Increase in maternal placental growth hormone during pregnancy and disappearance during parturition in normal and growth hormone-deficient pregnancies

Serum BAFF (B-cell activating factor) and APRIL (a proliferation-inducing ligand) levels in the first trimester may predict the future development of gestational diabetes mellitus

BACKGROUND

Gestational diabetes mellitus (GDM) is a prevalent condition with an unclear pathogenesis. B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are potential key players in GDM.

PARTICIPANTS, MATERIALS, AND METHODS

In a longitudinal observational study, we monitored women from the first trimester through 24-28 weeks of gestation, focusing on the development of GDM. Serum levels of BAFF and APRIL, as well as their mRNA expression, were evaluated in both the first and third trimesters. Furthermore, we assessed cytokines, adipokines, and placental hormones in the serum.

RESULTS

In the first trimester, participants who later developed GDM exhibited elevated serum BAFF and reduced serum APRIL levels, although the mRNA expression of these molecules was similar to controls. Serum BAFF exhibited significant positive correlations with metabolic markers and placental hormones. Conversely, serum APRIL was negatively correlated with insulin resistance and inflammatory markers but positively correlated with adiponectin. In the early third trimester, GDM participants continued to display higher serum BAFF levels and lower serum APRIL levels than controls. There was no significant difference in mRNA expression of BAFF between GDM and control groups. Conversely, APRIL mRNA expression was significantly lower in the GDM group. The predictive potential of first-trimester BAFF and APRIL levels for future GDM development was explored, with both molecules demonstrating strong predictive capability.

DISCUSSION AND CONCLUSION

This study suggests that elevated serum BAFF and reduced serum APRIL levels during pregnancy may be associated with the development of GDM. These biomarkers can serve as potential early predictors for GDM.

Simultaneous quantification of the 22-kDa isoforms of human growth hormone 1 and 2 in human plasma by multiplexed immunocapture and LC-MS/MS

An LC-MS/MS method is presented for the simultaneous quantification of two structurally closely related protein biomarker isoforms, the 22-kDa isoforms of human growth hormone 1 and human growth hormone 2, in human plasma. It is based on multiplexed immunocapture using two monoclonal antibodies immobilized on magnetic beads, tryptic digestion and quantification of two specific signature peptides plus an additional peptide for estimation of total growth hormone related concentrations. A full validation according to international guidelines was performed across the clinically relevant concentration ranges of 0.5 to 50 ng/mL for growth hormone 1, and 2 to 50 ng/mL for growth hormone 2 and demonstrated satisfactory method performance in terms of accuracy, precision, stability and absence of interference. The method's applicability for routine analysis and its ability to effectively distinguish between GH1 and GH2 was demonstrated by the analysis of plasma samples from pregnant individuals to study the changes in growth hormone levels during pregnancy.

Live Births in Women over 40 Years of Age Correlate with Obesity Rates

AIMS

This cross-sectional study aimed to analyze the relationship between live birth and the prevalence of obesity in Chinese women over 40 years of age.

METHODS

From April to November 2011, the Endocrinology Branch of the Chinese Medical Association conducted the REACTION project, a national, multicenter, cross-sectional study of Chinese adults aged 40 years and older. Demographic and medical data were collected through validated questionnaires and equipment. Anthropometric indicators, blood pressure, and biochemical data were measured by professional medical personnel. Data were analyzed using descriptive statistics and logistic analysis. Multivariate regression models were used to analyze obesity-related risk factors.

RESULTS

The prevalence of obesity among women increased gradually from 3.8% to 6.0% with an increasing number of live births. Women with two live births had the highest prevalence of overweight at 34.3%. Overall, the obesity and overweight rates were slightly higher in premenopausal women than in postmenopausal women. Univariate regression analysis showed that the risk of obesity in women increased with an increasing number of live births. In addition, multivariate regression analysis showed that the risk of obesity increased with an increasing number of live births in women with systolic blood pressure (SBP) < 121 mmHg or current smoking (P < 0.05).

CONCLUSION

The risk of obesity increases with the number of live births in Chinese women over 40 years of age with SBP < 121 mmHg or current smoking. Our findings may facilitate the development of interventions to prevent obesity in this population.

Racial differences in the associations between adiposity, placental growth hormone and inflammatory cytokines in pregnant women

BACKGROUND

The prevalence of obesity among women of child-bearing age has contributed to an increased risk of pregnancy complications with a disproportional impact on women of lower socioeconomic status and among certain racial groups. In particular, socio-demographic and historical factors have resulted in higher rates of premature births and small-for-gestational age infants among Black women, which may be associated with placental function during pregnancy. The current study investigated the influence of maternal pre-pregnancy adiposity and race on the associations between inflammatory proteins, placental growth hormone (PGH), and infant birthweight. This information was collected for a subsample of 109 participants (Black, n = 39 vs. White, n = 70) from the Brain and Early Experiences (BEE) study.

METHODS

Serum samples were acquired late in the second trimester to assess PGH levels, C-reactive protein (CRP), interleukin 6 (IL-6), interleukin 8 (IL-8), and interleukin-1 receptor antagonist (IL-1Ra). Participant questionnaire responses provided information on pre-pregnancy BMI, health, race, educational attainment, and infant birthweight. Bivariate correlations and multiple linear regression models were utilized to evaluate associations by race between preconception adiposity, inflammatory markers and PGH.

RESULTS

After controlling for covariates including maternal age and education, gestational age, and fetal sex, regression models indicated that pre-pregnancy BMI was negatively associated with PGH (β=-0.42, p<0.05) and IL-8 was positively associated with PGH (β=0.35, p<0.05) among the Black mothers only; neither were significantly associated with PGH in the White mothers. When extending models to birth outcomes, BMI was positively associated with birthweight corrected for gestational age (BWz) (β=0.24, p<0.05) and educational attainment was negatively associated with BWz (β=0.28, p<0.05) for infants of White women. In contrast, neither variable was predictive of BWz for infants of Black mothers.

CONCLUSION

Future work is needed to investigate racial differences in the association between adiposity and placental functioning, which are likely to contribute to differential effects on pregnancy outcomes and fetal growth.

Normal-high IGF-1 level improves pregnancy rate after ovarian stimulation in women treated with growth hormone replacement therapy

Objective

Growth hormone (GH) and insulin-like growth factors (IGFs) are not mandatory for reproductive life, but data suggest their synergistic action with follicle-stimulating hormone throughout ovarian folliculogenesis. We aimed to evaluate the association of IGF-1 level on clinical pregnancy rate after ovarian stimulation, with or without intrauterine insemination, in women with GH deficiency (GHD) treated with GH replacement therapy (GHRT) at conception.

Design and methods

Data from 19 women with both GHD and hypogonadotropic hypogonadism referred to our reproductive medicine department were retrospectively collected. IGF-1 levels were assessed in a single laboratory, and values were expressed in s.d. from the mean.

Results

Amongst the seven patients receiving GHRT during ovarian stimulation, higher IGF-1 levels were significantly associated with clinical pregnancy (+0.4 s.d. vs-1.6 s.d., P = 0.03). Amongst the 24 pregnancies obtained by the 19 infertile patients, pregnancy loss was less frequent with the addition of GHRT than without (1 miscarriage out of 8 total pregnancies vs 4 miscarriages out of 16 total pregnancies).

