, Schorah C, Sheppard S, Smithells RW. Folate nutrition in early pregnancy. Hum Nutr: Appl Nutr 1983;37A:357-364. Haste FM, Brooke 0, Anderson M et al. Nutrient intakes during pregnancy: observation on the influence of smoking and social class. Am J Clin Nutr 1990;51:29-36. Ho CH, Yuan CL, Yem SH. Serum folate levels in normal full term pregnant Chinese women. Acta Obstet Gynecol Stand 1988;67:417-20. Herbert V, Colman N, Spivack M, Ocasio E, Ghanta V, Kimmel K, Brenner L, Scott J. Folic acid deficiency in the United States: folate assays in a prenatal clinic. Am J Obstet Gynecol 1979;123:175-179. Hillman R, Steinberg S. The effects of alcohol on folate metabolism. Annu Rev Med 1982;33:345-351. Wu A, Chanarin I, Slavin G, Levi AJ. Folate deficiency in the alcoholic - its relationship to clinical and haematological abnormalities, liver disease and folate stores. Br J Haematol 1975;29:469-478. Fisher SE, Inselman S, Duffy L, Atkensis M, Spencer M, Benedict C. Ethanol and fetal nutrition: effect of chronic ethanol exposure on rat placental growth and membrane associated folic and receptor binding activity. J Pediatr Gastroenterol Nutr. 1985;4:645-649. Schwitzer B, Anderson J, Pick J. Effects of dietary preterm
26
27
28
29 30 31
32
33
34
35
36
and ethanol intake on pregnant beagles fed purified diets. J Nutr 1986;116:689-697. Baumslag N, Edelstein J, Metz J. Reduction of incidence of prematurity by folic acid supplementation in pregnancy. Br Med J 1970;i:lh-17. Rolschau J, Date J, Kristoffersen K. Folic acid supplement and intrauterine growth. Acta Obstet Gynecol Stand 1979;58:343-346. lyengar L, Rajalakshmi K. Effect of folic acid supplements on birthweights of infants. Am J Obstet Gynecol 1975;122:332-336. lyengar L. Folic acid requirements of Indian pregnant women. Am J Ohstet Gynecol 1971;111:13-16. Iyengar L, Apte SV. Prophilaxis of anemia in pregnancy. Am J Clin Nutr 1970;23:725-730. Fletcher J, Gurr A, Fellingham FR. Prankerd AJ, Brant HA, Menzies DN. The value of folic acid supplements in pregnancy. J Obstet Gynaecol Br Emp 1971;78:781-785. Fleming AF, Martin JD, Hahnel R, Westake AJ. Effects of iron and folic acid antenatal supplements on maternal haematology and foetal well being. Med J Austr 1974;2:429-436. Gandy G, Jacobson W. Influence of folic acid on birthweight and growth of the erythroblastotic infant. I Birthweight. Arch Dis Child 1977;52:1-6. Rae PG, Rob PM. Megaloblastic anaemia of pregnancy: a clinical and laboratory study with particular reference to the total and labile serum folate levels. J Clin Pathol 1970;23:379-391. Hunt IF. Murphy NJ, Card BK, Jacob M. Dietary folic acid intake and infant birthweights of pregnant women with low and acceptable red cell folate levels. Fed Proc 1979;38:711-715. Hibbard BM. Folates and the foetus. S Afr Med J 1975:49:1223X1220.
