Micronutrients in Multiple Pregnancies-The Knowns and Unknowns: A Systematic Review

Maternal Circulating Vitamin D Level, Targeted Supplementation, and Perinatal Outcomes in Twin Pregnancy

BACKGROUND

Vitamin D deficiency is associated with several obstetric complications in singleton pregnancy. The aim of this study was to assess whether vitamin D levels affect the outcomes of twin pregnancy and if targeted supplementation can improve perinatal outcomes.

METHODS

The serum vitamin D levels of 143 women with twin pregnancies were measured during their first trimester. Those with insufficient (10-30 ng/mL; IL group) or severely deficient (<10 ng/mL, DL group) vitamin D levels were supplemented. In the third trimester, vitamin D levels were reassessed. Perinatal outcomes of the IL and DL groups were compared with those of patients with sufficient levels (>30 ng/mL, SL group) since the beginning of pregnancy.

RESULTS

Women in the IL and DL groups had a higher incidence of hypertensive disorders of pregnancy (HDP) compared to the SL group (24.8% and 27.8% vs. 12.5%, p = 0.045): OR = 1.58 for the IL group and 1.94 for the DL group compared to the SL group. In patients whose vitamin D levels were restored after supplementation, HDP incidence was lower than in patients who remained in the IL or DL groups (23.4% vs. 27.3%) but higher than those who were always in the SL group (12.5%).

CONCLUSIONS

Insufficient or severely deficient levels of vitamin D in the first trimester are associated with an increased risk of HDP in twin pregnancy. The beneficial effect of targeted vitamin D supplementation in reducing HDP seems limited.

Nutritional Intake in Dichorionic Twin Pregnancies: A Descriptive Analysis of a Multisite United States Cohort

INTRODUCTION

Twin gestations have greater nutritional demands than singleton gestations, yet dietary intakes of women with twin gestations have not been well described.

METHODS

In a prospective, multi-site US study of 148 women with dichorionic twin gestations (2012-2013), we examined longitudinal changes in diet across pregnancy. Women completed a food frequency questionnaire during each trimester of pregnancy. We examined changes in means of total energy and energy-adjusted dietary components using linear mixed effects models.

RESULTS

Mean energy intake (95% CI) across the three trimesters was 2010 kcal/day (1846, 2175), 2177 kcal/day (2005, 2349), 2253 kcal/day (2056, 2450), respectively (P = 0.01), whereas the Healthy Eating Index-2010 was 63.9 (62.1, 65.6), 64.5 (62.6, 66.3), 63.2 (61.1, 65.3), respectively (P = 0.53).

DISCUSSION

Women with twin gestations moderately increased total energy as pregnancy progressed, though dietary composition and quality remained unchanged. These findings highlight aspects of nutritional intake that may need to be improved among women carrying twins.

Determination of vitamin D status in singleton and twin gestations using CLIA and LC-MS/MS

Objective

Vitamin D plays an important role during pregnancy. The aim was to compare vitamin D status in a group of singleton (SP) and twin pregnancies (TP) using two diagnostic methods: chemiluminescence immunoassay (CLIA) and liquid chromatography with tandem mass spectrometry (LC-MS/MS).

Design

This is a cross-sectional study.

Methods

The study was conducted in the population of SP and TP at the gestational age above 20 + 0 at the Bielanski Hospital in Warsaw, Poland, between October 2020 and January 2023. All patients had their venous blood samples collected and were given an original survey containing questions on demography and vitamin D supplementation.

Results

The study group included 53 Caucasian women with SP and 78 with TP aged from 21 to 47. Considering LC-MS/MS, patients with TP had lower concentrations of 25-hydroxyvitamin D (25(OH)D) than patients with SP. However, no significant difference was observed in the frequency of the occurrence of vitamin D deficiency (25(OH)D < 30 ng/mL). In both groups, the levels obtained with CLIA were significantly lower than in case of LC-MS/MS, however, strongly correlated. The intermethod agreement accounted for 52.4% and the Cohen's kappa coefficient was 0.142.

Conclusions

The concentration of 25(OH)D in pregnant women depends on the type of gestation (SP/TP) and on the diagnostic methods used (CLIA/LC-MS/MS). Based on LC-MS/MS, the incidence of vitamin D deficiency was low in our group and no differences occurred in its frequency between SP and TP. The intermethod agreement between CLIA and LC-MS/MS on the detection of vitamin D deficiency was low.

