Does fish oil prevent preterm birth?

Effects of Maternal Nutritional Supplements and Dietary Interventions on Placental Complications: An Umbrella Review, Meta-Analysis and Evidence Map

The placenta is a vital, multi-functional organ that acts as an interface between maternal and fetal circulation during pregnancy. Nutritional deficiencies during pregnancy alter placental development and function, leading to adverse pregnancy outcomes, such as pre-eclampsia, infants with small for gestational age and low birthweight, preterm birth, stillbirths and maternal mortality. Maternal nutritional supplementation may help to mitigate the risks, but the evidence base is difficult to navigate. The primary purpose of this umbrella review is to map the evidence on the effects of maternal nutritional supplements and dietary interventions on pregnancy outcomes related to placental disorders and maternal mortality. A systematic search was performed on seven electronic databases, the PROSPERO register and references lists of identified papers. The results were screened in a three-stage process based on title, abstract and full-text by two independent reviewers. Randomized controlled trial meta-analyses on the efficacy of maternal nutritional supplements or dietary interventions were included. There were 91 meta-analyses included, covering 23 types of supplements and three types of dietary interventions. We found evidence that supports supplementary vitamin D and/or calcium, omega-3, multiple micronutrients, lipid-based nutrients, and balanced protein energy in reducing the risks of adverse maternal and fetal health outcomes. However, these findings are limited by poor quality of evidence. Nutrient combinations show promise and support a paradigm shift to maternal dietary balance, rather than single micronutrient deficiencies, to improve maternal and fetal health. The review is registered at PROSPERO (CRD42020160887).

Unexpected clinical sequelae of Gitelman syndrome: hypertension in adulthood is common and females have higher potassium requirements

Background

Gitelman syndrome (GS) is a rare inherited disorder caused by mutations in SLC12A3, encoding the thiazide-sensitive transporter NCCT (sodium chloride co-transporter) in the distal tubule. It is characterized by renal potassium (K) and magnesium (Mg) wasting, relative hypotension and hypocalciuria. However, there is phenotypic variability and long-term studies are scarce.

Methods

We retrospectively assessed clinical and genetic characteristics, and electrolyte requirements, in a cohort of 36 patients with genetically proven GS.

Results

The 21 males and 15 females were of median age 39.5 years, range 17–66 years. Six were diagnosed in childhood. Among the 72 mutant alleles, 41 different sequence alterations were identified, of which 13 were previously unreported. Surprisingly, 44% (n = 16) of the cohort has developed hypertension (13 males, 3 females, P = 0.019; median age 53 versus 57 years, P = 0.95). One was already hypertensive by age 23 years. Currently normotensive patients were significantly younger: median 37 versus 55 years (P = 0.005). Hypertensive patients were more likely to harbour mutations in the C-terminal half of the NCCT protein (P = 0.016). Females required more K (median 128 versus 72 mmol/day; P = 0.01) but not Mg. Those with exon 26 and/or at least one destructive mutation had higher K requirements than those with neither: 108 versus 72 mmol (P = 0.016) and a tendency towards higher Mg needs: 30 versus 7.4 mmol (P = 0.07).

Conclusions

Our findings suggest that the development of secondary hypertension may be an expected feature of the ageing GS population despite the obligate salt wasting that characterizes the disorder. We hypothesize that this may be related to chronic secondary hyperaldosteronism. The apparently more severe phenotype in women may be related to the effects of female sex hormones on expression or function of NCCT.