Conclusions

This is the first study evaluating the association of IGF-1 level on clinical pregnancy rate in GH-treated women at conception. When taking care of female infertility due to hypogonadotropic hypogonadism, practitioners should enquire about the associated GHD and IGF-1 levels. To ensure higher clinical pregnancy chances, practitioners should aim for IGF-1 values at conception, ranging from 0 s.d. to +2 s.d., and, if necessary, could discuss initiation or increase GH treatment. Prospective studies should help strengthen our results.

Selective quantification of the 22-kDa isoform of human growth hormone 1 in serum and plasma by immunocapture and LC-MS/MS

The human growth hormone GH1 (22 kDa) is a commonly measured biomarker for diagnosis and during treatment of growth disorders, but its quantification by ligand binding assays may be compromised by the occurrence of a number of isoforms. These can interfere in the assays and lead to differences in results between laboratories and potentially even in the treatment of patients. We present an LC-MS/MS method that is able to distinguish the major growth hormone isoform (GH1, 22 kDa) from other isoforms and quantify it without any interference across the clinically relevant concentration range of 0.5 to 50 ng/mL. Analysis involves purification of a 100-µL serum sample by immunocapture using an anti-GH-directed antibody, tryptic digestion, and LC-MS/MS quantification of an isoform-specific signature peptide for GH1 (22 kDa). A tryptic peptide occurring in all GH isoforms is monitored in the same 16-min analytical run as a read-out for total GH. Stable-isotope-labeled forms of these two peptides are included as internal standards. Full validation of the method according to recent guidelines, against a recombinant form of the analyte in rat plasma calibrators, demonstrated intra-assay and inter-assay imprecision below 6% across the calibration range for both signature peptides and recoveries between 94 and 102%. An excellent correlation was found between nominal and measured concentrations of the WHO reference standard for GH1 (22 kDa). Addition of up to 1000 ng/mL biotin or the presence of a 100-fold excess of GH binding protein did not affect the measurement. Equivalent method performance was found for analysis of GH in serum, EDTA, and heparin plasma. Analyte stability was demonstrated during all normal sample storage conditions. Comparison with the IDS-iSYS GH immunoassay showed a good correlation with the LC-MS/MS method for the isoform-specific signature peptide, but a significant positive bias was observed for the LC-MS/MS results of the peptide representing total GH. This seems to confirm the actual occurrence of other GH isoforms in serum. Finally, in serum from pregnant individuals, no quantifiable GH1 (22 kDa) was found, but relatively high concentrations of total GH.

Hypopituitarism and pregnancy: clinical characteristics, management and pregnancy outcome

PURPOSE

To describe the clinical characteristics, management and pregnancy outcome of women with prepregnancy hypopituitarism (HYPO) that received care at our center.

METHODS

Retrospective study describing 12 pregnancies in women with prepregnancy HYPO (two or more pituitary hormonal deficiencies under replacement treatment) that received care during pregnancy at Hospital Santa Creu i Sant Pau. Clinical characteristics, management and pregnancy outcome were systematically collected.

RESULTS

Average patients' age was 35 years and HYPO duration at the beginning of pregnancy was 19 years. The most frequent cause of HYPO was surgical treatment of a sellar mass (8 pregnancies). Eight pregnancies were in primigravid women and 10 required assisted reproductive techniques. The hormonal deficits before pregnancy were as follows: GH in 12 women, TSH in 10, gonadotropin in 9, ACTH in 5 and ADH in 2. All deficits were under hormonal substitution except for GH deficit in 4 pregnancies. During pregnancy, 4 new deficits were diagnosed. The dosage of replacement treatment for TSH, ACTH and ADH deficits was increased and GH was stopped. Average gestational age at birth was 40 weeks, gestational weight gain was excessive in 9 women, 8 patients required induction/elective delivery and cesarean section was performed in 6. Average birthweight was 3227 g. No major complications were observed. Five women were breastfeeding at discharge.

CONCLUSIONS

In this group of women with long-standing HYPO, with careful clinical management (including treatment of new-onset hormonal deficits) pregnancy outcome was satisfactory but with a high rate of excessive gestational weight gain and cesarean section.

Pregnancy outcomes in women receiving growth hormone replacement therapy enrolled in the NordiNet® International Outcome Study (IOS) and the American Norditropin® Studies: Web-Enabled Research (ANSWER) Program

PURPOSE

Data on the safety of growth hormone (GH) replacement therapy during pregnancy are limited. We report a combined analysis of data from pregnant women treated with GH while enrolled in two non-interventional, multicenter studies: NordiNet® International Outcome Study (IOS) and the American Norditropin® Studies: Web-Enabled Research (ANSWER) Program.

METHODS

Pregnancy data were pooled from NordiNet® IOS and the ANSWER Program. Data were collected during routine clinic visits by participating physicians using a web-based system. Patients exposed to GH replacement therapy during pregnancy were included in the analysis.

RESULTS

The study population included 40 female patients with typical causes of adult GH deficiency (GHD). Overall, there were 54 pregnancies. Of these, 47 were exposed to GH between conception and delivery. In 48.9% of pregnancies exposed to GH, the dose was > 0.6 mg/day. GH was continued past conception and then stopped during the first, second, and third trimester, in 27.7%, 17.0%, and 2.1% of pregnancies, respectively. In 29.8%, GH was continued throughout pregnancy, with an unchanged dose in most cases. Of the 47 GH-exposed pregnancies, 37 (78.7%) progressed to normal delivery. There were three adverse events reported in two pregnancies.

CONCLUSION

These real-world data suggest that there were no new safety signals related to GH exposure in women with GHD during pregnancy. These results are consistent with findings from previous studies reporting data in pregnancies exposed to GH at conception or throughout pregnancy. This observational study in additional pregnancies provides further evidence that GH exposure does not adversely affect pregnancy outcome.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov NCT00960128 (date of registration: August 13, 2009) and NCT01009905 (date of registration: November 5, 2009).

Growth hormone replacement improved oocyte quality in a patient with hypopituitarism: a study of follicular fluid

BACKGROUNDː Growth hormone (GH) is known to be involved in ovarian folliculogenesis and oocyte maturation. In patients with poor ovarian response without growth hormone deficiency (GHD), adjuvant GH treatment improves in-vitro fertilization (IVF) results. Improvement of oocyte quality in IVF by GH replacement was reported in only a few patients with GHD. We report on another case with study of follicular fluid. METHODSː A 29-year-old patient with hypopituitarism was referred to our infertility center. She was undergoing hormonal replacement for hypogonadotropic hypogonadism and diabetes insipidus, and did not at first want GH replacement. Four IVF procedures were performed between 2011 and 2014. Growth hormone replacement (somatotropin 1.1mg/day) was initiated before the fourth IVF procedure and unmasked central hypothyroidism; levothyroxine (75 mg/day) was introduced. It took 10 months to reach the treatment objectives for insulin-like growth factor 1 (IGF1), free triiodothyronine (fT3) and free thyroxine (fT4). GH, IGF1 and thyroid hormones were measured in the blood and follicular fluid before and after GH and thyroid hormone replacement. Oocyte and embryo quality were also compared. RESULTSː The first 3 IVF procedures were performed without GH replacement. 62% to 100% of mature oocytes presented one or more morphologic abnormalities: diffuse cytoplasmic granularity, large perivitelline space with fragments, fragmentation of the first polar body, ovoid shape, or difficult denudation. Embryo quality was moderate to poor (grade B to D), and no pregnancy was obtained after embryo transfer. After GH replacement, hormones levels increased in follicular fluid: GH [7.68 vs. 1.39 mIU/L], IGF1 [109 vs. <25 ng/mL], fT3 [3.7 vs. 2.5 pmol/L] and fT4 [1.45 vs. 0.84 ng/mL]. Concomitantly, there was dramatic improvement in oocyte quality (no abnormal morphologies) and embryo quality (grade A), allowing an embryo transfer with successful pregnancy. CONCLUSIONSː This is the first report illustrating changes in hormonal levels in follicular fluid and the beneficial effect of GH replacement on oocyte and embryo quality during an IVF procedure in a patient with hypopituitarism. These results suggest that GH replacement is beneficial for oocyte quality in patients with GHD.