Significance statement

This is the first study to compare the concentration of 25(OH)D levels between SP and TP using two methods: CLIA and the gold standard - LC-MS/MS. Based on LC-MS/MS, a low incidence of vitamin D deficiency was observed in our group, in which the vast majority of patients took cholecalciferol supplements. Moreover, there were no differences in its frequency between SP and TP. However, the 25(OH)D level was significantly lower in TP. The intermethod agreement between CLIA and LC-MS/MS on the detection of vitamin D deficiency was low, which is associated with substantial clinical implications.

Twin charts should be the standard reference to assess growth in twin pregnancy

PURPOSE OF REVIEW

Twin pregnancies are characterized by slower growth velocity compared with singletons, especially during the third trimester and, therefore, tend to be smaller than singletons. Growth surveillance is instrumental in the identification of twin pregnancies at risk of adverse outcomes. Whether the phenomenon of slow growth is an adaptive physiological response or represents pathological growth lag, is controversial. In this review, we focus on the evidence related to the types of growth charts employed for twin pregnancies.

RECENT FINDINGS

Consistent evidence has emerged over the past few years from large independent cohorts in different countries suggesting that twin-specific standards perform better in identifying growth-restricted twin pregnancies at risk of adverse perinatal outcomes, without resulting in an increase in interventions or iatrogenic prematurity.

SUMMARY

The current evidence supports the use of twin-specific reference charts. Concerted efforts should be made to derive prospective evidence from large multicentre studies on various aspects of the implementation of twin-specific standards.

Predisposing factors of non-syndromic cleft lip and cleft palate in the northern Thai population: A 10-year retrospective case-control study

The most common congenital anomaly is orofacial cleft, which is categorized into two main types: cleft lip with or without cleft palate (CL/P) and cleft palate only (CPO). One of the most accepted etiologies is multifactorial (gene-environment). This study aimed to identify the amendable risk factors of an orofacial cleft in Northern Thailand. A retrospective case-control study in Maharaj Nakorn Chiang Mai Hospital was conducted from 2011 to 2020. One hundred and seventeen cases of CL/P and CPO were included. Forty-nine normal children were enrolled in a time-matched control group. Exploratory survey data on maternal exposures were collected. Multivariate logistic regression was used to estimate the adjusted association between maternal exposures and CL/P, and CPO occurrence. Multivariate analysis identified three predisposing factors that increased the risk of CL/P and CPO. The first factor was caffeine consumption with a total amount of 560 mg/week (adjusted OR: 7.59; 95% CI: 2.48-23.23; p < 0.001). The second factor was any smoker or passive smoking (adjusted OR: 8.47; 95% CI: 1.63-43.92; p = 0.011). The third factor was a low socioeconomic status (income of lower than 270 USD/month; adjusted OR: 4.05; 95% CI: 1.07-15.27; p = 0.039). From the 10-year study in Northern Thailand: caffeine consumption, exposure to cigarette smoke, and low socioeconomic status were identified as associated negative factors for orofacial clefts. We propose that preconceptional counseling for risk reduction should be emphasized in reducing the mother's exposure to these factors. Future investigations in large multicenter populations are suggested.

Fatty Acid Composition of a Maternal Diet and Erythrocyte Phospholipid Status in Latvian Pregnant Women

BACKGROUND AND OBJECTIVES

Dietary fats are essential for maternal and fetal health. Fatty acids (FAs) in erythrocytes characterize the FA profile, which is influenced by diet and other factors. The aim of this study was to evaluate the association between the main FAs in erythrocyte membrane phospholipids and their influencing factors-dietary fat and supplement intake and lifestyle factors-in Latvian pregnant women.

MATERIALS AND METHODS

This cross-sectional study included 236 pregnant and postpartum women. The data were collected from medical documentation, a food frequency questionnaire, and a questionnaire on demographic, lifestyle, health status, and nutritional habits in outpatient clinics and maternity departments. FAs in erythrocyte membrane phospholipids were determined using gas chromatography.

RESULTS

Correlations were found between dietary SFAs and erythrocyte SFAs (r = -0.140, p = 0.032) and PUFAs (r = 0.167, p = 0.01) and between dietary PUFAs and erythrocyte MUFAs (r = -0.143, p = 0.028). Dietary SFAs, MUFAs, and PUFAs positively correlated with the studied n-3 and n-6 FAs in erythrocytes. Vitamin D correlated positively with MUFA and negatively with total PUFA and AA in erythrocytes. There was a negative correlation between dietary vitamin A and linoleic acid in erythrocytes. Physical activity negatively correlated with erythrocyte MUFAs and positively with erythrocyte PUFAs. Alcohol consumption positively correlated with erythrocyte SFAs and negatively with erythrocyte PUFAs.

