Plasma concentrations of unconjugated estrone, estradiol-17beta and estriol, and HCS throughout pregnancy in diabetics and gestational diabetics

Human Placental Lactogen in Relation to Maternal Metabolic Health and Fetal Outcomes: A Systematic Review and Meta-Analysis

Human placental lactogen (hPL) is a placental hormone which appears to have key metabolic functions in pregnancy. Preclinical studies have putatively linked hPL to maternal and fetal outcomes, yet-despite human observational data spanning several decades-evidence on the role and importance of this hormone remains disparate and conflicting. We aimed to explore (via systematic review and meta-analysis) the relationship between hPL levels, maternal pre-existing and gestational metabolic conditions, and fetal growth. MEDLINE via OVID, CINAHL plus, and Embase were searched from inception through 9 May 2022. Eligible studies included women who were pregnant or up to 12 months post-partum, and reported at least one endogenous maternal serum hPL level during pregnancy in relation to pre-specified metabolic outcomes. Two independent reviewers extracted data. Meta-analysis was conducted where possible; for other outcomes narrative synthesis was performed. 35 studies met eligibility criteria. No relationship was noted between hPL and gestational diabetes status. In type 1 diabetes mellitus, hPL levels appeared lower in early pregnancy (possibly reflecting delayed placental development) and higher in late pregnancy (possibly reflecting increased placental mass). Limited data were found in other pre-existing metabolic conditions. Levels of hPL appear to be positively related to placental mass and infant birthweight in pregnancies affected by maternal diabetes. The relationship between hPL, a purported pregnancy metabolic hormone, and maternal metabolism in human pregnancy is complex and remains unclear. This antenatal biomarker may offer value, but future studies in well-defined contemporary populations are required.

GPER1 is required to protect fetal health from maternal inflammation

Type I interferon (IFN) signaling in fetal tissues causes developmental abnormalities and fetal demise. Although pathogens that infect fetal tissues can induce birth defects through the local production of type I IFN, it remains unknown why systemic IFN generated during maternal infections only rarely causes fetal developmental defects. Here, we report that activation of the guanine nucleotide-binding protein-coupled estrogen receptor 1 (GPER1) during pregnancy is both necessary and sufficient to suppress IFN signaling and does so disproportionately in reproductive and fetal tissues. Inactivation of GPER1 in mice halted fetal development and promoted fetal demise, but only in the context of maternal inflammation. Thus, GPER1 is a central regulator of IFN signaling during pregnancy that allows dynamic antiviral responses in maternal tissues while also preserving fetal health.

Evolution of steroids during pregnancy: Maternal, placental and fetal synthesis

Progesterone, estrogens, androgens and glucocorticoids are involved in pregnancy from implantation to parturition. Their biosynthesis and their metabolism result from complex pathways involving the fetus, the placenta and the mother. The absence of expression of some steroïdogenic enzymes as CYP17 in placenta and in adrenal fetal zone and the better determination of the onset and variation of others especially HSD3B2 during the pregnancy explain the production of the steroid hormones. Moreover the consequences of some disorders of steroidogenesis (especially aromatase, POR, CYP11A1 and 21-hydroxylase deficiencies) in fetus and mother during the pregnancy have permit to elucidate these complex pathways. This better knowledge of steroid hormones production associated with their dosages in maternal plasma/urine or amniotic fluid using new specific assays as LC-MS MS could facilitate the follow-up of normal and pathological pregnancies. Moreover, these advances should be a basis to evaluate the impact of multiple pathologies of the pregnancy and pharmacologic and xenobiotic consequences on their metabolism.

Metabolic control and serum hormone levels in relation to retinopathy in diabetic pregnancy

The occurrence and progression of retinopathy were related to the mean blood glucose levels and the serum concentrations of prolactin, human placental lactogen, oestradiol and progesterone in 57 pregnant insulin-dependent diabetic patients. Fifteen patients had frank retinopathy, of whom eight showed a marked increase in retinopathy. The initial blood glucose levels were significantly higher in patients whose retinopathy progressed, whereas during the second and third trimester similar blood glucose levels were achieved in all groups. Serum concentrations of progesterone and human placental lactogen were significantly increased in diabetic patients during the last trimester when compared with those in normal pregnancies, and during the second trimester, patients with retinopathy showed significantly higher concentrations than those without, but no significant difference was found in oestradiol values. The eight patients with progressive retinopathy showed progesterone, human placental lactogen and oestradiol levels at or above the upper limit of the normal range. Throughout gestation, serum prolactin concentrations were significantly lower in diabetic patients than in healthy subjects. No correlation was found between serum prolactin values and the occurrence of retinopathy.