Vitamin D supplementation in pregnancy

Daily versus stat vitamin D supplementation during pregnancy; A prospective cohort study

BACKGROUND

Despite favorable climatic conditions, vitamin D deficiency (VDD) is widespread in Pakistan. Current study was aimed to evaluate the prevalence of VDD in Pakistani pregnant women and effectiveness of various regimen of Vitamin D supplementation.

METHODOLOGY

This hospital-based prospective cohort study included pregnant women at 12th to 24th weeks of gestation attending Gynae clinic from October 2018 to April 2019. Patients were classified into control and treatment groups (Groups: G1, G2 and G3) according to the dose of vitamin D supplementation. Patients received various regimens of vitamin D including 2000 IU/day (G1), 5000 IU/day (G2) and stat 200000 IU (G3). The levels of vitamin D were measured before and after supplementation. The effectiveness of dosages were compared between and within the groups. Moreover, factors associated with vitamin D sufficiency and insufficiency were ascertained using appropriate statistical methods.

RESULTS

Among 281 pregnant women (mean age: 28.22 ± 4.61 years), VDD was prevalent in 47.3% cases. Vitamin D supplementation caused significant rise in the levels 25(OH)D in treatment groups, while there was no significant difference in control group. The highest mean increment in vitamin D (23.14 ± 11.18 ng/ml) was observed with dose 5000 IU/day followed by doses 200000 IU stat (21.06 ± 13.73 ng/ml) and 2000 IU/day (10.24 ± 5.65 ng/ml). Vitamin D toxicity was observed in one patient who received 200000 IU stat of vitamin D. The frequency of VDD following the supplementation was 5.7%. Education status, duration of sun exposure and use of sunblock was substantially associated with vitamin D sufficiency in the current study.

CONCLUSION

Our findings underscore the high proportion of VDD among pregnant women in Pakistan. Maternal vitamin D supplementation substantially improved the levels of 25(OH)D. Of three used regimens, the dose of 5000 IU/day is considered safe and equally effective as of 200000 IU stat. Since pregnancy is a time of tremendous growth and physiological changes for mother and her developing fetus with lifelong implications for the child, gestational vitamin D supplementation should be considered to ensure the optimal vitamin D accrual in pregnant women. This study generates the hypothesis that vitamin D supplementation at a dose of 5000 IU/day during pregnancy is superior to the other regimens. However, well-controlled randomized trials are needed to confirm these findings.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D supplementation during pregnancy may be needed to protect against adverse pregnancy outcomes. This is an update of a review that was first published in 2012 and then in 2016.

OBJECTIVES

To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

For this update, we searched Cochrane Pregnancy and Childbirth's Trials Register (12 July 2018), contacted relevant organisations (15 May 2018), reference lists of retrieved trials and registries at clinicaltrials.gov and WHO International Clinical Trials Registry Platform (12 July 2018). Abstracts were included if they had enough information to extract the data.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of trials against the inclusion criteria, ii) extracted data from included trials, and iii) assessed the risk of bias of the included trials. The certainty of the evidence was assessed using the GRADE approach.