European Journal of Obstetrics & Gynecology and Reproductic;e Biology, 43 (1992) 19-27
0 1992 Elsevier Science Publishers B.V. All rights reserved 002%2243/92/$05.00 EUROBS 01254
Folate status during pregnancy: relationship with alcohol consumption, other maternal risk factors and pregnancy outcome B. Larroque
‘, M. Kaminski ‘, N. Lelong ‘, M. d’Herbomez and G. C&pin 3
2, P. Dehaene
3, D. Querleu 4
’ INSERM II 149, Wlejuif, ’ Seruice central de Mldecine Nucleaire, Centre Hospitaiier de Lille, 3 Service de Ngonatoiogie, Centre Hospitalier de Roubaiw, and ’ Clinique Uniuersitaire de Gyn~cologie-Obstt!trique et Pathologie de la Reproduction, Pauillon Paul Gellt!, Roubair, France
Accepted for publication 9 July 1991
Summary
This study was designed to identify the factors affecting folate status in pregnant women and to explore the relationship between folate status and alcohol consumption during pregnancy. For this purpose, 347 French women were recruited during 1985-1986 on their first visit to the antenatal clinic at Roubaix Hospital (northern France). Alcohol consumption was ascertained by a standardized interview. Folate status assessment was available for 246 pregnant women who were not given folate supplementation. Average folate levels during pregnancy were lower among young women and smokers. Serum folate values diminished with the educational level, and red cell folate values increased with high parity. Unexpectedly, high red cell folate values were strongly related with high alcohol consumption after adjustment for the maternal risk factors associated with alcohol consumption and folate status. This was probably because in the Roubaix region where the study was conducted women consume mostly beer, which contains folates. Pregnancy outcome was not related to folate levels; birthweight was negatively associated with alcohol consumption during the first trimester of pregnancy. Serum folate; Red cell folate; Pregnancy; Alcohol consumption: Pregnancy outcome
Introduction
During pregnancy, the cell multiplication due to the enlargement of the uterus, placental devel-
Correspondence: D. Querleu, Clinique Universitaire de Gyntcologie-Obstetrique et Pathologie de la Reproduction, Pavillon Paul Gell6, Roubaix, France.
opment and fetal growth increases folate requirements [l]. In addition, when absorption is normal during pregnancy, there is an excess urinary loss of folate [2]. Maternal folate values are significantly correlated with folate intake during pregnancy [31. Folate deficiency, has been incriminated in abortions, birth defects, especially neural tube defects [4], preterm deIivery and low birthweight
20
[5]. It is the second-most important cause of anemia during pregnancy after iron deficiency. The prevalence of folate deficiency depends on the population studied: it is frequent in developing countries, but even in industrial countries some pregnant women were found to have low red cell or serum folate [6]. Some of the maternal risk factors contributing to these low levels have been identified, and include low socioeconomic status, high parity and young age of the mother [5,7]. Alcohol consumption during pregnancy might also modifies the folate status of pregnant women, because alcoholics are frequently deficient in folate. This folate deficiency among alcohol abusers has first been observed by Herbert et al. [8] in 1963; the chief causes are inadequate dietary intake, poor intestinal absorption and reduced liver storage of folate, and the adverse effect of alcohol on folate metabolism [9]. At the same time, many alcoholic patients have low levels of serum folate even when their red cell folate level is not abnormally low. Consequently red cell folate might be a better indicator of tissular folate depletion. Adverse pregnancy outcome due to alcohol consumption during pregnancy and resulting disorders such as Fetal Alcohol Syndrome, as well as certain birth defects due to severe folate deficiency have several features in common. One possible explanation for the low birthweight of children of heavy drinkers might be the effect of alcohol on folate metabolism [lo]. The aim of this study was to examine the relationship between folate status on the one hand, and, on the other, alcohol consumption during pregnancy, maternel risk factors and pregnancy outcome. Population
