Antenatal dexamethasone and the growth hormone-insulin-like growth factor axis

Glycemic control following two regimens of antenatal corticosteroids in mild gestational diabetes: a randomized controlled trial

PURPOSE

To compare 3 consecutive days of hyperglycemic response following antenatal dexamethasone regimens of 12-mg or 6-mg doses 12 hourly in diet-controlled gestational diabetes.

METHODS

A randomized controlled trial was carried out in a university hospital in Malaysia. Women with lifestyle-controlled gestational diabetes scheduled to receive clinically indicated antenatal corticosteroids (dexamethasone) were randomized to 12-mg 12 hourly for one day (2 × 12-mg) or 6-mg 12-hourly for two days (4 × 6-mg). 6-point (pre and 2-h postprandial) daily self-monitoring of capillary blood sugar profile for up to 3 consecutive days was started after the first dexamethasone injection. Hyperglycemia is defined as blood glucose pre-meal ≥ 5.3 or 2 h postprandial ≥ 6.7 mmol/L. The primary outcome was a number of hyperglycemic episodes in Day-1 (first 6 BSP points). A sample size of 30 per group (N = 60) was planned.

RESULTS

Median [interquartile range] hyperglycemic episodes 4 [2.5-5] vs. 4 [3-5] p = 0.3 in the first day, 3 [2-4] vs. 1 [0-3] p = 0.01 on the second day, 0 [0-1] vs. 0 [0-1] p = 0.6 on the third day and over the entire 3 trial days 7 [6-9] vs. 6 [4-8] p = 0.17 for 6-mg vs. 12-mg arms, respectively. 2/30 (7%) in each arm received an anti-glycemic agent during the 3-day trial period (capillary glucose exceeded 11 mmol/L). Mean birth weight (2.89 vs. 2.49 kg p < 0.01) and gestational age at delivery (37.7 vs. 36.6 weeks p = 0.03) were higher and median delivery blood loss (300 vs. 400 ml p = 0.02) was lower in the 12-mg arm; all other secondary outcomes were not significantly different.

CONCLUSION

In gestational diabetes, 2 × 12-mg could be preferred over 4 × 6-mg dexamethasone as hyperglycemic episodes were fewer on Day-2, fewer injections were needed and the regimen was completed sooner.

CLINICAL TRIAL REGISTRATION

http://www.isrctn.com/ISRCTN16613220 .

The fetal fibronectin test is superior to cervical length measurement in predicting preterm birth in twin pregnancies: a retrospective observational study

OBJECTIVES

Twin pregnancies have a higher likelihood to experience spontaneous preterm birth (PTB). Those with imminent PTB need to be determined in order to undergo fetal lung maturation with glucocorticoids and therewith improve neonatal outcomes. The aim of this study was to assess the predictive value of the fetal fibronectin (fFN) test and the measurement of cervical length in twin pregnancies with symptoms of imminent PTB.

STUDY DESIGN

We performed an observational study on all twin pregnancies at the Medical University Vienna. Women were admitted to the hospital either due to symptoms of imminent PTB or due to a shortening of the cervical length before completed 34 weeks of gestational age. Logistic regression analysis was performed to assess the predictive value of the fFN test and cervical length on imminent preterm birth.

RESULTS

The data of 82 women with twin pregnancies were eligible, of which 10 (12 %) had a positive, 45 (55 %) a negative, 21 (26 %) an unclear fFN result, and 6 (7 %) showed missing data. Cervical length ≤20 mm did not show any statistical significant prediction of PTB in our study cohort. After 7 days, 4/10 (40 %) pregnant women with positive fFN test gave birth, while 4/45 (9 %) women with a negative fFN test gave birth. Within 14 days after hospitalization, 6/10 (60 %) women with a positive fFN test gave birth, compared to 4/45 (9 %) with a negative fFN test. The positive fFN test was a statistically significant predictor of PTB within 7 days (p = 0.02) and 14 days (p = 0.004), respectively.

CONCLUSION

The fFN test has the potential to detect women with twin pregnancies, who are at risk of giving birth within the following days. Hence, the practice of hospitalizing women solely due to the shortening of the cervical length cannot be supported.

Prenatal Glucocorticoid Treatment Completeness and Steroid Hormonal Levels as Related to Infant and Maternal Health

This study was conducted to confirm the negative associations between testosterone and cortisol levels and health and developmental outcomes in very low-birth weight (VLBW) infants after controlling for prenatal glucocorticoid (GC) treatment. Seventy-four VLBW infant-mother pairs were recruited from a neonatal intensive care unit in the Southeastern United States. We divided the pairs into the complete (n = 58) and incomplete (n = 16) GC treatment groups. Data on infants and mothers were obtained at birth, 40 weeks' postmenstrual age, and 3 and 6 months' corrected age. Salivary testosterone and cortisol levels of the pairs were determined at 40 weeks' postmenstrual age using enzyme immunoassay. Log-linear and general linear mixed models showed that gestational age and birth weight were lower when testosterone was 1 pg/mL higher. When cortisol was 1 μg/dL higher, technology dependence at discharge was higher and motor development at 6 months was lower. Mothers with complete GC treatment had greater parity and gravida, more prenatal visits, and more medical complications. The study outcomes supported our hypothesis that steroid hormonal levels are more predictive of infant health and development than GC treatment completeness. Single dose of GC treatment might be just as effective as 2 doses, although further study with more subjects would be needed to confirm. As the associations with steroid hormonal levels lasted longer than the GC treatment associations, we recommend confirming the predictive effects of testosterone and cortisol levels after 6 months.