MAIN RESULTS

We included 30 trials (7033 women), excluded 60 trials, identified six as ongoing/unpublished trials and two trials are awaiting assessments.Supplementation with vitamin D alone versus placebo/no interventionA total of 22 trials involving 3725 pregnant women were included in this comparison; 19 trials were assessed as having low-to-moderate risk of bias for most domains and three trials were assessed as having high risk of bias for most domains. Supplementation with vitamin D alone during pregnancy probably reduces the risk of pre-eclampsia (risk ratio (RR) 0.48, 95% confidence interval (CI) 0.30 to 0.79; 4 trials, 499 women, moderate-certainty evidence) and gestational diabetes (RR 0.51, 95% CI 0.27 to 0.97; 4 trials, 446 women, moderate-certainty evidence); and probably reduces the risk of having a baby with low birthweight (less than 2500 g) (RR 0.55, 95% CI 0.35 to 0.87; 5 trials, 697 women, moderate-certainty evidence) compared to women who received placebo or no intervention. Vitamin D supplementation may make little or no difference in the risk of having a preterm birth < 37 weeks compared to no intervention or placebo (RR 0.66, 95% CI 0.34 to 1.30; 7 trials, 1640 women, low-certainty evidence). In terms of maternal adverse events, vitamin D supplementation may reduce the risk of severe postpartum haemorrhage (RR 0.68, 95% CI 0.51 to 0.91; 1 trial, 1134 women, low-certainty evidence). There were no cases of hypercalcaemia (1 trial, 1134 women, low-certainty evidence), and we are very uncertain as to whether vitamin D increases or decreases the risk of nephritic syndrome (RR 0.17, 95% CI 0.01 to 4.06; 1 trial, 135 women, very low-certainty evidence). However, given the scarcity of data in general for maternal adverse events, no firm conclusions can be drawn.Supplementation with vitamin D and calcium versus placebo/no interventionNine trials involving 1916 pregnant women were included in this comparison; three trials were assessed as having low risk of bias for allocation and blinding, four trials were assessed as having high risk of bias and two had some components having a low risk, high risk, or unclear risk. Supplementation with vitamin D and calcium during pregnancy probably reduces the risk of pre-eclampsia (RR 0.50, 95% CI 0.32 to 0.78; 4 trials, 1174 women, moderate-certainty evidence). The effect of the intervention is uncertain on gestational diabetes (RR 0.33,% CI 0.01 to 7.84; 1 trial, 54 women, very low-certainty evidence); and low birthweight (less than 2500 g) (RR 0.68, 95% CI 0.10 to 4.55; 2 trials, 110 women, very low-certainty evidence) compared to women who received placebo or no intervention. Supplementation with vitamin D and calcium during pregnancy may increase the risk of preterm birth < 37 weeks in comparison to women who received placebo or no intervention (RR 1.52, 95% CI 1.01 to 2.28; 5 trials, 942 women, low-certainty evidence). No trial in this comparison reported on maternal adverse events.Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D)One trial in 1300 participants was included in this comparison; it was assessed as having low risk of bias. Pre-eclampsia was not assessed. Supplementation with vitamin D + other nutrients may make little or no difference in the risk of preterm birth < 37 weeks (RR 1.04, 95% CI 0.68 to 1.59; 1 trial, 1298 women, low-certainty evidence); or low birthweight (less than 2500 g) (RR 1.12, 95% CI 0.82 to 1.51; 1 trial, 1298 women, low-certainty evidence). It is unclear whether it makes any difference to the risk of gestational diabetes (RR 0.42, 95% CI 0.10 to 1.73) or maternal adverse events (hypercalcaemia no events; hypercalciuria RR 0.25, 95% CI 0.02 to 3.97; 1 trial, 1298 women,) because the certainty of the evidence for both outcomes was found to be very low.

AUTHORS' CONCLUSIONS

We included 30 trials (7033 women) across three separate comparisons. Our GRADE assessments ranged from moderate to very low, with downgrading decisions based on limitations in study design, imprecision and indirectness.Supplementing pregnant women with vitamin D alone probably reduces the risk of pre-eclampsia, gestational diabetes, low birthweight and may reduce the risk of severe postpartum haemorrhage. It may make little or no difference in the risk of having a preterm birth < 37 weeks' gestation. Supplementing pregnant women with vitamin D and calcium probably reduces the risk of pre-eclampsia but may increase the risk of preterm births < 37 weeks (these findings warrant further research). Supplementing pregnant women with vitamin D and other nutrients may make little or no difference in the risk of preterm birth < 37 weeks' gestation or low birthweight (less than 2500 g). Additional rigorous high quality and larger randomised trials are required to evaluate the effects of vitamin D supplementation in pregnancy, particularly in relation to the risk of maternal adverse events.

Non-skeletal health effects of vitamin D supplementation: A systematic review on findings from meta-analyses summarizing trial data

BACKGROUND

A large number of observational studies have reported harmful effects of low 25-hydroxyvitamin D (25OHD) levels on non-skeletal outcomes. We performed a systematic quantitative review on characteristics of randomized clinical trials (RCTs) included in meta-analyses (MAs) on non-skeletal effects of vitamin D supplementation.

METHODS AND FINDINGS

We identified systematic reviews (SR) reporting summary data in terms of MAs of RCTs on selected non-skeletal outcomes. For each outcome, we summarized the results from available SRs and scrutinized included RCTs for a number of predefined characteristics. We identified 54 SRs including data from 210 RCTs. Most MAs as well as the individual RCTs reported null-findings on risk of cardiovascular diseases, type 2 diabetes, weight-loss, and malignant diseases. Beneficial effects of vitamin D supplementation was reported in 1 of 4 MAs on depression, 2 of 9 MAs on blood pressure, 3 of 7 MAs on respiratory tract infections, and 8 of 12 MAs on mortality. Most RCTs have primarily been performed to determine skeletal outcomes, whereas non-skeletal effects have been assessed as secondary outcomes. Only one-third of the RCTs had low level of 25OHD as a criterion for inclusion and a mean baseline 25OHD level below 50 nmol/L was only present in less than half of the analyses.

CONCLUSIONS

Published RCTs have mostly been performed in populations without low 25OHD levels. The fact that most MAs on results from RCTs did not show a beneficial effect does not disprove the hypothesis suggested by observational findings on adverse health outcomes of low 25OHD levels.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D deficiency or insufficiency is thought to be common among pregnant women. Vitamin D supplementation during pregnancy has been suggested as an intervention to protect against adverse pregnancy outcomes.