CONCLUSIONS

There are indications that some dietary FAs may be correlated with erythrocyte FAs. Possible influencing factors for this association are alcohol, physical activity, vitamin D, and vitamin A.

Plasma Retinol Concentrations and Dietary Intakes of Mother-Infant Sets in Singleton versus Twin Pregnancy

Vitamin A (retinol) is essential for normal fetal development, but the recommendation for maternal dietary intake (Retinol Activity Equivalent, RAE) does not differ for singleton vs. twin pregnancy, despite the limited evaluation of retinol status. Therefore, this study aimed to evaluate plasma retinol concentrations and deficiency status in mother-infant sets from singleton vs. twin pregnancies as well as maternal RAE intake. A total of 21 mother-infant sets were included (14 singleton, 7 twin). The HPLC and LC-MS/HS evaluated the plasma retinol concentration, and data were analyzed using the Mann-Whitney U test. Plasma retinol was significantly lower in twin vs. singleton pregnancies in both maternal (192.2 vs. 312.1 vs. mcg/L, p = 0.002) and umbilical cord (UC) samples (102.5 vs. 154.4 vs. mcg/L, p = 0.002). The prevalence of serum-defined vitamin A deficiency (VAD) <200.6 mcg/L was higher in twins vs. singletons for both maternal (57% vs. 7%, p = 0.031) and UC samples (100% vs. 0%, p < 0.001), despite a similar RAE intake (2178 vs. 1862 mcg/day, p = 0.603). Twin pregnancies demonstrated a higher likelihood of vitamin A deficiency in mothers, with an odds ratio of 17.3 (95% CI: 1.4 to 216.6). This study suggests twin pregnancy may be associated with VAD deficiency. Further research is needed to determine optimal maternal dietary recommendations during twin gestation.

Association of maternity formula supplementation during pregnancy with small for gestational age birth in Chinese newborns

OBJECTIVES

This study aimed to explore the association between maternity formula supplementation and small for gestational age (SGA) status in Chinese newborns.

METHODS

Data were from a population-based cross-sectional survey conducted in Shaanxi, Northwest China between August and December 2013. A total of 27 780 women pregnant with singletons and 356 with twins were included in this survey. Information on use of maternity formulas fortified with vitamins, folic acid, pantothenic acid, calcium, iron, zinc, and docosahexaenoic acid (DHA) was collected. SGA was defined as birthweight <10th percentile of fetal growth. Generalized linear models and estimating equation models were used to estimate crude odds ratios (ORs) or adjusted ORs with 95% confidence intervals (CIs) for SGA.

RESULTS

The rate of maternity formula supplementation during the entire pregnancy was 13.0% in the overall population. There was no significant association between maternal formula supplementation during pregnancy and the risk of total SGA birth (OR: 1.00; 95% CI, 0.90-1.11; P = 0.950). However, maternity formula supplementation during pregnancy was related to a lower risk of SGA for twins (OR: 0.49; 95% CI, 0.31-0.80; P = 0.004), twin A (OR: 0.50; 95% CI, 0.25-0.98; P = 0.045), and twin B (OR: 0.48; 95% CI, 0.25-0.95; P = 0.034). Furthermore, maternity formula supplementation during the first trimester was inversely associated with the risk of SGA birth of twins (OR: 0.32; 95% CI, 0.15-0.65; P = 0.002).

CONCLUSIONS

No significant association was observed between maternity formula supplementation and total SGA birth. However, women supplemented with maternal formula during pregnancy, especially during the first trimester, may have a reduced risk of SGA birth of twins.

Electrically-driven handling of gametes and embryos: taking a step towards the future of ARTs

Electrical stimulation of gametes and embryos and on-chip manipulation of microdroplets of culture medium serve as promising tools for assisted reproductive technologies (ARTs). Thus far, dielectrophoresis (DEP), electrorotation (ER) and electrowetting on dielectric (EWOD) proved compatible with most laboratory procedures offered by ARTs. Positioning, entrapment and selection of reproductive cells can be achieved with DEP and ER, while EWOD provides the dynamic microenvironment of a developing embryo to better mimic the functions of the oviduct. Furthermore, these techniques are applicable for the assessment of the developmental competence of a mammalian embryo in vitro. Such research paves the way towards the amelioration and full automation of the assisted reproduction methods. This article aims to provide a summary on the recent developments regarding electrically stimulated lab-on-chip devices and their application for the manipulation of gametes and embryos in vitro.