Aberrantly Expressed Non-Coding RNAs in the Placenta and Their Role in the Pathophysiology of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM), one of the most common complications during pregnancy, is associated with a high risk of short- and long-term adverse effects on the mother and offspring. Placenta-derived hormones and cytokines aggravate maternal insulin resistance (IR) during pregnancy, which in turn contribute to GDM. The hyperglycemia and IR in GDM result in aberrant placental structure and function adversely affecting fetal growth and well-being. Therefore, it is reasonable to assume that structural and functional alterations in the placenta contribute to the pathogenesis of GDM and GDM-related complications. Increasing evidence suggests that multiple non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs, and circular RNAs, are dysregulated in placentas of patients with GDM and linked to abnormal placental structure, metabolism, and function. Manipulation of ncRNA expression led to some key pathophysiological features of GDM, such as trophoblast dysfunction, changes in intracellular glucose metabolism, and inflammation. Moreover, placenta-specific ncRNAs may be potential diagnostic biomarkers and even therapeutic targets for GDM. This review summarizes data published on the involvement of aberrantly expressed placental ncRNAs in GDM and provides information on their role in the pathogenesis of GDM and GDM-associated complications.

A common deletion in the growth hormone receptor gene (d3-GHR) in the offspring is related to maternal placental GH levels during pregnancy

BACKGROUND

A common growth hormone receptor polymorphism with deletion of exon 3 (d3-GHR) has previously been linked to increased postnatal growth on the one hand and decreased fetal growth on the other. Regulation of fetal growth is positively dependent on secretion of placental GH (hGH-V).

OBJECTIVE

We explored the effect of the fetal d3-GHR genotype on maternal serum levels of hGH-V and fetal growth. The cellular localization of hGH-V synthesis and the GH receptors were determined in normal placentas.

METHODS

43 healthy mother-child pairs were examined during pregnancy with measurements of hGH-V during third trimester, and serial ultrasound measurements determined fetal growth rate. Birth anthropometrics were obtained. The GHR genotype of the child was analysed postnatally. Immunohistochemical (IHC) analysis was conducted on four placentas.

RESULTS

The presence of the d3-GHR genotype was associated with a markedly reduced concentration of hGH-V in maternal serum (β -0.52, SE 0.24, p = 0.04) compared to those who had a fl/fl genotype. Accordingly, a tendency towards reduced fetal growth rate during third trimester (β -25.8, SE 12.7, p = 0.05) and a lower birth weight were found among carriers of the d3-GHR allele, but these associations did not reach statistical significance (p = 0.08). IHC analysis showed expression of placental GH and GHR in the villous syncytiotrophoblast, the extravillous trophoblast, and the decidual cells and smooth muscle cells in chorionic vessels.

CONCLUSIONS

The presence of the d3-GHR polymorphism in the fetus was associated with lower maternal serum levels of hGH-V, decreased fetal growth rate in third trimester and lower birth weight compared to the wildtype.

Why Do Normal Children Have Acromegalic Levels of IGF-I During Puberty?

CONTEXT

The rapid pubertal height growth is unique to humans, but why do we have it? Although the spurt contributes 13% to 15% to the final adult height, we hypothesized that the biological significance of the high acromegalic levels of GH and IGF-I, which are behind the pubertal growth spurt, might primarily occur to stimulate the reproductive organs.

EVIDENCE SYNTHESIS

Animal data have demonstrated that adult Igf1 and Igf2 gene knockout mice that survive show a dramatic reduction in the size of the reproductive organs and are infertile. In humans, case reports of mutations in the genes affecting the GH-IGF axis and growth (GH, GHRH, GH-R, STAT5b, IGF-I, IGF-II, IGF-1R, PAPPA2) are also characterized by delayed pubertal onset and micropenis. Furthermore, GH treatment will tend to normalize the penile size in patients with GH deficiency. Thus, the endocrine effects of high IGF-I levels might be needed for the transition of the sexual organs, including the secondary sex characteristics, from the "dormant" stages of childhood into fully functioning reproductive systems. The peak IGF-I levels, on average, occur 2 years after the peak height growth velocity, suggesting reasons other than longitudinal growth for the high IGF-I levels, and remain high in the years after the height spurt, when the reproductive systems become fully functional.

CONCLUSION

We suggest that the serum levels of IGF-I should be monitored in children with poor development of sexual organs, although it remains to be investigated whether GH should be added to sex steroids in the management of hypogonadism for some pubertal children (e.g., boys with micropenis).

Pathophysiological changes associated with sleep disordered breathing and supine sleep position in pregnancy

Sleep is a complex and active physiological process that if disrupted, can result in adverse outcomes both within and outside of pregnancy. Sleep disordered breathing (SDB) occurs in 10-32% of pregnancies. Substantial physiological changes occur during pregnancy that impact on maternal sleep, which typically deteriorates with advancing gestation. Pregnancy challenges maternal homeostatic regulation of many systems which effect maternal sleep, including the respiratory, cardiovascular, endocrine, and immune systems. SDB can result from varying degrees of airway compromise and potentially cause systemic hypoxia. The hypoxia may be acute, intermittent or chronic in nature with complications dependant on the duration and the gestation at which the insult occurs. It is unlikely that this effect is mediated by a singular mechanistic pathway but results from a complex cascade of events across multiple maternal organ systems. Regardless of the etiology, both SDB and supine sleep position are associated with a variety of obstetric and perinatal complications including, pre-eclampsia/eclampsia, gestational diabetes mellitus, cardiomyopathy, heart failure, fetal growth restriction, poor neonatal condition at birth, stillbirth and neuro-psychiatric problems in offspring. Both maternal sleep position and sleep disordered breathing are potentially modifiable or treatable factors that if addressed have the potential to improve maternal and fetal outcomes. This narrative review summarizes the maternal and placental pathophysiological aberrations associated with sleep disordered breathing and supine sleep position in pregnancy.

Determinants of Maternal Insulin Resistance during Pregnancy: An Updated Overview

Insulin resistance changes over time during pregnancy, and in the last half of the pregnancy, insulin resistance increases considerably and can become severe, especially in women with gestational diabetes and type 2 diabetes. Numerous factors such as placental hormones, obesity, inactivity, an unhealthy diet, and genetic and epigenetic contributions influence insulin resistance in pregnancy, but the causal mechanisms are complex and still not completely elucidated. In this review, we strive to give an overview of the many components that have been ascribed to contribute to the insulin resistance in pregnancy. Knowledge about the causes and consequences of insulin resistance is of extreme importance in order to establish the best possible treatment during pregnancy as severe insulin resistance can result in metabolic dysfunction in both mother and offspring on a short as well as long-term basis.