OBJECTIVES

To examine whether oral supplements with vitamin D alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (23 February 2015), the International Clinical Trials Registry Platform (31 January 2015), the Networked Digital Library of Theses and Dissertations (28 January 2015) and also contacted relevant organisations (31 January 2015).

SELECTION CRITERIA

Randomised and quasi-randomised trials with randomisation at either individual or cluster level, evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of studies against the inclusion criteria ii) extracted data from included studies, and iii) assessed the risk of bias of the included studies. Data were checked for accuracy. The quality of the evidence was assessed using the GRADE approach.

MAIN RESULTS

In this updated review we included 15 trials assessing a total of 2833 women, excluded 27 trials, and 23 trials are still ongoing or unpublished. Nine trials compared the effects of vitamin D alone versus no supplementation or a placebo and six trials compared the effects of vitamin D and calcium with no supplementation. Risk of bias in the majority of trials was unclear and many studies were at high risk of bias for blinding and attrition rates. Vitamin D alone versus no supplementation or a placebo Data from seven trials involving 868 women consistently show that women who received vitamin D supplements alone, particularly on a daily basis, had higher 25-hydroxyvitamin D than those receiving no intervention or placebo, but this response was highly heterogeneous. Also, data from two trials involving 219 women suggest that women who received vitamin D supplements may have a lower risk of pre-eclampsia than those receiving no intervention or placebo (8.9% versus 15.5%; risk ratio (RR) 0.52; 95% CI 0.25 to 1.05, low quality). Data from two trials involving 219 women suggest a similar risk of gestational diabetes among those taking vitamin D supplements or no intervention/placebo (RR 0.43; 95% CI 0.05, 3.45, very low quality). There were no clear differences in adverse effects, with only one reported case of nephritic syndrome in the control group in one study (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women, low quality). Given the scarcity of data for this outcome, no firm conclusions can be drawn. No other adverse effects were reported in any of the other studies.With respect to infant outcomes, data from three trials involving 477 women suggest that vitamin D supplementation during pregnancy reduces the risk preterm birth compared to no intervention or placebo (8.9% versus 15.5%; RR 0.36; 95% CI 0.14 to 0.93, moderate quality). Data from three trials involving 493 women also suggest that women who receive vitamin D supplements during pregnancy less frequently had a baby with a birthweight below 2500 g than those receiving no intervention or placebo (RR 0.40; 95% CI 0.24 to 0.67, moderate quality).In terms of other outcomes, there were no clear differences in caesarean section (RR 0.95; 95% CI 0.69 to 1.31; two trials; 312 women); stillbirths (RR 0.35 95% CI 0.06, 1.99; three trials, 540 women); or neonatal deaths (RR 0.27; 95% CI 0.04, 1.67; two trials, 282 women). There was some indication that vitamin D supplementation increases infant length (mean difference (MD) 0.70, 95% CI -0.02 to 1.43; four trials, 638 infants) and head circumference at birth (MD 0.43, 95% CI 0.03 to 0.83; four trials, 638 women). Vitamin D and calcium versus no supplementation or a placeboWomen who received vitamin D with calcium had a lower risk of pre-eclampsia than those not receiving any intervention (RR 0.51; 95% CI 0.32 to 0.80; three trials; 1114 women, moderate quality), but also an increased risk of preterm birth (RR 1.57; 95% CI 1.02 to 2.43, three studies, 798 women, moderate quality). Maternal vitamin D concentration at term, gestational diabetes, adverse effects and low birthweight were not reported in any trial or reported only by one study.

AUTHORS' CONCLUSIONS

New studies have provided more evidence on the effects of supplementing pregnant women with vitamin D alone or with calcium on pregnancy outcomes. Supplementing pregnant women with vitamin D in a single or continued dose increases serum 25-hydroxyvitamin D at term and may reduce the risk of pre-eclampsia, low birthweight and preterm birth. However, when vitamin D and calcium are combined, the risk of preterm birth is increased. The clinical significance of the increased serum 25-hydroxyvitamin D concentrations is still unclear. In light of this, these results need to be interpreted with caution. Data on adverse effects were lacking in all studies.The evidence on whether vitamin D supplementation should be given as a part of routine antenatal care to all women to improve maternal and infant outcomes remains unclear. While there is some indication that vitamin D supplementation could reduce the risk of pre-eclampsia and increase length and head circumference at birth, further rigorous randomised trials are required to confirm these effects.

Prenatal calcium and vitamin D intake, and bone mass in later life

The aging population will result in an increasing burden of osteoporotic fractures, necessitating the identification of novel strategies for prevention. There is increasing recognition that factors in utero may influence bone mineral accrual, and, thus, osteoporosis risk. The role of calcium and vitamin D has received much attention in recent years, and in this review, we will survey available studies relating maternal calcium and vitamin D status during pregnancy to offspring bone development. The evidence base supporting a positive influence on intrauterine skeletal growth appears somewhat stronger for maternal 25(OH)-vitamin D concentration than for calcium intake, and the available data point toward the need for high-quality randomized controlled trials in order to inform public health policy. It is only with such a rigorous approach that it will be possible to delineate the optimal strategy for vitamin D supplementation in pregnancy in relation to offspring bone health.

