Nutrient intake and hypertensive disorders of pregnancy: Evidence from a large prospective cohort. Twinning rates and survival of twins in rural Nepal. The higher rate of multiple births after periconceptional multivitamin supplementation: an analysis of causes. Vitamin C and E supplementation in women at high risk for preeclampsia: a double-blind, placebo-controlled trial. Dietary factors and risk of spontaneous abortion. Incidence and outcome of bleeding before the 20th week of pregnancy: prospective study from general practice Reduction of Incidence of Prematurity by Folic Acid Supplementation in Pregnancy Differing effects of low and high bulk maternal dietary supplements during pregnancy. Frequency of abnormal karyotypes among abortuses from women with and without a history of recurrent spontaneous abortion.
OBJECTIVE The objective of this analysis was to prospect ively determine the effects of nutrient intakes on the incidences of  preeclampsia and pregnancy-associated hypertension among women enrolled in the Calcium for Preeclampsia Prevention study . STUDY DESIGN This was a prospect i ve observational cohort study of women in a r and omized clinical trial that included women seeking prenatal care at university medical centers and affiliated clinics and hospitals in 5 US communities . A total of 4589 nulliparous women were recruited between 13 and 21 weeks ' gestation .  Preeclampsia and pregnancy-associated hypertension were the main outcome measures . RESULTS Preeclampsia was noted in 326 ( 7.6 % ) of the 4314 women with known pregnancy outcomes followed up until > or = 20 weeks ' gestation , and pregnancy-associated hypertension was noted in 747 ( 17.3 % ) . As previously reported , there was no significant difference in these outcomes between cohorts r and omly assigned to supplementation with calcium or placebo . By means of logistic regression a baseline risk model was constructed for preeclampsia and pregnancy-associated hypertension . After adjustment for treatment and clinical site , body mass index > 26 kg/m(2 ) and race were significantly associated with an increased risk of preeclampsia . Body mass index > or = 35 kg/m(2 ) , race , and never smoking were significantly associated with an increased risk of pregnancy-associated hypertension . After adjustment for baseline risks , none of the 28 nutritional factors analyzed were significantly related to either preeclampsia or pregnancy-associated hypertension . CONCLUSION We found no evidence in this study for a significant association of hypertensive disorders of pregnancy  with any of the 23 nutrients measured BACKGROUND Twin pregnancies are common but there are few data on rates of twinning or survival of  liveborn twin infants  in developing countries . METHODS The rates of multiple births were calculated in a population -based cohort of married women of childbearing age who were enrolled in a r and omized community trial to assess the impact of vitamin A or beta-carotene on maternal and infant health and survival . RESULTS The rate of twinning was 16.1 per 1000 pregnancies ( 7.4 if only twin pregnancies result ing in two liveborn infants were used ) . The rate for triplets and quadruplets was 0.19 and 0.06 per 1000 pregnancies . Twinning rates were higher among women of higher parity , but were not associated with maternal age . Twinning rates among twins where at least one was live born ( or increased in utero survival ) were 30 % ( 95 % CI : -1 % , 71 % ) and 44 % ( 95 % CI : 9 % , 89 % ) higher among women receiving vitamin A and beta-carotene supplements than placebo , after adjusting for maternal age , gestational age , and parity . The perinatal mortality rate was 8.54 times higher for twins than singletons , 7.32 higher for neonatal mortality , and 5.84 higher for cumulative 24-week mortality . This difference was reduced but not erased by adjusting for gestational age . No difference in survival of liveborn twin infants was seen by supplement group . A higher mortality rate among male twins was largely explained by gestational age . CONCLUSIONS Multiple births are relatively common occurrences in rural Nepal , and carry a much higher mortality risk for the infants than for singletons . Vitamin A or beta-carotene supplementation appeared to increase the rate of twinning , or improve the survival of twins in utero , but did not increase twin survival after birth A r and omized controlled trial of periconceptional multivitamin supplementation ( including 0.8 mg folic acid -- see the Material s and Methods section for the precise composition of the multivitamin and trace-element supplementation ) was carried out for at least 28 days before conception . The trial was continued until at least until the second missed menstrual period to test the effectiveness of this new primary preventive method in the reduction of neural tube defects . However , other pregnancy outcomes were also evaluated . Of a total of 5,502 pregnant women , 4,846 births were analysed in the final data base . The rate of multiple births was significantly higher in the multivitamin group ( 3.8 % ) than in the placebo-like trace-element control group ( 2.7 % ) , and in both groups exceeded the multiple birth rate of 2.2 % in the Hungarian population at large . 