Changes in maternal glucose metabolism after the administration of dexamethasone for fetal lung development

Aims. Antenatal dexamethasone administration for fetal lung development may impair maternal glucose tolerance. In this study, we investigated whether glucose and insulin levels differed among singleton and twin pregnancies and pregnancies with impaired glucose tolerance (IGT) after treatment with dexamethasone. Methods. Singleton pregnancies, twin pregnancies, and pregnancies with IGT between 28 and 33 weeks of gestation whose mothers were treated with dexamethasone were enrolled in this study. Exclusion criteria included gestational hypertension, diabetes, renal disorders, and infectious diseases. The fasting plasma glucose and insulin levels were checked before administration and 24 h, 48 h, and 72 h after treatment was completed. Results. Mean glucose levels were significantly higher in the twin pregnancy and IGT groups at 24 h and 48 h after the administration of dexamethasone than those in the singleton pregnancy group (P < 0.05). Although there was no significant difference in glucose levels before administration and 72 h after dexamethasone administration among the three groups, insulin levels in the IGT group were significantly higher (P < 0.05). Insulin levels in the singleton pregnancy group at 24 h and 48 h after treatment were significantly lower than in the twin and IGT groups. Conclusion. The effects on maternal fasting blood glucose and insulin levels of dexamethasone administrated to promote fetal lung maturation correlated with embryo number and the presence of IGT.

The prolonged effect of repeated maternal glucocorticoid exposure on the maternal and fetal leptin/insulin-like growth factor axis in Papio species

BACKGROUND

Maternal obesity represents a risk factor for pregnancy-related complications. Glucocorticoids are known to promote obesity in adults.

METHODS

We evaluated maternal and fetal metabolic changes during and after 3 weekly courses of betamethasone administered to pregnant baboons (Papio subspecies) at doses equivalent to those given to pregnant women.

RESULTS

Betamethasone administration during the second half of pregnancy increased maternal weight but neither maternal food intake nor fetal weight, as assessed at the end of gestation. Betamethasone increased maternal serum glucose concentration, the ratio of insulin-like growth factor-I and insulin-like growth factor binding protein-3, and serum leptin during treatment (normalized by 17, 35, and 45 days posttreatment, respectively, for each parameter). Maternal and fetal serum leptin concentrations did not differ between groups at the end of gestation.

CONCLUSION

Prolonged maternal hyperleptinemia caused by betamethasone administration in the second half of gestation did not change fetal metabolic parameters measured and placental leptin distribution at the end of gestation.

Influence of a single course of antenatal betamethasone on the maternal-fetal insulin-IGF-GH axis in singleton pregnancies

OBJECTIVE

We examined the hypothesis that a single course of antenatal betamethasone influences the maternal-fetal insulin-IGF-GH axis.

DESIGN

A prospective, observational, pilot study consisting of four groups of pregnant women: (I) received betamethasone and delivered <2 weeks post treatment; (II) received betamethasone and delivered >2 weeks post treatment; (III) untreated women who delivered <37 weeks (preterm controls); (IV) untreated women who delivered >37 weeks (term controls). Maternal and mixed umbilical cord blood was collected at delivery and analyzed for insulin, glucose, IGF-I, IGF-II, IGFBP-1, IGFBP-3, GH, and GHBP.

RESULTS

Betamethasone increased maternal insulin, glucose and IGF-I levels without affecting IGFBPs. In the fetal compartment, betamethasone treatment was associated with a delayed suppressive effect on GH and a sustained suppressive effect on IGF-II levels. There were no differences in infant size or neonatal morbidities between patients who delivered <2 weeks or >2 weeks post betamethasone treatment. In Group IV, birth weight correlated positively with cord IGF-I levels (r2=0.41, p=0.0098) and negatively with cord IGFBP-1 levels (r2=0.51, p=0.0039), and ponderal index correlated negatively with cord IGFBP-1 levels (r2=0.27, p<0.05).

CONCLUSIONS

A single course of antenatal betamethasone influences the maternal-fetal insulin-IGF-GH axis, particularly fetal IGF-II levels, without measurable anthropometric changes at birth. Whether these effects have implications beyond the neonatal period remains to be determined.

The role of maternal factors, postnatal nutrition, weight gain, and gender in regulation of serum IGF-I among preterm infants

IGF-I is important for somatic growth and development of the human fetus and neonate. IGF-I also plays an important role in normal vascularization of human retina, as it has been suggested that insufficient IGF-I may be a factor in the development of retinopathy of prematurity. The principal regulator of the bioavailability of IGF-I in the circulation is IGF binding protein 3 (IGFBP-3). The aim of this study was to study factors associated with postnatal serum concentrations of IGF-I and of IGFBP-3 in preterm infants from birth to an age corresponding to 40 wk postmenstruation. We conducted a prospective, longitudinal study in which we measured serum IGF-I and IGFBP-3 concentrations in 76 preterm infants from birth (postmenstrual ages 23-32 wk) until discharge from hospital around 40 wk. Information regarding nutrition, weight gain, maternal factors, and treatment with corticosteroids were collected weekly. Variables found to be associated with postnatal change over time of serum IGF-I and IGFBP-3 were postmenstrual age (p<0.001), weight gain (standard deviation score) (p<0.001), and enteral intake of protein (p<0.001). Male gender was associated with lower IGF-I levels (p<0.001). The relationship between protein intake and IGF-I (and also between protein intake and IGFBP-3) was positive, as was the relationship between weight gain and IGF-I (and between weight gain and IGFBP-3). These results indicate that the degree of prematurity, low enteral protein intake, male gender, and slow weight gain are associated with a slower postnatal increase of IGF-I in preterm infants.