Review of Dietary Recommendations for Twin Pregnancy: Does Nutrition Science Keep Up with the Growing Incidence of Multiple Gestations?

Recommendations for nutrition and the use of dietary supplements for pregnant women are updated on regular basis but it remains to be seen to what extent they may be applicable in twin pregnancies. The aim of this narrative review is to present the current state of knowledge about the energy and nutrient demand in twin pregnancy. There is general consensus in literature that the energy demand is higher than in a singleton pregnancy, but there is a lack of position statements from scientific societies on specific energy intake that is required. In turn, recommended maternal weight gain, which favors the normal weight of the neonate, has been determined. There is even a larger knowledge gap when it comes to vitamins and minerals, the body stores of which are theoretically used up faster. The greatest number of studies so far focused on vitamin D, and most of them concluded that its concentration in maternal blood is lower in twin as compared to singleton pregnancy. Few randomized studies focus on iron supplementation and there are no other studies that would assess dietary interventions. In light of a growing incidence of multiple pregnancies, more studies are necessary to establish the nutritional demands of the mother and the course of action for adequate supplementation.

Maternal thyroid function in multiple pregnancies - a systematic review

BACKGROUND

The function of the thyroid gland during pregnancy undergoes physiological changes to ensure the proper amount of thyroid hormones for both the pregnant woman and the fetus. Multiple pregnancies (MP) are characterized by specific differences compared to single pregnancies, e.g., higher concentrations of human chorionic gonadotropin, which also affect thyroid function. The aim was to collect available knowledge on maternal thyroid function in MP.

METHODS

We have systematically searched three databases: the PubMed/MEDLINE, Scopus and the Cochrane Library. The last search was run on the 4th of August 2022. We included full-text original observational and experimental studies written in English. Case reports, editorials, letters, conference abstracts, reviews and meta-analyses were excluded. No time criterion was established. Studies were considered eligible if at least one maternal thyroid function test was performed and reported. Studies on MP with a co-existing mole were excluded. The risk of bias was assessed with the use of the AXIS tool. The qualitative synthesis of evidence was applied.

RESULTS

The search strategy resulted in the identification of 821 manuscripts. After removing duplicates, we screened the titles and abstracts of 552 articles, out of which 57 were selected for full-text analysis. Finally, 12 articles were included in the review. They were conducted in 6 different countries and published between the years 1997 and 2022. The number of examined women with MP ranged from 9 to 1 626.

DISCUSSION AND CONCLUSIONS

Thyroid function differs between women with MP and SP. Scarce data are available on the topic, but MPs are most likely characterized by higher HCG levels, which influences thyroid-stimulating hormone and free thyroid hormone levels. These differences are mainly expressed in the 1st trimester of pregnancy. Separate population-based reference ranges are needed to correctly diagnose thyroid diseases in MP and to avoid unnecessary treatment. Further research is needed to fill the knowledge gaps.

Is serum zinc status related to gestational diabetes mellitus? A meta-analysis

Gestational diabetes mellitus (GDM) is a common medical disorder that begins during pregnancy. The present work aimed to investigate the relationship of maternal or foetal circulatory zinc levels with GDM. Related studies were retrieved against the PubMed/Medline, Web of Science, Scopus databases till July 2020. The overall effects were expressed as standard mean difference (SMD). Furthermore, the random effects model was used to assess the summarised risk ratios (SRRs) to determine the relationship between zinc and the risk of GDM. A total of 15 articles involving were retrieved for meta‐analysis; in the meantime, 4955 subjects including 1549 GDM cases were enrolled for quantitative analysis. Compared with normal control, GDM cases had decreased circulating zinc level on the whole, but the difference was not statistically significant (SMD = −0.40, 95%CI: −0.80 to −0.00, P = 0.05). Interestingly, upon subgroup analysis stratified by serum zinc content but not plasma zinc concentration, there was significant difference in zinc content between GDM cases and normal controls (SMD = −0.56; 95%CI: −1.07 to −0.04, P = 0.03). Meanwhile, subgroup analysis also revealed similar tendency among the Asians and during the 2nd trimester, but not among the Caucasians or during the 1st or 3rd trimester. Data extracted from four studies that compared pregnant women with GDM in the high level of zinc and GDM in the low level of zinc yielded an SRR of 0.929 (95%CI: 0.905–0.954). According to existing evidence, the serum zinc content decreases among GDM cases compared with subjects with no abnormality in glucose tolerance, in particular among the Asians and during the second trimester. Nonetheless, more well designed prospective study should be carried out for understanding the dynamic relationship of zinc level with the incidence of GDM.