The population from which participants in the study were selected comprised all the French-born women who attended the antenatal clinic at Roubaix Hospital for their first hospital antenatal visit between May 1985 and January 1986. Of the 782 women who fulfilled these criteria, 698 were interviewed. Women who were drinking three or more glasses of alcoholic beverages per day dur-
ing pregnancy, or whom the hospital suspected to be alcoholics comprised 14% of those interviewed [ll]. A subsample of 347 women was selected for further investigation; in this subsample women with high levels of alcohol consumption were deliberately over-represented. Women were divided into three groups of alcohol consumers: light drinkers (0 to 6 drinks/week), moderate drinkers (7 to 20 drinks/week) and heavy drinkers (21 drinks or more/week). All the heavy drinkers were included in the subsample and for each heavy drinker, one light and one moderate drinker were selected for inclusion. The subsample also included all women suspected to be alcoholics. During the study, the following were excluded from the original subsample of 347 women: 4 women under folate supplementation treatment, 14 who did not return to the Hospital, 5 who gave birth to twins, 2 who had stillbirths, and 9 who stated that they drank no alcohol but were known by the hospital to be alcohol abusers. In the 315 women remaining in the subsample, 245 had blood sample collection for measurement of serum and red cell folates, hemoglobin (Hb), and mean corpuscular volume (MCV). These women were classified according to their alcohol consumption before pregnancy: 82 light drinkers, 75 moderate drinkers and 88 heavy drinkers, and also according to their consumption during the first trimester of pregnancy, as 115 light drinkers, 68 moderate drinkers and 60 heavy drinkers. Investigations
Blood samples were drawn at an average of 33 weeks of gestation (between weeks 14 and 411, and 90% were collected after the 26th week. Plasma and red cell folate concentrations were measured by radioassay L4mersham). Alcohol consumption was evaluated at the first visit to the antenatal clinic by means of a structured questionnaire that included the amount of alcohol consumed according to the type of beverage (wine, beer, cider, aperitifs or liqueurs) during the week, at the weekends, before pregnancy and during the first trimester of pregnancy. Alcohol consumption was calculated as the number of
21
glasses of alcoholic drinks consumed weekly. Each glass was estimated to contain about 10 g of absolute alcohol, whatever the type of drink. Data concerning maternal characteristics including educational level, obstetric history and cigarette consumption, as well as pregnancy outcome, were obtained from the Hospital records. Statistical
analysis
The relationships between folate levels, hemoglobin and MCV were analysed using correlation coefficients and Student’s t-tests. Folate levels and maternal characteristics, including parity, age, educational level, cigarette consumption, height and weight, weight gain during pregnancy, number of antenatal visits, and alcohol consumption, were analysed using correlation coefficients and analysis of variance; beer consumption was also considered, because beer was the most common beverage consumed by our population. As we previously found that alcohol consumption varied with age, parity, educational level and cigarette consumption during pregnancy [l 11, these characteristics were controlled for in the analysis of the relationship between alcohol consumption and folate levels by least-square multiple regression procedures. The relationship of outcome variables and placental weight to folate levels was investigated by least-square multiple regression. The mother’s weight before pregnancy, mother’s height, weight gain during pregnancy, parity, age, educational level, cigarette consumption, and gestational age, were taken into account as confounders; history of previous preterm delivery was also included for gestational age 1121.
TABLE
The number of subjects analysed for each parameter varied because of missing data. Results