Human Placental Growth Hormone Variant in Pathological Pregnancies

Growth hormone (GH), an endocrine hormone, primarily secreted from the anterior pituitary, stimulates growth, cell reproduction, and regeneration and is a major regulator of postnatal growth. Humans have two GH genes that encode two versions of GH proteins: a pituitary version (GH-N/GH1) and a placental GH-variant (GH-V/GH2), which are expressed in the syncytiotrophoblast and extravillous trophoblast cells of the placenta. During pregnancy, GH-V replaces GH-N in the maternal circulation at mid-late gestation as the major circulating form of GH. This remarkable change in spatial and temporal GH secretion patterns is proposed to play a role in mediating maternal adaptations to pregnancy. GH-V is associated with fetal growth, and its circulating concentrations have been investigated across a range of pregnancy complications. However, progress in this area has been hindered by a lack of readily accessible and reliable assays for measurement of GH-V. This review will discuss the potential roles of GH-V in normal and pathological pregnancies and will touch on the assays used to quantify this hormone.

Maternal exposure to UV filters: associations with maternal thyroid hormones, IGF-I/IGFBP3 and birth outcomes

BACKGROUND

Several chemical UV filters/absorbers ('UV filters' hereafter) have endocrine-disrupting properties in vitro and in vivo. Exposure to these chemicals, especially during prenatal development, is of concern.

OBJECTIVES

To examine maternal exposure to UV filters, associations with maternal thyroid hormone, with growth factor concentrations as well as to birth outcomes.

METHODS

Prospective study of 183 pregnant women with 2nd trimester serum and urine samples available. Maternal concentrations of the chemical UV filters benzophenone-1 (BP-1) and benzophenone-3 (BP-3) in urine and 4-hydroxy-benzophenone (4-HBP) in serum were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The relationships between 2nd trimester maternal concentrations of the three chemical UV filters and maternal serum concentrations of thyroid hormones and growth factors, as well as birth outcomes (weight, height, and head and abdominal circumferences) were examined.

RESULTS

Positive associations between maternal serum concentrations of 4-HBP and triiodothyronine (T₃), thyroxine (T₄), insulin-like growth factor I (IGF-I) and its binding protein IGFBP3 were observed in mothers carrying male fetuses. Male infants of mothers in the middle 4-HBP exposure group had statistically significantly lower weight and shorter head and abdominal circumferences at birth compared to the low exposure group.

CONCLUSIONS

Widespread exposure of pregnant women to chemical UV filters and the possible impact on maternal thyroid hormones and growth factors, and on fetal growth, calls for further studies on possible long-term consequences of the exposure to UV filters on fetal development and children's health.

Manipulation of the Growth Hormone-Insulin-Like Growth Factor (GH-IGF) Axis: A Treatment Strategy to Reverse the Effects of Early Life Developmental Programming

Evidence from human clinical, epidemiological, and experimental animal models has clearly highlighted a link between the early life environment and an increased risk for a range of cardiometabolic disorders in later life. In particular, altered maternal nutrition, including both undernutrition and overnutrition, spanning exposure windows that cover the period from preconception through to early infancy, clearly highlight an increased risk for a range of disorders in offspring in later life. This process, preferentially termed “developmental programming” as part of the developmental origins of health and disease (DOHaD) framework, leads to phenotypic outcomes in offspring that closely resemble those of individuals with untreated growth hormone (GH) deficiency, including increased adiposity and cardiovascular disorders. As such, the use of GH as a potential intervention strategy to mitigate the effects of developmental malprogramming has received some attention in the DOHaD field. In particular, experimental animal models have shown that early GH treatment in the setting of poor maternal nutrition can partially rescue the programmed phenotype, albeit in a sex-specific manner. Although the mechanisms remain poorly defined, they include changes to endothelial function, an altered inflammasome, changes in adipogenesis and cardiovascular function, neuroendocrine effects, and changes in the epigenetic regulation of gene expression. Similarly, GH treatment to adult offspring, where an adverse metabolic phenotype is already manifest, has shown efficacy in reversing some of the metabolic disorders arising from a poor early life environment. Components of the GH-insulin-like growth factor (IGF)-IGF binding protein (GH-IGF-IGFBP) system, including insulin-like growth factor 1 (IGF-1), have also shown promise in ameliorating programmed metabolic disorders, potentially acting via epigenetic processes including changes in miRNA profiles and altered DNA methylation. However, as with the use of GH in the clinical setting of short stature and GH-deficiency, the benefits of treatment are also, in some cases, associated with potential unwanted side effects that need to be taken into account before effective translation as an intervention modality in the DOHaD context can be undertaken.

Multiple Effects of Growth Hormone in the Body: Is it Really the Hormone for Growth?

In this review, we analyze the effects of growth hormone on a number of tissues and organs and its putative role in the longitudinal growth of an organism. We conclude that the hormone plays a very important role in maintaining the homogeneity of tissues and organs during the normal development of the human body or after an injury. Its effects on growth do not seem to take place during the fetal period or during the early infancy and are mediated by insulin-like growth factor I (IGF-I) during childhood and puberty. In turn, IGF-I transcription is dependent on an adequate GH secretion, and in many tissues, it occurs independent of GH. We propose that GH may be a prohormone, rather than a hormone, since in many tissues and organs, it is proteolytically cleaved in a tissue-specific manner giving origin to shorter GH forms whose activity is still unknown.

Neuroendocrine Regulation of Growth Hormone Secretion

This article reviews the main findings that emerged in the intervening years since the previous volume on hormonal control of growth in the section on the endocrine system of the Handbook of Physiology concerning the intra- and extrahypothalamic neuronal networks connecting growth hormone releasing hormone (GHRH) and somatostatin hypophysiotropic neurons and the integration between regulators of food intake/metabolism and GH release. Among these findings, the discovery of ghrelin still raises many unanswered questions. One important event was the application of deconvolution analysis to the pulsatile patterns of GH secretion in different mammalian species, including Man, according to gender, hormonal environment and ageing. Concerning this last phenomenon, a great body of evidence now supports the role of an attenuation of the GHRH/GH/Insulin-like growth factor-1 (IGF-1) axis in the control of mammalian aging.

Early pregnancy IGF-I and placental GH and risk of epithelial ovarian cancer: A nested case-control study

Insulin-like growth factor-I (IGF-I) signaling may promote ovarian tumor development by exerting mitotic, antiapoptotic and proangiogenic effects. During pregnancy, maternal production of IGF-I is regulated by placental growth hormone (GH). Parity is an established protective factor for ovarian cancer, however, no prior study has evaluated placental GH and IGF-I in pregnancy and epithelial ovarian cancer (EOC). Prior prospective studies on the association between IGF-I and EOC in nonpregnant populations were inconclusive and did not address associations in subtypes of EOC. Among members of the Finnish Maternity Cohort and the Northern Sweden Maternity Cohort, we identified 1,045 EOC cases, diagnosed after recruitment (1975-2008) and before March 2011 and 2,658 individually matched controls. Placental GH and IGF-I were measured in serum from the last pregnancy before EOC diagnosis or selection as control. We used conditional logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for tertiles and a doubling of hormone concentrations. Higher IGF-I was associated with a nonsignificant decrease in risk for invasive [ORT3 vs. T1 : 0.79 (0.62-1.02); ptrend  = 0.07] and endometrioid tumors [ORT3 vs. T1 : 0.55 (0.28-1.07); ptrend  = 0.07]. The protective association between higher IGF-I levels and risk of invasive EOC was stronger in analyses limited to women aged <55 years at diagnosis [ORT3 vs. T1 : 0.74 (0.57-0.96); ptrend  = 0.03]. Our study provides the first data on placental GH and IGF-I in pregnancy and EOC risk overall and by subtype. Our data suggest higher IGF-I levels in pregnancy may be associated with lower risk of invasive and endometrioid EOC.