The role of vitamin D in pregnancy and lactation: emerging concepts

Pregnancy is a critical time in the lifecycle of a woman where she is responsible not only for her own well-being, but also that of her developing fetus, a process that continues during lactation. Until recently, the impact of vitamin D status during this period had not been fully appreciated. Data regarding the importance of vitamin D in health have emerged to challenge traditional dogma, and suggest that vitamin D - through its effect on immune function and surveillance - plays a role beyond calcium and bone metabolism on the health status of both the mother and her fetus. Following birth, this process persists; the lactating mother continues to be the main source of vitamin D for her infant. Thus, during both pregnancy and lactation, maternal deficiency predicts fetal and infant deficiency; the significance of this is just beginning to be understood and will be highlighted in this review.

Vitamin D during pregnancy and maternal, neonatal and infant health outcomes: a systematic review and meta-analysis

Vitamin D has well-defined classical functions related to calcium metabolism and bone health but also has non-classical effects that may influence other aspects of health. There has been considerable recent interest in the role of vitamin D on outcomes related to pregnancy and young child health but few efforts have been made to systematically consolidate this evidence to inform the research and policy agenda for low-income countries. A systematic review was undertaken to identify intervention and observational studies of vitamin D supplementation, intake or status (25-hydroxy-vitamin D) during pregnancy on perinatal and infant health outcomes. Data from trials and observational studies isolating the effect of vitamin D supplementation and intake were extracted and study quality was evaluated. Meta-analysis was used to pool effect estimates. We identified five randomised trials with outcomes of relevance to our review. All had small sample size and dosage amount, duration and frequency varied as did the ability to correct deficiency. Pooled analysis of trials using fixed-effects models suggested protective effects of supplementation on low birthweight (three trials, risk ratio (RR) = 0.40 [95% confidence interval (CI) 0.23, 0.71]) and non-significant but suggestive effects of daily supplementation on small-for-gestational age (two trials, RR = 0.67 [0.40, 1.11]). No effect on preterm delivery (<37 weeks) was evident (two trials, RR = 0.77 [0.35, 1.66]). Little evidence from trials exists to evaluate the effect of vitamin D supplementation during pregnancy on maternal, perinatal or infant health outcomes. Based on both trials and observational studies, we recommend that future research explore small-for-gestational age, preterm delivery, pre-eclampsia, and maternal and childhood infections, as outcomes of interest. Trials should focus on populations with a high prevalence of vitamin D deficiency, explore the relevance of timing of supplementation, and the dosage used in such trials should be sufficient to correct deficiency.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D deficiency or insufficiency is thought to be common among pregnant women. Vitamin D supplementation during pregnancy has been suggested as an intervention to protect against adverse gestational outcomes.

OBJECTIVES

To examine whether supplements with vitamin D alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve maternal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 October 2011), the International Clinical Trials Registry Platform (ICTRP) (31 October 2011), the Networked Digital Library of Theses and Dissertations (28 October 2011) and also contacted relevant organisations (8 April 2011).

SELECTION CRITERIA

Randomised and quasi-randomised trials with randomisation at either individual or cluster level, evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of studies against the inclusion criteria ii) extracted data from included studies, and iii) assessed the risk of bias of the included studies. Data were checked for accuracy.

MAIN RESULTS

The search strategy identified 34 potentially eligible references. We included six trials assessing a total of 1023 women, excluded eight studies, and 10 studies are still ongoing. Five trials involving 623 women compared the effects of vitamin D alone versus no supplementation/placebo and one trial with 400 women compared the effects of vitamin D and calcium versus no supplementation.Only one trial with 400 women reported on pre-eclampsia: women who received 1200 IU vitamin D along with 375 mg of elemental calcium per day were as likely to develop pre-eclampsia as women who received no supplementation (average risk ratio (RR) 0.67; 95% confidence interval (CI) 0.33 to 1.35). Data from four trials involving 414 women consistently show that women who received vitamin D supplements had higher concentrations of vitamin D in serum at term than those women who received no intervention or a placebo; however the magnitude of the response was highly heterogenous. Data from three trials involving 463 women suggest that women who receive vitamin D supplements during pregnancy less frequently had a baby with a birthweight below 2500 grams than those women receiving no treatment or placebo; statistical significance was borderline (RR 0.48; 95% CI 0.23 to 1.01).In terms of other conditions, there were no significant differences in adverse side effects including nephritic syndrome (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women); stillbirths (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women) or neonatal deaths (RR 0.17; 95% CI 0.01 to 4.06; one trial, 135 women) between women who received vitamin D supplements in comparison with women who received no treatment or placebo. No studies reported on preterm birth, maternal death, admission to neonatal intensive care unit/special nursery or Apgar scores.