Among the 315 women in the sample, folate levels did not vary with the stage of pregnancy at blood collection. Besides, the stage of the pregnancy at blood collection did not differ between the different alcohol groups. With the radioassay used, mean serum folate levels were 2.8 ng/ml (normal > 2.5 ng/ml> and red cell folate levels, 402 ng/ml (normal > 250 ng/ml) as shown in Table I: 53% of the women tested had low serum folate levels, and 7.6% had low red cell folate leveis. Red cell and serum folates values were correlated (r = 0.15, P = 0.01). Serum folate values were closely correlated with MCV (r = 0.19, P = 0.003) and Hb (r = 0.26, P < 0.001). Red cell folate values also positively correlated with MCV (Y = 0.16, P = 0.021, but not with Hb. MCV was high (> 95 prn3) in 15% of the women. An anemia (Hb < 11 g/100 ml) was present in 22%. Of these anemic subjects, 28% had microcytosis (MCV < 85 pm”) and 12%, macrocytosis (MCV > 95%). Anemic women had significantly lower serum folate levels than non-anemic women, and their MCV was also lower. There was no significant difference between the two for red cell folates. Folate lel,els and maternal charateristics
Serum and red cell folates were significantly lower in younger women, and red cell folate was also lower in women with low parity. The more educated the women, the higher their serum folate levels. Red cell folate during pregnancy was
I
Distribution
of biological
Serum folate (ng/ml) Red cell folate (ng/ml) Hemoglobin (g/100 ml) Mean corpuscular (pm3)
parameters
volume
N
m
(s)
Range
Threshold (%I for “abnormal values”
245 238 245 242
2.x 402 11.7 91
(1.6) (126) (10.3) (6.4)
0.6- 10 144 -925 83 -142 36 -107
< 2.5 < 250 < I1 > 95
53 7.6 22 15
TABLE II Folate levels in relation to maternal characteristics Serum folate (ng/ml) N Maternal age < 22 years 23-29 years 2 30 years Parity 0 1 2 3 4 .5 Educational
Red cell folate (ng/ml)
m
(s)
62
2.3
104 79
2.9 3.2
(1.2) (1.6) (1.9)
68 66 49 27 13 22
3.1 2.8 2.8 3.1 2.2 2.6
(1.8) (1.9) (1.3) (1.4) (1.1) (1.5)
129 98 12
2.5 3.0 4.4
0.3) (1.8) (1.8)
170 36 39
2.9 2.9 2.3
(1.7) (1.5) (1.4)
P
0.004
0.44
N
m
(s)
61 100 77
365 400 435
(105) (131) (128)
66 65 48 26 12 21
380 398 379 436 542 419
(105) (127) (119) (124) (180) (118)
125 96 12
410 388 435
(140) (107) (137)
164 36 38
417 365 374
(128) (99) (132)
P
0.005
< 0.001
level
Elementary Technical or secondary University
< 0.001
0.28
Smoking during pregnancy
none 1-9 cigarettes/day
2 10 cigarettes/day
0.08
significantly lower in smokers than non-smokers (Table II). Serum folate levels correlated negatively with the number of cigarettes smoked per
0.02
day (r = -0.13, P = 0.05). The same tendency was noted for red cell folate (r = -0.12, P = 0.06). Folate levels were not related to the other mater-
TABLE III Folate levels in relation to alcohol consumption before and during pregnancy Serum folate (ng/ml) N Number of alcoholics before pregnancy
m
Red cell folate (ng/mgl b)
P
n
m
(s)
P
0.89
48 31 72
371 422 379
(106) (110) (123)
0.01
drinks consumed weekly:
0 l-6 7-20
48 34 75
2.5 3.0 2.8
(1.5) (1.4) (1.5)
21-27 28-34 > 35
21 26 41
3.3 3.0 2.9
(2.3) (1.9) (1.8)
21 26 40
389 438 451
(107) (138) (150)
76 37 64
388 395 395
(111) (115) (124)
13 26 20
404 453 444
(134) (169) (120)
During the first trimester of pregnancy 0 l-6 7-20
78 37 68
2.6 3.3 2.7
(1.6) (1.9) (1.4)
21-27 28-34 > 35
13 26 21
2.6 2.9 2.9
(1.1) (1.2) (1.8)
0.36
0.17
23
nal risk factors studied; i.e. previous preterm delivery, height and weight of mother before pregnancy, weight gain during pregnancy and number of visits to the antenatal clinic. Folate levels and alcohol consumption
Serum folate levels did not differ with alcohol consumption, but red cell folate levels were higher in heavy drinkers than in light or moderate drinkers. This difference was significant before pregnancy and with the same tendency for alcohol consumption of the first trimester (Table III). Consistent results were obtained when looking at correlation coefficients between folate levels and the number of drinks of alcoholic beverages consumed per week: this number was not correlated with serum folate levels but was strongly positively correlated with red cell folate levels for alcohol consumption before pregnancy (I = 0.21, P = 0.001) and in the first trimester of pregnancy (r = 0.16, P = 0.02). Women living in Roubaix when the study was made, chiefly consumed beer. There was also a strong positive correlation between red cell folate levels and the number of glasses of beer consumed weekly before pregnancy (r = 0.18, P =
TABLE
0.006) and during P = 0.015).