Sleep fragmentation and false memories during pregnancy and motherhood

Pregnant women, both before and after childbirth, frequently experience memory deficits and disrupted sleep. In the present study we assessed the relationship between false memory generation and fragmented sleep during pregnancy and motherhood. We tested 178 pregnant women and 58 female non-pregnant childless controls, during pregnancy (15-35th week of gestation) and again after childbirth (8-13th month). False memories were defined as memories of gist words that were semantically related to studied word lists but were not presented during learning of these lists in the Deese-Roediger-McDermott (DRM) paradigm. Sleep was monitored by actigraphy in the home environment for seven consecutive nights. Compared to the controls, the group of pregnant women produced more false memories and displayed more fragmented sleep both during pregnancy and after childbirth. However, false memory generation was not correlated to measures of sleep fragmentation. These results show that pregnant women suffer from sleep fragmentation and a higher susceptibility to false memories, but leave open the question as to whether both phenomena are related.

Alterations in physiology and anatomy during pregnancy

Pregnant women undergo profound anatomical and physiological changes so that they can cope with the increased physical and metabolic demands of their pregnancies. The cardiovascular, respiratory, haematological, renal, gastrointestinal and endocrine systems all undergo important physiological alterations and adaptations needed to allow development of the fetus and to allow the mother and fetus to survive the demands of childbirth. Such alterations in anatomy and physiology may cause difficulties in interpreting signs, symptoms, and biochemical investigations, making the clinical assessment of a pregnant woman inevitably confusing but challenging. Understanding these changes is important for every practicing obstetrician, as the pathological deviations from the normal physiological alterations may not be clear-cut until an adverse outcome has resulted. Only with a sound knowledge of the physiology and anatomy changes can the care of an obstetric parturient be safely optimized for a better maternal and fetal outcome.

Does the dawn phenomenon have clinical relevance in normal pregnancy?

OBJECTIVE

The dawn phenomenon is a transient rise in blood glucose between 4 and 6 am that is attributed to the pulsatile release of pituitary growth hormone (GH). In pregnancy, GH is suppressed by placental GH. Hence, we hypothesize that there is no evidence for the dawn phenomenon in late pregnancy in healthy women.

STUDY DESIGN

Twenty glucose-tolerant women with singleton gestations between 28 weeks and 36 weeks 6 days' gestation were recruited. The women were admitted overnight to the Clinical Research Unit and had continuous glucose monitoring. Insulin and GH were measured at 2-hour intervals from 8 pm to 8 am. GH was grouped into times 1A (8-10 pm), 2A (12-2 am), and 3A (4-8 am) for changes over time. Further analysis was performed with time 1B (8 pm to 2 am) and 2B (4-8 am). Insulin was measured between 4 and 8 am.

RESULTS

Plasma glucose decreased over time (P < .001). There were no significant changes in GH among times 1A, 2A, and 3A (P = .45) or times 1B and 2B (P = .12). Insulin concentrations increased after meals, but there were no changes from 4 am (8.5 ± 1.4 μU/mL) through 8 am (8.6 ± 1.1 μU/mL; P = .98).

CONCLUSION

Glucose and insulin concentrations show no increase from 4-8 am; although there is variability in GH, there is no evidence for the dawn phenomenon in late pregnancy in healthy women.

Hypoglycaemia during pregnancy in women with Type 1 diabetes

AIMS

To explore incidence, risk factors, possible pathophysiological factors and clinical management of hypoglycaemia during pregnancy in women with Type 1 diabetes.

METHODS

Literature review.

RESULTS

In women with Type 1 diabetes, severe hypoglycaemia occurs three to five times more frequently in early pregnancy than in the period prior to pregnancy, whereas in the third trimester the incidence of severe hypoglycaemia is lower than in the year preceding pregnancy. The frequency distribution of severe hypoglycaemia is much skewed, as 10% of the pregnant women account for 60% of all recorded events. Risk factors for severe hypoglycaemia during pregnancy include a history with severe hypoglycaemia in the year preceding pregnancy, impaired hypoglycaemia awareness, long duration of diabetes, low HbA(1c) in early pregnancy, fluctuating plasma glucose values (≤ 3.9 mmol/l or ≥ 10.0 mmol/l) and excessive use of supplementary insulin injections between meals. Pregnancy-induced nausea and vomiting seem not to be contributing factors.

CONCLUSIONS

Striving for near-normoglycaemia with focus on reduction of plasma glucose fluctuations during pregnancy should have high priority among clinicians with the persistent aim of improving pregnancy outcome among women with Type 1 diabetes. Pre-conception counselling, carbohydrate counting, use of insulin analogues, continuous subcutaneous insulin infusion (insulin pump) therapy and real-time continuous glucose monitoring with alarms for low glucose values might be relevant tools to obtain near-normoglycaemia without episodes of severe hypoglycaemia.

Growth hormone isoforms

Human growth hormone (GH) is a heterogeneous protein hormone consisting of several isoforms. The sources of this heterogeneity reside at the level of the genome, mRNA splicing, post-translational modification and metabolism. The GH gene cluster on chromosome 17q contains 2 GH genes (GH1 or GH-N and GH2 or GH-V) in addition to 2(-3) genes encoding the related chorionic somatomammotropin. Alternative mRNA splicing of the GH1 transcript yields two products: 22K-GH (the principal pituitary GH form) and 20K-GH. Post-translationally modified GH forms include N(alpha)-acylated, deamidated and glycosylated monomeric GH forms, as well as both non-covalent and disulfide-linked oligomers up to at least pentameric GH. GH fragments generated in the course of peripheral metabolism may be measured in immunoassays for GH. The GH-N gene is expressed in the pituitary, the GH-V gene in the placenta. Secretion of pituitary GH forms is pulsatile under control from the hypothalamus, whereas secretion of placental GH-V is tonic and rises progressively in maternal blood during the 2nd and 3rd trimester. Pituitary GH forms are co-secreted during a secretory pulse; no isoform-specific stimuli have been identified. There are minor differences in somatogenic and metabolic bioactivity among the GH isoforms, depending on species and assay system used. Both 20K-GH and GH-V have poor lactogenic activity. Oligomeric GH forms have variably diminished bioactivity compared to monomeric forms. GH isoforms cross-react in most immunoassays, but assays specific for 22K-GH, 20K-GH and GH-V have been developed. The metabolic clearance of 20K-GH and GH oligomers is delayed compared to that of 22K-GH. The heterogeneous mixture of GH isoforms in blood is further complicated by the presence of two GH-binding proteins, which form complexes with GH; isoform proportions also vary depending on the lag time from a secretory pulse because of different half-lives. GH forms excreted in the urine reflect monomeric GH isoforms in blood, but constitute only a minute fraction of the GH production rate. The heterogeneity of GH is one important reason for the notorious disparity among assay results. It also presents an opportunity for distinguishing endogenous from exogenous GH.