AUTHORS' CONCLUSIONS

Vitamin D supplementation in a single or continued dose during pregnancy increases serum vitamin D concentrations as measured by 25-hydroxyvitamin D at term. The clinical significance of this finding and the potential use of this intervention as a part of routine antenatal care are yet to be determined as the number of high quality trials and outcomes reported is too limited to draw conclusions on its usefulness and safety. Further rigorous randomised trials are required to evaluate the role of vitamin D supplementation in pregnancy.

MAVIDOS Maternal Vitamin D Osteoporosis Study: study protocol for a randomized controlled trial. The MAVIDOS Study Group

MAVIDOS is a randomised, double-blind, placebo-controlled trial (ISRCTN82927713, registered 2008 Apr 11), funded by Arthritis Research UK, MRC, Bupa Foundation and NIHR.

Support during pregnancy for women at increased risk of low birthweight babies

BACKGROUND

Studies consistently show a relationship between social disadvantage and low birthweight. Many countries have programs offering special assistance to women thought to be at risk for giving birth to a low birthweight infant. These programs may include advice and counseling (about nutrition, rest, stress management, alcohol, and recreational drug use), tangible assistance (e.g., transportation to clinic appointments, household help), and emotional support. The programs may be delivered by multidisciplinary teams of health professionals, specially trained lay workers, or combination of lay and professional workers.

OBJECTIVES

The primary objective was to assess effects of programs offering additional social support compared with routine care, for pregnant women believed at high risk for giving birth to babies that are either preterm or weigh less than 2500 gm, or both, at birth. Secondary objectives were to determine whether effectiveness of support was mediated by timing of onset (early versus later in pregnancy) or type of provider (healthcare professional or lay woman).

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (January 2010).

SELECTION CRITERIA

Randomized trials of additional support during at-risk pregnancy by either a professional (social worker, midwife, or nurse) or specially trained lay person, compared to routine care. We defined additional support as some form of emotional support (e.g., counseling, reassurance, sympathetic listening) and information or advice or both, either in home visits or during clinic appointments, and could include tangible assistance (e.g., transportation to clinic appointments, assistance with care of other children at home).

DATA COLLECTION AND ANALYSIS

Two review authors evaluated methodological quality. We performed double data entry.

MAIN RESULTS

We included 17 trials (12,264 women). Programs offering additional social support for at-risk pregnant women were not associated with improvements in any perinatal outcomes, but there was a reduction in the likelihood of antenatal hospital admission (three trials; n = 737; RR 0.79, 95% CI 0.68 to 0.92) and caesarean birth (nine trials; n = 4522; RR 0.87, 95% CI 0.78 to 0.97).

AUTHORS' CONCLUSIONS

Pregnant women need the support of caring family members, friends, and health professionals. While programs which offer additional support during pregnancy are unlikely to prevent the pregnancy from resulting in a low birthweight or preterm baby, they may be helpful in reducing the likelihood of antenatal hospital admission and caesarean birth.

Vitamin D may be a link to black-white disparities in adverse birth outcomes

In the United States, significant, intractable disparities exist in rates of major pregnancy outcomes between non-Hispanic black and non-Hispanic white women. A previously unexplored candidate influence on the black-white disparity in adverse birth outcomes is maternal vitamin D status. This review summarizes the evidence relating maternal vitamin D to preeclampsia, spontaneous preterm birth, gestational diabetes, and fetal growth restriction, and addresses gaps in our understanding of the contribution of vitamin D to the intractable black-white disparity in these conditions. The literature reviewed highlights strong biologic plausibility of role for vitamin D in the pathophysiology of these poor pregnancy outcomes. Data also suggest that maternal vitamin D deficiency may increase the risk of preeclampsia and fetal growth restriction. Less research has been done in support of relations with spontaneous preterm birth and gestational diabetes, and fetal and infant survival have rarely been studied. Few trials of vitamin D supplementation have been conducted in pregnant women with adequate power to test effects on birth outcomes. Importantly, black pregnant women have rarely been studied in vitamin D-birth outcomes research. Although vitamin D is a promising candidate influence on black-white disparities in preeclampsia, spontaneous preterm birth, fetal growth restriction, and gestational diabetes, these associations require further study in large samples of black US women. Because vitamin D deficiency is widespread and black-white disparities in pregnancy outcomes and infant survival have been resistant to previous interventions, research to test vitamin D as a causal factor is of major public health significance.

TARGET AUDIENCE

Obstetricians & Gynecologist, Family Physicians.