7.3 % of women in the multivitamin and 7.9 % of women in the trace-element groups had received ovarian stimulation treatment ( mainly clomiphene ) for hormonal dysfunctions , eg . anovulation . Nonetheless , our study showed that periconceptional multivitamin supplementation , with or without ovarian stimulation , increases the rate of multiple births OBJECTIVE We sought to determine the effect of supplemental antioxidant vitamins C and E on the rate of preeclampsia in high-risk pregnant women . STUDY DESIGN Women at risk for preeclampsia ( previous preeclampsia , chronic hypertension , pregestational diabetes , or multifetal gestation ) were recruited at 14 to 20 weeks ' gestation and r and omly assigned to receive either 1000 mg of vitamin C and 400 IU of vitamin E or placebo daily in addition to their regular prenatal vitamins . The primary outcome was the occurrence of preeclampsia . An estimated sample size of 220 women in each arm was determined to be necessary to demonstrate a 50 % reduction in the rate of preeclampsia . RESULTS Funding was terminated after 109 women had been recruited ; 9 were lost to follow-up or withdrew . We analyzed data from the remaining 100 women to look for differences in outcome and to estimate the required sample size for future studies . The rate of preeclampsia was not different : 17.3 % in women who received supplemental vitamins C and E , versus 18.8 % in the placebo group . Assuming a baseline rate of preeclampsia in the placebo group between 15 % and 20 % , we can estimate that 500 to 950 women in each arm will be required to show a clinical ly important reduction in the rate of preeclampsia . CONCLUSION The potential benefit of vitamin C and E supplementation to prevent  preeclampsia in women with clinical risk factors is smaller than we estimated . Future studies of antioxidant vitamin supplementation in this population will require more than 500 women in each arm OBJECTIVE This study examines the association between dietary habits and risk of spontaneous abortion .  DESIGN Hospital-based case-control study . SETTING Obstetric hospitals in Milan , Italy . SUBJECTS Cases were : 912 women admitted for spontaneous abortion ( within the 12th week of gestation ) . Controls were : women who gave birth at term to healthy infants on r and omly selected days at the same hospitals where cases had been identified . RESULTS The risk of spontaneous abortion was inversely and significantly related to green vegetables , fruit , milk , cheese , eggs and fish consumption . The multivariate odds ratios ( OR ) , for highest versus lowest levels of intake , were 0.3 for fruit , 0.5 for cheese , 0.6 for green vegetables and milk and 0.7 for fish and eggs . The major type of seasoning fats have showed a direct association with risk of miscarriage . Comparing the highest with the lowest intake , the ORs were 2.0 ( 95 % confidence interval , CI 1.1 - 3.6 ) and 1.6 ( 95 % CI 1.1 - 2.3 ) for butter and oil , respectively . No consistent association emerged between meat , liver , ham and carrots intake and the risk of spontaneous abortion . CONCLUSIONS This result suggests that a diet poor in several aspects , including vegetables and fruit , milk and dairy products , but rich in fats , may be a determinant or a correlate of increased risk of spontaneous abortion Abstract Objective : To estimate the miscarriage rate in a cohort of pregnant women and the final outcome of pregnancy . Design : Two year prospect i ve community study . Setting : Women registered with four semirural practice s at one health centre . Subjects : 626 pregnant women from a population 21 448 , 5140 of whom were women aged 15 - 44 years . Main outcome measures : Vaginal bleeding and outcome of pregnancy . Results : 76 of the 89 women with an unwanted pregnancy requested a termination . In the 550 ongoing pregnancies bleeding occurred before the 20th week in 117 ( 21 % ) , and 67 ( 12 % ) ended in miscarriage . The risk of miscarriage was not significantly increased after a miscarriage in the previous pregnancy ( 11 ( 15 % ) women had miscarriage v 55 ( 12 % ) women who had not had miscarriage ) who had previously had a live birth ) . Of the 117 women with  bleeding  , 64 were not admitted to hospital by the general practitioner ; 42 of these women had an ultrasound examination at the health centre and 19 subsequently miscarried at home . In hospital 41 of 46 women who miscarried had evacuation of the uterus . Conclusions : Bleeding occurred in one fifth of recognised pregnancies before the 20th week and over half of these miscarried . Treatment of women with miscarriage at home means current statistics on miscarriage in Britain are missing many cases . Key messages No national statistics for Britain are published on miscarriages Extrapolations from this survey indicate that in 1993 there may have been 70 000 - 90 000 miscarriages in Engl and and Wales Bleeding in early pregnancy is followed by a live birth in about half the affected pregnancies At least a quarter of all miscarriages were treated at home by general practitioners and would therefore not be recorded in any published statistics Women who had had a miscarriage did not have a significantly higher chance of a second consecutive Folic acid administered to pregnant Bantu , whose diet is low in folate , was associated with a significant reduction in the incidence of prematurity . No such effect could be demonstrated in White patients subsisting on an average Western diet . This suggests that folate deficiency may contribute to the “ pregnancy wastage ” in population s whose dietary folate intake is low , and is a further indication for folic acid supplementation during pregnancy in these groups The study attempted to determine if the bulk of dietary supplements given to pregnant women after midgestation affects fetal growth .  127 Zulu women were r and omly assigned to four groups , two of which received daily food supplements design ed to raise their energy , protein and vitamin intakes to levels recommended by the U.S. Food and Nutrition Board . One of these supplements had a high bulk , the other a low bulk . The third supplement contained only zinc and the fourth a placebo . Women in all four groups had a similar weight gain and length of gestation . Birth weights were from 6.5 to 9.5 % greater with the low bulk than with the other supplements OBJECTIVE To compare the frequency of chromosomal abnormalities in products of conception from women with and without a history of recurrent spontaneous abortion . DESIGN Retrospective analysis of prospect ively collected material . SETTING Private practice at the Genetics and IVF Institute , Fairfax , Virginia and Grupo de Reproducción AGY Asociados , México City , México . PATIENTS Women with ( n = 94 ) and without ( n = 130 ) a history of recurrent spontaneous abortion who had a spontaneous abortion between January 1 , 1992 and November 1 , 1994 . INTERVENTION  Chromosomal analysis performed on products of conception using st and ard G-b and ing technique . MAIN OUTCOME MEASURE The percentage of chromosomal abnormalities among products of conception from women with and without recurrent spontaneous abortion was compared . RESULTS Among products of conception from women with recurrent spontaneous abortion , 57 % ( 54/94 ) had abnormal and 43 % ( 40/94 ) had normal chromosome analyses . Products of conception from women without recurrent spontaneous abortion had abnormal chromosome analyses in 57 % ( 74/130 ) and normal results in 43 % ( 56/130 ) . CONCLUSIONS No differences in frequency of abnormal karyotype were observed in products of conception from women with recurrent spontaneous abortion compared with women without recurrent spontaneous abortion
BACKGROUND  Miscarriage  is a common complication of pregnancy that can be caused by a wide range of factors .
Poor dietary intake of vitamins has been associated with an increased risk of miscarriage , therefore supplementing women with vitamins either prior to or in early pregnancy may help prevent miscarriage .
OBJECTIVES The objectives of this review are to determine the effectiveness and safety of any vitamin supplementation , on the risk of  spontaneous miscarriage , maternal adverse outcomes and fetal and infant adverse outcomes .
SELECTION CRITERIA All r and omised and quasi-r and omised trials comparing one or more vitamins with either placebo , other vitamins , no vitamins or other interventions , prior to conception , periconceptionally or in early pregnancy ( less than 20 weeks ' gestation ) .