Lower levels of circulating IGF-I in Type 1 diabetic women with frequent severe hypoglycaemia during pregnancy

AIMS

Severe hypoglycaemia is a significant problem in pregnant women with Type 1 diabetes. We explored whether frequent severe hypoglycaemia during pregnancy in women with Type 1 diabetes is related to placental growth hormone (GH) and insulin-like growth factor I (IGF-I) levels.

METHODS

A prospective, observational study of 107 consecutive pregnant women with Type 1 diabetes. Blood samples were drawn for IGF-I and placental GH analyses at 8, 14, 21, 27 and 33 weeks. Severe hypoglycaemic events were reported within 24 h.

RESULTS

Eleven women (10%) experienced frequent severe hypoglycaemia (> or = 5 events), accounting for 60% of all events. Throughout pregnancy, IGF-I levels were 25% lower in these women (P < 0.005) compared with the remaining women, despite similar placental GH levels. Eighty per cent of the severe hypoglycaemic events occurred before 20 weeks when IGF-I levels were at their lowest. This finding was not explained by differences in insulin dose, median plasma glucose levels or glycated haemoglobin. History of severe hypoglycaemia the year preceding pregnancy and impaired hypoglycaemia awareness-being the only predictors of frequent severe hypoglycaemia in a logistic regression analysis-were not associated with IGF-I or placental GH levels at 8 weeks.

CONCLUSIONS

In women with Type 1 diabetes experiencing frequent severe hypoglycaemia during pregnancy, IGF-I levels are significantly lower compared with the remaining women despite similar placental GH levels. IGF-I levels are lowest in early pregnancy where the incidence of severe hypoglycaemia is highest. IGF-I may be a novel factor of interest in the investigation of severe hypoglycaemia in patients with Type 1 diabetes.

The effect of gestational age and labor on placental growth hormone in amniotic fluid

OBJECTIVE

Placental growth hormone (PGH) is produced by trophoblast. This hormone becomes detectable in maternal serum during the first trimester of pregnancy. Its concentration increases as term approaches and becomes undetectable within one hour of delivery. PGH has important biological properties, including somatogenic (growth promotion), lactogenic, and lipolytic activity. Recently, PGH has been detected in amniotic fluid (AF) of midtrimester pregnancies. The purpose of this study was to determine whether PGH concentrations in AF change with advancing gestational age and in labor at term.

DESIGN

AF was assayed for PGH concentrations in samples obtained from patients undergoing genetic amniocentesis between 14 and 18 weeks of gestation (n=67), normal patients at term not in labor (n=24), and pregnant women at term in labor (n=51). PGH concentrations were determined by ELISA. Non-parametric statistics were used for analysis.

RESULTS

(1) PGH was detected in all AF samples; (2) patients in the midtrimester had a higher median concentration of PGH in AF than those at term (midtrimester: median: 3140.5 pg/ml; range: 1124.2-13886.5 vs. term: median: 2021.1pg/ml; range: 181.6-8640.8; p<0.01); (3) there was no difference in the median concentration of PGH between women at term, not in labor, and those in labor (term not in labor: median: 2113.4pg/ml; range: 449.3-8640.8 vs. term in labor: median: 2004.1pg/ml; range: 181.6-8531.5; p=0.73).

CONCLUSIONS

(1) PGH is detectable in AF at both mid- and third trimesters; (2) the median AF concentration of PGH is significantly lower at term when compared to the second trimester; (3) labor at term is not associated with changes in the AF concentration of PGH. The role of this unique placental hormone now found in the fetal compartment requires further investigation.

Clinical and biochemical improvement in acromegaly during pregnancy

Numerous case reports of pregnancy in acromegaly exist, however detailed descriptions of changes in placental and pituitary GH and IGF-I throughout gestation are rare. A 19-yr-old female presented to this institution with signs and symptoms of a GH-secreting pituitary adenoma. Following transphenoidal hypophysectomy, she had 3 unplanned pregnancies, despite ongoing active disease. No pregnancy was complicated by glucose intolerance or hypertension and 3 healthy newborns were delivered near or at term. Clinical improvement was observed during each pregnancy, accompanied by IGF-I levels lower than in the non-pregnant state, the majority lying within the normal range. This was despite increasing placental GH levels, and was not consistent with previous reports in the literature. Further surgical and medical therapies for acromegaly failed to normalize nonpregnant GH or IGF-I levels in this woman. Estrogen is known to alter GH signaling via its interaction with Janus kinase/signal transducers and activators of transcription (JAK-STAT) pathways. We hypothesize that increasing concentrations of estrogen or other pregnancy-related hormones resulted in her clinical and biochemical improvement during pregnancy. This may be used for future therapeutic benefit.

Human placental growth hormone is increased in maternal serum in pregnancies affected by Down syndrome

OBJECTIVE

To evaluate the relationship between maternal serum levels of human placental growth hormone (hPGH) and fetal Down syndrome at gestational midtrimester.

METHODS

We retrospectively analyzed samples of serum from 21 women with Down syndrome pregnancies detected at gestational midtrimester. The samples were obtained at 16-23 weeks' gestation during amniocentesis for fetal karyotyping. Sixty-two serum samples were used as controls, which were obtained at 16-23 weeks' gestation from women with singleton, uncomplicated pregnancies, who gave birth to healthy neonates with a birth weight appropriate for gestational age. The hPGH levels were measured by a solid-phase immunoradiometric assay using 2 different epitopes.

RESULTS

The median hPGH values in the serum of the Down-syndrome-affected pregnancies were significantly higher (p < 0.05) than those of the normal pregnancies at 16-23 weeks' gestation: the median value in the serum was 9.4 ng/ml (5th to 95th percentiles = 1.49-39.03) versus 4.7 ng/ml (0.53-7.88).

CONCLUSION

The hPGH levels in maternal serum were found to be higher at 16-23 weeks' gestation in pregnancies affected by fetal Down syndrome. Further investigation is needed to examine if maternal serum hPGH could be used as an additional marker in prenatal screening of Down syndrome at gestational midtrimester.

Placental growth hormone is increased in the maternal and fetal serum of patients with preeclampsia

OBJECTIVES

Placental growth hormone (PGH) is a pregnancy-specific protein produced by syncytiotrophoblast and extravillous cytotrophoblast. No other cells have been reported to synthesize PGH Maternal. PGH Serum concentration increases with advancing gestational age, while quickly decreasing after delivery of the placenta. The biological properties of PGH include somatogenic, lactogenic, and lipolytic functions. The purpose of this study was to determine whether the maternal serum concentrations of PGH change in women with preeclampsia (PE), women with PE who deliver a small for gestational age neonate (PE + SGA), and those with SGA alone.

STUDY DESIGN

This cross-sectional study included maternal serum from normal pregnant women (n = 61), patients with severe PE (n = 48), PE + SGA (n = 30), and SGA alone (n = 41). Fetal cord blood from uncomplicated pregnancies (n = 16) and PE (n = 16) was also analyzed. PGH concentrations were measured by ELISA. Non-parametric statistics were used for analysis.

RESULTS

(1) Women with severe PE had a median serum concentration of PGH higher than normal pregnant women (PE: median 23,076 pg/mL (3473-94 256) vs. normal pregnancy: median 12 157 pg/mL (2617-34 016); p < 0.05), pregnant women who delivered an SGA neonate (SGA: median 10 206 pg/mL (1816-34 705); p < 0.05), as well as pregnant patients with PE and SGA (PE + SGA: median 11 027 pg/mL (1232-61 702); p < 0.05). (2) No significant differences were observed in the median maternal serum concentration of PGH among pregnant women with PE and SGA, SGA alone, and normal pregnancy (p > 0.05). (3) Compared to those of the control group, the median umbilical serum concentration of PGH was significantly higher in newborns of preeclamptic women (PE: median 356.1 pg/mL (72.6-20 946), normal pregnancy: median 128.5 pg/mL (21.6-255.9); p < 0.01). (4) PGH was detected in all samples of cord blood.