LEARNING OBJECTIVES

After completion of this educational activity, the reader will be able to appreciate risk factors for inadequate vitamin D status. Understand the basic aspects of vitamin D metabolism. Become aware of recent literature linking inadequate vitamin D status and adverse pregnancy outcomes such as preeclampsia and preterm birth.

Evidence for perinatal and child health care guidelines in crisis settings: can Cochrane help?

BACKGROUND

It is important that healthcare provided in crisis settings is based on the best available research evidence. We reviewed guidelines for child and perinatal health care in crisis situations to determine whether they were based on research evidence, whether Cochrane systematic reviews were available in the clinical areas addressed by these guidelines and whether summaries of these reviews were provided in Evidence Aid.

METHODS

Broad internet searches were undertaken to identify relevant guidelines. Guidelines were appraised using AGREE and the clinical areas that were relevant to perinatal or child health were extracted. We searched The Cochrane Database of Systematic Reviews to identify potentially relevant reviews. For each review we determined how many trials were included, and how many were conducted in resource-limited settings.

RESULTS

Six guidelines met selection criteria. None of the included guidelines were clearly based on research evidence. 198 Cochrane reviews were potentially relevant to the guidelines. These reviews predominantly addressed nutrient supplementation, breastfeeding, malaria, maternal hypertension, premature labour and prevention of HIV transmission. Most reviews included studies from developing settings. However for large portions of the guidelines, particularly health services delivery, there were no relevant reviews. Only 18 (9.1%) reviews have summaries in Evidence Aid.

CONCLUSIONS

We did not identify any evidence-based guidelines for perinatal and child health care in disaster settings. We found many Cochrane reviews that could contribute to the evidence-base supporting future guidelines. However there are important issues to be addressed in terms of the relevance of the available reviews and increasing the number of reviews addressing health care delivery.

Vitamin D status during pregnancy and aspects of offspring health

Low maternal vitamin D levels during pregnancy have been linked to various health outcomes in the offspring, ranging from periconceptional effects to diseases of adult onset. Maternal and infant cord 25(OH)D levels are highly correlated. Here, we review the available evidence for these adverse health effects. Most of the evidence has arisen from observational epidemiological studies, but randomized controlled trials are now underway. The evidence to date supports that women should be monitored and treated for vitamin D deficiency during pregnancy but optimal and upper limit serum 25(OH)D levels during pregnancy are not known.

Vitamin D deficiency and supplementation during pregnancy

OBJECTIVE

Vitamin D is essential for skeletal health and prolonged deficiency results in infantile rickets and adult osteomalacia. The aim of this study is to determine the vitamin D status in pregnancy and to evaluate the effects of daily and of single-dose vitamin D supplementation.

DESIGN

A prospective randomized study at St Mary's Hospital London.

PATIENTS

A total of 180 women (Indian Asian, Middle Eastern, Black and Caucasian) were recruited at 27 weeks gestation and randomized into three treatment groups: a single oral dose of 200,000 IU vitamin D, a daily supplement of 800 IU vitamin D from 27 weeks until delivery and a no treatment group.

MEASUREMENTS

Vitamin D (25-hydroxyvitamin D), PTH and corrected calcium levels in mothers at 27 weeks and at delivery and cord 25-hydroxyvitamin D and corrected calcium levels.

RESULTS

The final maternal 25-hydroxyvitamin D levels were significantly higher in the supplemented group [daily dose (median) 42 (IQR 31-76) nmol/l, stat dose (median) 34 (IQR 30-46) nmol/l vs. median 27 (IQR 27-39) nmol/l in the no treatment; P < 0.0001] and significantly fewer women with secondary hyperparathyroidism in the supplemented group (10% in daily dose vs. 12% in stat dose vs. 27% in the no treatment; P < 0.05). Cord 25-hydroxyvitamin D levels were significantly higher with supplementation [daily dose median 26 (IQR 17-45) nmol/l, stat dose median 25 (IQR 18-34) nmol/l vs. median 17 (IQR 14-22) nmol/l in no treatment; P = 0.001].

CONCLUSION

Single or daily dose improved 25-hydroxyvitamin D levels significantly. However, even with supplementation, only a small percentage of women and babies were vitamin D sufficient. Further research is required to determine the optimal timing and dosing of vitamin D in pregnancy.

The association between maternal periodontitis and low birth weight infants among Malay women

OBJECTIVES

Maternal periodontitis has been suggested as one of the risk factors for low birth weight (LBW) infants. The objective of this study was to determine the association between maternal periodontitis and LBW infants among Malay women.