The relation between alcohol consumption and folate levels was also adjusted for maternal characteristics related to total alcohol consumption before and during pregnancy, i.e., number of cigarettes smoked daily during pregnancy, and mother’s age, parity and educational level. After adjustment red cell folate levels related significantly with alcohol consumption before pregnancy, and the relation was at the limit of significance for alcohol consumption during the first trimester (Table IV). The negative correlation between the number of cigarettes smoked per day during pregnancy and red cell folate persisted. After adjustment for the above maternal characteristics, serum folate levels did not vary according to alcohol consumption before or during pregnancy. High parity was associated with low serum folate. Folate levels and pregnancy outcome
There was no significant folate levels and pregnancy by neonatal characteristics age, birthweight, crown-heel
to alcohol
consumption
before
and during
pregnancy,
Serum folate
of alcoholic
before pregnancy Maternal age Parity Educational level Number of cigarettes during Number
of alcoholic
pregnancy
and other
maternal
characteristics
(multiple
Red cell folate
P
s (PI
P
P
s(P)
P
0.003 0.11 - 0.23 0.28
0.005 0.024 0.08 0.22
0.54 < 0.001 0.003 0.21
1.3 1.4 7.6 -0.6
0.4 1.9 6.2 18.1
0.003 0.46 0.22 0.97
- 0.019
0.019
0.34
- 4.5
1.5
0.004
0.001 0.10 - 0.20 0.23
0.007 0.02 0.07 0.21
0.88 < 0.001 0.007 0.29
1.1 1.8 7.2 - 7.2
0.6 1.9 6.3 18.3
0.06 0.35 0.25 0.69
- 0.02
0.02
0.39
- 3.9
1.5
0.01
drinks/week
per day
pregnancy
during pregnancy Maternal age Parity Educational level Number of cigarettes during
relationship between outcome, as assessed including gestational length, head circum-
IV
Folate levels in relation regression)
Number
(r = 0.17,
the first trimester
drinks/week
per day
linear
24 TABLE
V
Correlations
between
folate
levels during
Birth weight
Serum folate
0.02 a (245) b
Red cell folate
- 0.02 (238)
pregnancy
and neonatal
Crown heel length
characteristics
Head circumference
0.03
- 0.02
(245) - 0.07
(229)
0.05
0.03
(235)
- 0.05
(245)
(245)
- 0.08
(238)
0.09
0.09
(242)
Placental weight
Agpar score at 5 min
Agpar score at 1 min
0.04
(238)
(238)
(222)
a correlation coefficient b number of subjects
TABLE
VI
Multiple
regression
analysis
of birthweight
and folate
status
Serum folate (ng/ml)
Red cell folate (ng/ml) P
P
s(P)
P
P
Gestational age Mother’s age Parity Educational level (elementary/other) Number of cigarettes/day during pregnancy Mother’s weight Mother’s height Weight gain during pregnancy
150 -0.4 50.1 -6.5 - 15.3 9.3 8.2 19.7
17 6.8 21.6 62.8 5.4 2.7 4.8 5.6
< 0.001 0.95 0.02 0.91 0.005 < 0.001 0.09 < 0.001
149 -0.9 56.2 -22.1 - 15.9 9.4 7.4 20.5
18 6.7 22.1 65.1 5.6 2.7 5.0 5.8
< 0.001 0.89 0.01 0.73 0.005 < 0.001 0.13 < 0.001
Number of alcoholic drinks by week in first trimester of pregnancy Folate
-4.8 3.2
2.0 18
0.016 0.86
-4.5 -0.1
2.0 -0.6
0.02 0.53
ference, Apgar scores at 1 and 5 min and placental weight, either before adjustment for potential confounders (Table V) or after adjusting. Table VI shows the relation between folate levels and birthweight after adjustment. Comparison of women with low levels of serum and red cell folates (< 2.5 and < 250 ng/ml, respectively) with women with normal levels also showed no significant association between folate levels and pregnancy outcome. Birthweight was associated with low alcohol consumption during the first trimester of pregnancy, after adjustment for other maternal risk factors and folate status. Other pregnancy outcome variables were not related to alcohol consumption after such adjustment.
s(P)
Discussion Serum and red cell folate values were positively correlated. Regression analysis showed that red cell folate was significantly related to alcohol consumption before pregnancy, even after adjustment for potential confounders; red cell folate values were negatively related to daily cigarette consumption during pregnancy. Serum folate levels were not related to alcohol consumption either before or during pregnancy. However, serum folate levels were lower for young mothers, and women with high parity. Folate status was not related to any pregnancy outcome variable. After adjustment, birthweight was negatively associated to alcohol consumption during the first trimester of pregnancy.