CONCLUSIONS

(1) PE is associated with higher median concentrations of PGH in both the maternal and fetal circulation compared to normal pregnancy. (2) Patients with PE + SGA had lower maternal serum concentrations of PGH than preeclamptic patients without SGA. (3) Contrary to previous findings, PGH was detectable in the fetal circulation. The observations reported herein are novel and suggest that PGH may play a role in the mechanisms of disease in preeclampsia and fetal growth restriction.

Changes in circulating level of IGF-I and IGF-binding protein-1 from the first to second trimester as predictors of preeclampsia

OBJECTIVE

To assess whether circulating IGF-I and IGF-binding protein-1 (IGFBP-1) in the first and second trimester are associated with subsequent risk of preterm and term preeclampsia.

METHODS

Nested case-control study within a cohort of 29 948 pregnant women. Cases were women, who later developed preeclampsia, and controls were randomly selected women, who did not develop preeclampsia. IGF-I and IGFBP-1 were measured with ELISA in maternal blood samples that were collected in the first and second trimesters. We assessed associations of IGF-I and IGFBP-1 concentrations with later development of preterm (before the 37th week of gestation) and term preeclampsia.

RESULTS

An increase in IGF-I from the first to second trimester was associated with higher risk of preterm preeclampsia; the odds ratio (OR) for the highest compared with lowest quartile of increase was 4.9 (95% confidence interval, 1.1-21.8). Low concentrations of IGFBP-1, both in the first and in the second trimesters, were related to higher risk of term preeclampsia (OR 4.0, 95% confidence interval, 1.9-8.4) and moderately increased risk of preterm preeclampsia (OR 2.3, 95% confidence interval, 1.2-4.4).

CONCLUSION

The higher risk of preterm preeclampsia related to IGF-I increase may reflect placental disease, whereas low concentrations of IGFBP-1 associated with term preeclampsia may reflect maternal metabolic aberrations, indicating different etiologies in preeclampsia.

Treatment of acromegaly with pegvisomant during pregnancy: maternal and fetal effects

OBJECTIVE

Our objective was to describe the first case of the successful use of pegvisomant during pregnancy in a woman with acromegaly.

DESIGN

We present the case of a 26-yr-old female with acromegaly who had failed surgical and subsequent medical therapy but whose disease was well controlled on pegvisomant. She then conceived and was continued on pegvisomant throughout pregnancy. We then collected both maternal and cord blood samples at parturition, and later analyzed her breast milk.

RESULTS

Maternal IGF-I was well controlled during gestation. Fetal GH and IGF-I were within the normal range. Maternal pegvisomant levels were consistent with a 25-mg daily dosage. Fetal pegvisomant levels were minimal and near the range detected in untreated acromegalic patients, likely representing minimal cross-reactivity from endogenous GH or spurious contamination by maternal blood. GH variant levels in the maternal blood and the cord blood were both within the normal ranges. Pegvisomant levels in breast milk were below the lower limit of quantification of the assay and similar to those observed when analyzing breast milk samples from normal mothers in the same assay. Fetal growth parameters were normal; the baby was healthy and showed no adverse signs.

CONCLUSIONS

Pegvisomant therapy during gestation was safe and effective in our patient. Transplacental passage of pegvisomant is either absent or minimal, with a concentration highly unlikely to convey any significant pharmacodynamic effects on the fetal GH and IGF-I system. In addition, there is no evidence of substantial secretion of pegvisomant into breast milk.

Insulin-like Growth Factor I in Pregnancy and Maternal Risk of Breast Cancer

BACKGROUND

The role of insulin-like growth factor (IGF)-I in breast cancer remains controversial, despite numerous reports on the association of the hormone with breast cancer or high-risk mammographic densities. We hypothesized that exposure to elevated IGF-I during early pregnancy, a period characterized by intense cell proliferation in the breasts and in the presence of high concentrations of sex steroids, will be associated with increased maternal risk to develop a breast malignancy.

METHODS

The Northern Sweden Maternity Cohort is an ongoing prospective study, collecting blood samples from first-trimester-pregnant women since 1975 as part of screening for infectious diseases. A case-control study (212 cases and 369 controls) was nested among Northern Sweden Maternity Cohort members who delivered singleton babies. RIA was used to measure IGF-I and IGF-II levels. Conditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (95% CI).

RESULTS

Breast cancer risk increased with increasing IGF-I (top tertile OR, 1.7; 95% CI, 1.1-2.7). The association was stronger among the primiparous (OR, 2.2; 95% CI, 1.1-4.4) than in the nonprimiparous women (OR, 1.4; 95% CI, 0.7-2.8). Upper-tertile risks seemed to decrease within the <28-, 28 to 33, and >33-year groups of age at sampling, from 2.5 (0.9-7.6) to 2.1 (0.9-5.0) and 1.2 (0.5-2.5), respectively. There was no association of breast cancer with first-trimester-pregnancy IGF-II.

CONCLUSIONS

The study offers further evidence that IGF-I is important in breast cancer. Our findings suggest that the adverse effect of IGF-I on the breast may be stronger before the remodeling of the gland induced by a first pregnancy.

Peripartum maternal and foetal ghrelin, growth hormones, IGFs and insulin interrelations

OBJECTIVE

Ghrelin may influence GH secretion and is associated with insulin sensitivity. In pregnancy, placental growth hormone (PGH) replaces GH. The aim of this study was to investigate the relationship between PGH and ghrelin and their relationship to insulin sensitivity in pregnancy.

DESIGN

Prospective, descriptive study.

PATIENTS

Thirty-seven singleton pregnant and six twin pregnant women

MEASUREMENTS

Maternal blood samples were drawn before and 2 days after elective caesarian section (CS). Serum total ghrelin, PGH, GH, GH-binding protein, insulin and IGF-I and IGF-II, and plasma glucose were determined. Insulin sensitivity indices (ISIs) were calculated. Cord blood samples were drawn at delivery for ghrelin determination.

RESULTS

Serum ghrelin only displayed a minimal, although statistically significant, decrease after CS. Prior to delivery serum PGH increased by 25% during fasting, and was undetectable the day after CS. Serum levels of GH were low until 48 h after CS. No significant correlations were detected between PGH or ghrelin and ISIs, although a trend was observed for ghrelin. Twin pregnancies had higher PGH levels than singletons; however, levels of IGFs were similar. In cord blood, ghrelin levels were higher in arterial than venous samples.

CONCLUSIONS

Maternal ghrelin levels were only minimally affected by parturition, suggesting that maternal ghrelin is not involved in the transition from PGH to GH secretion. The increased arterial ghrelin levels in the foetus suggest foetal ghrelin production. Serum PGH appears to be influenced by fasting. Finally, elevated PGH levels in twin pregnancies do not appear to affect maternal IGF levels.