METHODS

Screening periodontal examinations were carried out on all eligible Malay pregnant women in the second trimester of pregnancy attending two randomly selected community maternal and child health clinics in Kota Bharu, Kelantan. Patients with four or more sites with pocket depth 4 mm or higher, and clinical attachment loss 3 mm or higher at the same site with presence of bleeding on probing were diagnosed as having periodontitis in this study. Using this definition, systematic random sampling was utilized for selection of 250 subjects for each exposed and non-exposed group. Of 500 subjects enrolled in the study, 28 (5.6%) were either dropped or lost to follow-up. Of the remaining 472 subjects, 232 with periodontitis were in the exposed group and 240 with healthy periodontium were in the nonexposed group.

RESULTS

The incidence of LBW was 14.2% (95% CI: 9.70-18.75) in women with periodontitis, and 3.3% (95% CI: 1.05-5.62) in women without periodontitis. The relative risk of having LBW infants was 4.27 times higher for women with periodontitis compared with those without periodontitis (95% CI: 2.01-9.04). After adjustment for potential confounders using multiple logistic regression analysis, significant association was found between maternal periodontitis and LBW (OR = 3.84; 95% CI: 1.34-11.05).

CONCLUSION

The results of this study provide additional evidence that pregnant women with periodontitis are at a significantly higher risk of delivering LBW infants.

Maternal vitamin D status during pregnancy and child outcomes

OBJECTIVE

To investigate whether exposure to high maternal concentrations of 25(OH)-vitamin D in pregnancy poses any risk to the child.

DESIGN

Prospective study.

SETTING

Princess Anne Maternity Hospital, Southampton, UK.

SUBJECTS

A group of 596 pregnant women were recruited. A total of 466 (78%) children were examined at birth, 440 (74%) at age 9 months and 178 (30%) at age 9 years.

METHODS

Maternal 25 (OH)-vitamin D concentrations were measured in late pregnancy. Anthropometry of the child was recorded at birth, 9 months and 9 years. At 9 months, atopic eczema was assessed. At 9 years, children had an echocardiogram and a dual energy x-ray absorptiometry scan, blood pressure, arterial compliance and carotid intima-media thickness were measured and intelligence and psychological function assessed.

RESULTS

There were no associations between maternal 25(OH)-vitamin D concentrations and the child's body size or measures of the child's intelligence, psychological health or cardiovascular system. Children whose mothers had a 25(OH)-vitamin D concentration in pregnancy >75 nmol/l had an increased risk of eczema on examination at 9 months (OR 3.26, 95% CI 1.15-9.29, P=0.025) and asthma at age 9 years (OR 5.40, 95% CI, 1.09-26.65, P=0.038) compared to children whose mothers had a concentration of <30 nmol/l.

CONCLUSION

Exposure to maternal concentrations of 25(OH)-vitamin D in pregnancy in excess of 75 nmol/l does not appear to influence the child's intelligence, psychological health or cardiovascular system; there could be an increased risk of atopic disorders, but this needs confirmation in other studies.

High prevalence of vitamin D deficiency in newborn infants of high-risk mothers

OBJECTIVE

To determine the prevalence of vitamin D deficiency in newborn infants of mothers at risk of vitamin D deficiency because of dark skin or the wearing of concealing clothes (such as a veil) compared with a group presumed not to be at risk. A second aim was to correlate these newborn infants' vitamin D concentrations with biochemical parameters of vitamin D metabolism and bone turnover at birth.

DESIGN

A prospective study conducted between April 2004 and February 2006 including women delivering during this period and their newborn infants.

SETTING

The outpatient clinic of the obstetrics department, Sint Franciscus Gasthuis, Rotterdam, the Netherlands.

PATIENTS

Eighty seven newborn infants of healthy mothers with either dark skin and/or concealing clothing (risk group) or light skin (control group).

RESULTS

We found a significant difference in the prevalence of vitamin D deficiency (25-hydroxyvitamin D(3) <25 nmol/l) between newborn infants of mothers at risk and those of mothers in the control group (63.3% vs 15.8%; p<0.001). Mean alkaline phosphatase concentrations were significantly higher in the at risk group.

CONCLUSIONS

Newborn infants of mothers with dark skin or wearing concealing clothes are at great risk of vitamin D deficiency at birth. The clinical implications are unknown. Further research is necessary to determine the long-term consequences of maternal and neonatal vitamin D deficiency so that guidelines on vitamin D supplementation during pregnancy can be issued.

Type 1 diabetes: pathogenesis and prevention

Type 1 diabetes results from the autoimmune destruction of insulin-producing beta cells in the pancreas. Genetic and, as yet undefined, environmental factors act together to precipitate the disease. The excess mortality associated with the complications of type 1 diabetes and the increasing incidence of childhood type 1 diabetes emphasize the importance of therapeutic strategies to prevent this chronic disorder. Why is it considered that type 1 diabetes might be preventable? Different strands of diabetes research are coming together to suggest therapeutic targets. Islet cell autoantibody assays make it possible to accurately identify people at risk of future disease. In most cases, a long prodrome provides a window of opportunity to reverse the autoimmune process. Although no current "cure" exists, recent genetic data and preliminary trial results suggest T cells as a target for preventive strategies. Another potentially attainable target is induction of tolerance to the beta-cell proteins such as insulin that are inappropriately recognized. Other strategies involve beta-cell replacement, but currently there are insufficient donor cells available. This may be overcome as the processes controlling the differentiation of pancreatic and nonpancreatic progenitors as well as replication of existing islet beta cells are unravelled.