2s
Twenty-eight percent of women had no blood sample collection. However, the maternal charateristics and pregnancy outcome of these women did not differ from those of the women for whom blood samples were collected. Folate values did not vary according to the stage of pregnancy at blood collection, but most blood samples were collected during the third trimester of pregnancy. Anemia was observed in 22% of the women; this high proportion was due to the generally low socio-economic status of the sample. As the sample was designed to overrepresent the heaviest drinkers, it was not representative of the pregnant women who normally attend the Roubaix hospital antenatal clinics, and the proportion of women of low socioeconomic status was higher than usual. The women with anemia had lower serum folate than non anemic women; as shown in other studies on folate levels and hemoglobin, low folic acid can affect the hemoglobin level 15,131.The positive correlation already mentioned between serum and red cell folates was also found by others [7,14,15,16]. Here, serum folate values seemed low, and red cell folate levels better conserved. The usual threshold for folate deficiency was not applicable to the present results, because the assay method used gave different folates values than those by other methods, especially non-isotopic methods (D’Herbomez, personal communication). However, the augmented requirement for folates at the end of the pregnancy might be reflected by a decrease in serum folate only, without affecting red cell folate [6,14]. Serum folate is an earlier indicator of folic acid deficiency than red cell folate; red cell folate is considered as an indicator of long-term folate status, while serum folate reflects recent dietary intake of folic acid. In this study, serum and red cell folates were positively correlated with MCV, whereas we expected a negative correlation because high folic acid deficiency leads to macrocytosis. However, folate deficiency is often associated with iron deficiency which leads to microcytosis (i.e., a reduction in MCV) and may mask the macrocytosis [7]. Besides, alcohol consumption tended to increase MCV. Here some women may had have iron deficiency, as 22% of them were anemic.
Serum folate was lower in young women and women with high parity. These risk factors have been often been incriminated for folic acid deficiency [17]. A possible explanation is that women with repeated pregnancies do not have time to reconstitute their folate balance and young women have lower folate dietary intake. Cigarette smoking has been little studied in relation to folates during pregnancy; dietary intake of folate is smaller in heavy smokers [18,19]. In our study, socioeconomic status, represented by the educational level, was not significantly related to folate values, after adjustment for alcohol consumption, mother’s age, parity and cigarette consumption. In other studies of folate status and maternal risk factors, adjustment was rarely made [20,21]. Taken together, our findings seem consistent with those reported in the literature for maternal risk factors. In addition, we found a correlation between cigarette consumption and red cell folate. We found no relation between serum folate and alcohol consumption, while red cell folate was positively correlated with the quantity of consumed alcohol. In general, alcohol abusers have low folate levels, due to low dietary folate intake and the effect of alcohol on folate metabolism [22]. However, when beer consumption only was considered, red cell folate rose with the quantity of beer consumed. Wu [23] showed that alcohol abusers who only drank wine or spirits had lower folate levels than those drinking beer, probably because beer contains folic acid and can be an important source of this vitamin for heavy drinkers [8]. In our study, we were not able to distinguish between the effects of different types of beverage, as 80% of alcohol consumed was beer and most of the women drank different types of alcohol beverages. As already stated, the folic acid contained in beer might explain the positive relation we found between red cell folate and alcohol consumption. We had no information about other folate dietary intake. However, there was no correlation between folate levels and indicators of total dietary intake such as prepregnancy maternal weight, or weight gain during pregnancy. To our knowledge, there is no other study of the relationship between alcohol consumption and folate levels during pregnancy.