Aspects of placental growth hormone physiology

Placental growth hormone (PGH) has been known for 20 years. Nevertheless, its physiology is far from understood. In this review, basal aspects of PGH physiology are summarised and put in relation to the highly homologous pituitary growth hormone (GH). During normal pregnancy, PGH progressively replaces GH and reach maximum serum concentrations in the third trimester. A close relationship to insulin-like growth factor (IGF)-I and -II levels is observed. Furthermore, PGH levels are positively associated to fetal growth. The potential importance of growth hormone receptors and binding protein for PGH effects is discussed. Finally, the review outlines current knowledge of PGH in pathological pregnancies.

Kinetics and secretion of placental growth hormone around parturition

OBJECTIVE

During pregnancy, placental growth hormone (PGH) is secreted into the maternal circulation, replacing pituitary GH. It is controversial whether PGH levels decline during vaginal birth. After placental expulsion, PGH is eliminated from the maternal blood. GH binding protein (GHBP) and body mass index (BMI) influence GH kinetics, but their impact on PGH kinetics is unknown. The present study was undertaken to define the kinetics of PGH during vaginal delivery and Caesarian section and to relate these kinetics to GHBP and BMI.

DESIGN

A short term, prospective cohort study.

METHODS

Twelve women had repeated blood samples drawn during vaginal delivery. From 26 women undergoing planned Caesarian delivery (CS) repeated blood samples were withdrawn before, during and after the CS, allowing PGH half-life determination.

RESULTS

During vaginal delivery, median PGH values did not change before expulsion of the placenta, although individual fluctuations were seen. Clearance of PGH from the maternal circulation was best described by a two-compartment model. The initial half-life of serum PGH was (mean +/- s.d.) 5.8 +/- 2.4 min, and the late half-life was (median) 87.0 min (range: 25.1-679.6 min). The late half-life was correlated to the pre-gestational BMI (r = 0.39, P = 0.047), but not to the serum GHBP concentration.

CONCLUSIONS

Serum PGH did not decrease significantly during vaginal delivery. Elimination of PGH fitted a two-compartment model, with an estimated initial half-life of 5.8 min. The late phase serum half-life of PGH was related to BMI, suggesting a role for maternal fat mass in PGH metabolism.

Ghrelin and its relationship to growth hormones during normal pregnancy

OBJECTIVE

Ghrelin and GH secretagogue receptors have been found in reproductive organs, including the placenta. The physiology of ghrelin in pregnancy has not been explored. In human pregnancy, pituitary GH is gradually replaced by placental GH (PGH). The present study was undertaken to examine serum ghrelin levels during normal pregnancy and to determine to what extent changes in ghrelin levels coincide with changes in serum levels of free and total GH and PGH. Design Prospective study with blood sampling from pregnant women in gestational weeks 8, 18, 26 and 36 and postpartum.

PATIENTS

Eleven nondiabetic pregnant women with singleton pregnancies.

MEASUREMENTS

Serum ghrelin was determined using an in-house radioimmunoassay. Serum PGH was determined in a solid-phase immunoradiometric assay, serum GH and insulin in a time-resolved immunofluorometric assay, and serum GHBP in an in-house immunofunctional assay.

RESULTS

Serum ghrelin levels peaked in week 18 (1.20 +/- 0.09 microg/l) and the lowest levels were observed in late third trimester (0.87 +/- 0.06 microg/l), corresponding to a mean decrease of 27.7% (P < 0.001) from peak levels. An increase was observed again postpartum. Serum GH diminished throughout pregnancy to low third-trimester values (0.12 +/- 0.03 microg/l; P < 0.001), and PGH increased to 25.7 +/- 2.86 microg/l (P < 0.001) in week 36. Neither total nor calculated free levels of growth hormones correlated to ghrelin levels, and no significant correlations were observed between ghrelin and maternal body mass index (BMI) or fasting insulin levels.

CONCLUSIONS

Serum ghrelin levels peak around mid-gestation in human pregnancy. Ghrelin levels during pregnancy are at their lowest in the third trimester at a time of increased body weight, development of insulin resistance and high serum levels of PGH. However, no associations were observed between ghrelin and the two growth hormones.

Intrauterine growth retardation and consequences for endocrine and cardiovascular diseases in adult life: does insulin-like growth factor-I play a role?

Low birth weight has been associated with an increased incidence of ischaemic heart disease (IHD) and type 2 diabetes. Endocrine regulation of fetal growth by growth hormone (GH) and insulin-like growth factor (IGF)-I is complex. Placental GH is detectable in maternal serum from the 8th to the 12th gestational week, and rises gradually during pregnancy where it replaces pituitary GH in the maternal circulation. The rise in placental GH may explain the pregnancy-induced rise in maternal serum IGF-I levels. In the fetal compartment, IGF-I levels increase significantly in normally growing fetuses from 18 to 40 weeks of gestation, but IGF-I levels are four to five times lower than those in the maternal circulation. Thus IGF-I levels in fetal as well as in maternal circulation are thought to regulate fetal growth. Circulating levels of IGF-I are thought to be genetically controlled and several IGF-I gene polymorphisms have been described. IGF-I gene polymorphisms are associated with birth weight in some studies but not in all. Likewise, IGF-I gene polymorphisms are associated with serum IGF-I in healthy adults in some studies, although some controversy exists. Serum IGF-I decreases with increasing age in healthy adults, and this decline could hypothetically be responsible for the increased risk of IHD with ageing. A recent nested case-control study found that adults without IHD, but with low circulating IGF-I levels and high IGF binding protein-3 levels, had a significantly increased risk of developing IHD during a 15-year follow-up period. In summary, the GH/IGF-I axis is involved in the regulation of fetal growth. Furthermore, it has been suggested that low IGF-I may increase the risk of IHD in otherwise healthy subjects. Hypothetically, intrauterine programming of the GH/IGF axis may influence postnatal growth, insulin resistance and consequently the risk of cardiovascular disease. Thus IGF-I may serve as a link between fetal growth and adult-onset disease.

Placental growth hormone during pregnancy in a growth hormone deficient woman with type 1 diabetes compared to a matching diabetic control group

In pregnancy, pituitary growth hormone (GH) is gradually replaced by placental growth hormone (hPGH). GH deficient pregnant women may take advantage of GH substitution during pregnancy, but this issue still remains unresolved. Also, in pregnancy diabetes may cause macrosomia. The combination of GH deficiency, GH substitution therapy and type 1 diabetes mellitus may influence pregnancy in unforeseen ways. We present a case of pregnancy in a GH deficient woman with type 1 diabetes who continued on GH replacement until week 21. In gestational week 37 a thin and mildly small-for gestational-age (length 55 cm, +3 SD, 99th centile and weight 2445 g., -1.4 SD, 10th centile) but otherwise healthy boy was born. The patient had levels of serum hPGH at the lower end of the range of values found in a matching group of diabetic women. Serum IGF-I levels were at the upper end of the range of values in the control group. A positive correlation between serum hPGH and IGF-I values was seen in the control group when using the area-under-the-curve (r=0.84; p<0.001). The patient's child had lower birth weight and ponderal index, but was otherwise healthy. Serum IGF-I, but not hPGH, correlated to the absolute birth weight (r=0.63; p=0.015) and the birth weight z-score (r=0.55; p=0.039) in the control group. Serum hPGH and IGF-I declined rapidly after delivery. In conclusion, hPGH correlated to IGF-I in type 1 diabetes mellitus (DM), and IGF-I values correlated to the birth weight. Both type 1 diabetes mellitus and GH deficiency (with GH substitution therapy) may influence fetal growth, and in combination, the net influence may be difficult to predict.