Vitamin C supplementation in pregnancy

BACKGROUND

Vitamin C supplementation may help reduce the risk of pregnancy complications like pre-eclampsia, intrauterine growth restriction and maternal anaemia. There is a need to evaluate the efficacy and safety of vitamin C supplementation in pregnancy.

OBJECTIVES

To evaluate the effects of vitamin C supplementation, alone or in combination with other separate supplements, on pregnancy outcomes, adverse events, side-effects and use of health resources.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (23 June 2004), Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 2, 2004), MEDLINE, Current Contents and EMBASE.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials evaluating vitamin C supplementation in pregnant women. Interventions using a multivitamin supplement containing vitamin C or where the primary supplement was iron were excluded.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trials for inclusion, extracted data and assessed trial quality.

MAIN RESULTS

Five trials, involving 766 women, are included in this review. No difference was seen between women supplemented with vitamin C alone or combined with other supplements compared with placebo for the risk of stillbirth (relative risk (RR) 0.87, 95% confidence intervals (CI) 0.41 to 1.87, three trials, 539 women), perinatal death (RR 1.16, 95% CI 0.61 to 2.18, two trials, 238 women), birthweight (weighted mean difference (WMD) -139.00 g, 95% CI -517.68 to 239.68, one trial, 100 women) or intrauterine growth restriction (RR 0.72, 95% CI 0.49 to 1.04, two trials, 383 women). Women supplemented with vitamin C alone or combined with other supplements were at increased risk of giving birth preterm (RR 1.38, 95% CI 1.04 to 1.82, three trials, 583 women). Significant heterogeneity was found for neonatal death and pre-eclampsia. No difference was seen between women supplemented with vitamin C combined with other supplements for the risk of neonatal death (RR 1.73, 95% CI 0.25 to 12.12, two trials, 221 women), using a random-effects model. For pre-eclampsia, women supplemented with vitamin C combined with other supplements were at decreased risk when using a fixed-effect model (RR 0.47, 95% CI 0.30 to 0.75, four trials, 710 women); however, this difference could not be demonstrated when using a random-effects model (RR 0.52, 95% CI 0.23 to 1.20, four trials, 710 women).

AUTHORS' CONCLUSIONS

The data are too few to say if vitamin C supplementation, alone or combined with other supplements, is beneficial during pregnancy. Preterm birth may have been increased with vitamin C supplementation.

Support during pregnancy for women at increased risk of low birthweight babies

BACKGROUND

Studies consistently show a relationship between social disadvantage and low birthweight. Many countries have programs offering special assistance to women thought to be at risk for giving birth to a low birthweight infant. These programs may include advice and counselling (about nutrition, rest, stress management, alcohol and recreational drug use), tangible assistance (eg transportation to clinic appointments, help with household responsibilities), and emotional support. The programs may be delivered by multidisciplinary teams of health professionals, by specially trained lay workers, or by a combination of lay and professional workers.

OBJECTIVES

The objective of this review was to assess the effects of programs offering additional social support for pregnant women who are believed to be at risk for giving birth to preterm or low birthweight babies.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group trials register (30 January 2003).

SELECTION CRITERIA

Randomized trials of additional support during at-risk pregnancy by either a professional (social worker, midwife, or nurse) or specially trained lay person, compared to routine care. Additional support was defined as some form of emotional support (eg counselling, reassurance, sympathetic listening) and information/advice, either in home visits or during clinic appointments, and could include tangible assistance (eg transportation to clinic appointments, assistance with the care of other children at home).

DATA COLLECTION AND ANALYSIS

Reviewers independently assessed trial quality and extracted data. Double data entry was performed. Study authors were contacted to request additional information.

MAIN RESULTS

Sixteen trials involving 13,651 women were included. The trials were generally of good to excellent quality, although 3 used an allocation method likely to introduce bias. Programs offering additional social support for at-risk pregnant women were not associated with improvements in any perinatal outcomes, but there was a reduction in the likelihood of caesarean birth and an increased likelihood of elective termination of pregnancy. Some improvements in immediate maternal psychosocial outcomes were found in individual trials.

REVIEWER'S CONCLUSIONS

Pregnant women need the support of caring family members, friends, and health professionals. While programs which offer additional support during pregnancy are unlikely to prevent the pregnancy from resulting in a low birthweight or preterm baby, they may be helpful in reducing the likelihood of caesarean birth.