26
Here, the outcome of pregnancy was not related to folate levels. In animal experiments, ethanol was found to be piacentotoxic and specific folate receptor activity dropped significantly in the ethanol-exposed tissue [24]; it was also shown in beagles that large ethanol consumption and small protein intake could independently of each other depress pup birthweight and maternal red cell folate [25]. Baumslag et al. [26] showed that folate supplementation raised the birthweight of children born to black African women but did not affect the babies of better fed white women living in the same country. Four studies showed that folate supplementation increased birthweight [5,26-281, placental weight [5,27,28] or duration of pregnancy [5]. Two of these studies were conducted in industrial countries [5,27] and two in developing countries 126,281. However, other studies did not show these findings [29-311. Investigations in which groups of women with folate deficiency were compared with a control group showed that birthweight was smaller [33361 or gestation shorter (5,351 in the group with folate deficiency. On the whole, the literature tends to show that folate status does affect the outcome of pregnancy, mostly in populations with a high prevalence of folate deficiency and that folate supplementation is effective in populations who live in developing countries or whose socioeconomic status is low. In conclusion, our study showed that cigarette consumption, which is frequent during pregnancy, was associated with a decrease in red cell folate, although this association requires further confirmation. Beer consumption was associated with enhanced red cell folate. However, this relationship between one particular type of alcohol consumption on folate status must be explored in women consuming other types of beverages. In addition to an apparently positive effect on red cell folate, high alcohol consumption also had negative effects during pregnancy, especially on its outcome, and these effects should not be ignored. Acknowledgements
We thank C. Klein Bertrand who coordinated the study, 0. Klein and D. Subtil for their contri-
bution in data collection, A. Hennion and M. Franczuk for their help in the use of the hospital records, the biology laboratory (A. Bonte), the staff of the Maternity Department, G. Potier de Courcy for her help with the literature, and M. Dreyfus for her confribution in the preparation of the manuscript. The analysis was carried out at the INSERM Computer Center (SC5). The study was partly funded by the ‘Haut ComitC d’Etude et dInformation sur l’Alcoolisme’, contract No. 1984-64. It is part of the CEE Concerted Action on “Maternal alcohol consumption and its effects on pregnancy and child development - EUROMAC”. References 1 Bailey L, Cerda J. Iron and folate nutriture during life cycle. World Rev Nutr Diet 1988;56:56-92. 2 Fleming AF. Urinary excretion of folate in pregnancy. J Obstet Gynaecol Br Commonw 1979;79:916-922. 3 Huber M, Wallins LL, DeRusso P. Folate nutrition in pregnancy. J Am Diet Assoc 1988;7:791-795. 4 Milunsky A, Jick H, Jick S et al. Multivitamin folic acid suplementation in early pregnancy reduced the prevalence of neural tube defects. JAMA 1989;20:28-47. 5 Tchernia G, Blot I, Rey A, Kaltwasser JP, Zittoun J, Papiernik E. Maternal folate status, birthweight and gestational age. Dev Pharmacol Ther 1982;4:58-65. 6 Shojania AM. Folic acid and vitamin B12; deficiency in pregnancy and in the neonatal period. Clin Perinatal 1984;11:433-459. 7 Chanarin I. Folate and cobalamin. Haematology 1985;14: 629-641. 8 Herbert V, Zalusky R, Davidson C. Correlation of folate deficiency with alcoholism and associated macrocytosis, anemia, and liver disease. Ann Int Med 1963;58:977-987. 9 Lambie D, Johnson R. Drugs and folate metabolism. Drugs 1985;30:145-155. 10 Henderson G, Patwardhan R, Hoyumpa A, Schenker S. Foetal alcohol syndrome: overview of pathogenesis. Neurobehav Toxicol Teratol 1981;3:73-80. 11 Kaminski M, Rostand A, Lelong N, Dehaene P, Delestret I, Klein-Bertrand, Querleu D, Crepin G. Consommation d’alcool pendant la grossesse et caracteristiques nbonatales. J Alcool 1989;1:35-46. 12 Kramer MS. Intrauterine growth and gestational duration determinants. Pediatrics 1987;80:502-511. 13 Ek J. Plasma and red cell folate in mothers and infants in normal pregnancies. Acta Obstet Gynecol Stand 1982;61:17-20. 14 EK J. Plasma and red cell folate values in newborn infants and their mothers in relation to gestational age. J Pediatrics 1980;97:288-292.
27
18
19
20
21
22 23
24
25
Hercberg S, Bichon L. Galan P, Christians J, Carroget C, Potier de Courcy G. Iron and folacin status of pregnant women. Relationships with dietary intakes. Nutr Rep Intern 1987;35:915-930. Hoffbrand AV, Newcombe BFA, Mollin DL. Method of assay of red cell folate activity and the value of assay as a test for folate deficiency. J Clin Pathol 1966;19:17-25. King JC. Bronstein MN. Fitch WL, Weiniger J. Nutrient utilization during pregnancy. World Rev Nutr Diet 1987;52:71-142. Rogozinski H, Ankers C, Lennon D, Wild J, Schorah C, Sheppard S, Smithells RW. Folate nutrition in early pregnancy. Hum Nutr: Appl Nutr 1983;37A:357-364. Haste FM, Brooke 0, Anderson M et al. Nutrient intakes during pregnancy: observation on the influence of smoking and social class. Am J Clin Nutr 1990;51:29-36. Ho CH, Yuan CL, Yem SH. Serum folate levels in normal full term pregnant Chinese women. Acta Obstet Gynecol Stand 1988;67:417-20. Herbert V, Colman N, Spivack M, Ocasio E, Ghanta V, Kimmel K, Brenner L, Scott J. Folic acid deficiency in the United States: folate assays in a prenatal clinic. Am J Obstet Gynecol 1979;123:175-179. Hillman R, Steinberg S. The effects of alcohol on folate metabolism. Annu Rev Med 1982;33:345-351. Wu A, Chanarin I, Slavin G, Levi AJ. Folate deficiency in the alcoholic - its relationship to clinical and haematological abnormalities, liver disease and folate stores. Br J Haematol 1975;29:469-478. Fisher SE, Inselman S, Duffy L, Atkensis M, Spencer M, Benedict C. Ethanol and fetal nutrition: effect of chronic ethanol exposure on rat placental growth and membrane associated folic and receptor binding activity. J Pediatr Gastroenterol Nutr. 1985;4:645-649. Schwitzer B, Anderson J, Pick J. Effects of dietary preterm
26
27
28
29 30 31
32
33
34
35
36
and ethanol intake on pregnant beagles fed purified diets. J Nutr 1986;116:689-697. Baumslag N, Edelstein J, Metz J. Reduction of incidence of prematurity by folic acid supplementation in pregnancy. Br Med J 1970;i:lh-17. Rolschau J, Date J, Kristoffersen K. Folic acid supplement and intrauterine growth. Acta Obstet Gynecol Stand 1979;58:343-346. lyengar L, Rajalakshmi K. Effect of folic acid supplements on birthweights of infants. Am J Obstet Gynecol 1975;122:332-336. lyengar L. Folic acid requirements of Indian pregnant women. Am J Ohstet Gynecol 1971;111:13-16. Iyengar L, Apte SV. Prophilaxis of anemia in pregnancy. Am J Clin Nutr 1970;23:725-730. Fletcher J, Gurr A, Fellingham FR. Prankerd AJ, Brant HA, Menzies DN. The value of folic acid supplements in pregnancy. J Obstet Gynaecol Br Emp 1971;78:781-785. Fleming AF, Martin JD, Hahnel R, Westake AJ. Effects of iron and folic acid antenatal supplements on maternal haematology and foetal well being. Med J Austr 1974;2:429-436. Gandy G, Jacobson W. Influence of folic acid on birthweight and growth of the erythroblastotic infant. I Birthweight. Arch Dis Child 1977;52:1-6. Rae PG, Rob PM. Megaloblastic anaemia of pregnancy: a clinical and laboratory study with particular reference to the total and labile serum folate levels. J Clin Pathol 1970;23:379-391. Hunt IF. Murphy NJ, Card BK, Jacob M. Dietary folic acid intake and infant birthweights of pregnant women with low and acceptable red cell folate levels. Fed Proc 1979;38:711-715. Hibbard BM. Folates and the foetus. S Afr Med J 1975:49:1223X1220.