Maternal glucose homeostasis during pregnancy in women with overweight or obesity and markers of offspring adiposity, glycemia, and insulinemia

doi:10.21203/rs.3.rs-4359174/v1

Gestational diabetes mellitus (GDM) adversely affects offspring glucose homeostasis and markers of adiposity. Here, we examined the association between glycemia during pregnancy in overweight or obese women without GDM and markers of glucose homeostasis and adiposity in the offspring. Maternal fasting glucose and glucose concentrations 2-h after an oral glucose tolerance test (OGTT) were measured in 208 pregnant women with a pre-pregnancy body mass index (BMI) of 28-45 kg/m² without GDM. Offspring outcomes were collected at birth, 3, and 5 years of age. Linear mixed models with random effect of subject ID were used. No associations were found between maternal fasting or 2-h glucose concentrations with offspring fasting glucose and insulin concentrations from birth to 5 years of age. However, maternal fasting glucose in GW 28 and 36, and 2-h OGTT glucose in GW 28 were positively associated with C-peptide concentration at birth. Maternal fasting glucose at all time points during pregnancy was positively associated with BMI z-score at birth. Circulating blood glucose in pregnant women with overweight or obesity without GDM is positively associated with offspring C-peptide concentration and BMI z-score at birth but not with glucose and insulin concentrations during the first 5 years of life.

Health sciences/Biomarkers

Health sciences/Endocrinology

Health sciences/Endocrinology/Endocrine system and metabolic diseases

prevention of childhood obesity

fetal programming

maternal overweight/obesity

maternal glucose homeostasis

childhood glucose homeostasis

The prevalence of overweight and obesity among pregnant women is increasing¹. In 2018, about 40% of women in the reproductive age in the United States (aged 20–39 years) had obesity (BMI ≥ 30 kg/m²)² while in Denmark in 2021, about 40% of women aged 25–34 years had overweight (BMI ≥ 25 kg/m²) and 17% had obesity (BMI ≥ 30 kg/m²)³. Almost 6 out of 10 women with obesity prior to pregnancy exceed the recommendation for gestational weight gain (GWG)⁴. Maternal obesity and excessive GWG both increase the risk of pregnancy complications and offspring obesity during childhood and adulthood^5–8.

Insulin sensitivity decreases as gestation proceeds favoring a channeling of nutrient supply to the developing fetus⁹. High pre-pregnancy BMI and excessive GWG, alone or combined, are associated with decreased maternal insulin sensitivity which, during pregnancy, may lead to gestational diabetes mellitus (GDM)^10,11. Screening tools, as well as the threshold for GDM, differ across countries. World Health Organization (WHO) recommends a universal screening tool and defines GDM as a glucose concentration ≥ 10.0 or ≥ 8.5 mmol/L, 1-h and 2-h after an oral glucose tolerance test (OGTT) or a fasting glucose concentration of ≥ 5.1 mmol/L¹². In Denmark, a selective screening program is performed in women with one or more risk factors (e.g. BMI ≥ 27 kg/m²) for developing GDM. In Denmark, GDM is diagnosed if 2-h glucose concentration after an OGTT is ≥ 9.0 mmol/L¹³.

Maternal glucose dysregulation during pregnancy induces fetal hyperglycemia and hyperinsulinemia, stimulating fetal growth and leading to increased birthweight¹⁴. Offspring exposed to GDM in utero (WHO definition, 2013) have higher glucose concentrations after an OGTT and higher BMI at 7 years of age compared to offspring of women without GDM, but not different fasting glucose concentration¹⁵. This suggests that exposure to the GDM intrauterine environment can have long-term consequences for offspring glucose regulation and adiposity. Moreover, even in the absence of GDM, fasting maternal glucose concentrations are associated with risk of childhood obesity at age 10–14 years^16,17.

As the diagnostic criteria for GDM differ across countries, it is important to better understand the relationship between glucose homeostasis during pregnancy in non-GDM women with overweight and obesity with offspring health outcomes. This study examined the association of maternal fasting glucose concentrations in gestational weeks (GW) 15, 28, 36, and 2-h glucose concentrations after an OGTT in GW-28 with markers of adiposity and glucose homeostasis in the offspring born to women with overweight or obesity at birth, 3, and 5 years of age.

Study design

This paper includes data from the APPROACH (An Optimized Programming of Healthy Children) study, which was a randomized controlled trial (RCT) conducted at Copenhagen University Hospital Herlev-Gentofte and the University of Copenhagen, Department of Nutrition, Exercise, and Sports (Copenhagen, Denmark). The RCT included a dietary intervention in women during pregnancy and was conducted from January 2014 to December 2017. This was followed by a longitudinal cohort study of the offspring born to participating women. Data on the offspring was collected at birth, 3 and 5 years of age, and collected from June 2014 to January 2023. A detailed description of the APPROACH study design and methodology can be found elsewhere¹⁸. The study was approved by the Ethical Committee of the Capital Region of Denmark (VEK: H-3-2013-119) and was registered at ClinicalTrials.gov (NCT01894139). All study procedures were conducted in accordance with the Helsinki II Declaration.

Participants

Pregnant women received information about the study during their trans-nuchal scan (from 11 weeks and 4 days to 13 weeks and 6 days of gestation). Women were eligible for inclusion if they had a singleton pregnancy, had a pre-pregnancy BMI between 28–45 kg/m², and were older than 18 years. The women and their partner received both written and oral information about the study before signing an informed consent. Women were excluded if they developed GDM, defined in Denmark as a 2-h OGTT glucose concentration ≥ 9.0 mmol/L¹³, at any time point during the study.

Intervention

Included women were allocated in groups of 4–8 and subsequently randomized in a 1:1 ratio to one of two diets: i) the intervention diet characterized by high protein content (25% of total energy intake) and a low glycemic index of ~ 45, or ii) the control diet, with moderate protein content (18% of total energy intake) and a moderate glycemic index of ~ 54, aligning with the Nordic Nutritional Recommendations from 2012¹⁹. Fat provided ~ 30% of calories in both diets. The women received nutrition guidance from a clinical dietician and were instructed to consume the diets ad libitum ¹⁸.

Maternal anthropometry

At the baseline visit (GW 15), height was measured to the nearest 0.5 cm by a wall-mounted stadiometer (Seca, Germany), and body weight was measured to the nearest 0.1 kg by a medical scale (Tanita, Illinois, USA). Body weight was subsequently measured prior to every counseling session with the clinical dietitian (up to nine times during pregnancy). Accumulated GWG in GW 15, 28, and 36 was calculated as measured body weight at these time points minus pre-pregnancy body weight. Pre-pregnancy weight was self-reported or obtained by the general practitioner in GW 6–8. BMI was calculated as weight (kg) divided by height squared (m²). Parity was obtained by questionnaires and categorized as 0, 1, or ≥ 2.

Offspring anthropometry

At birth, midwives at the Copenhagen University Hospital Herlev-Gentofte obtained anthropometric measurements from the offspring. At 3 years (± 4 weeks) and 5 years (± 4 weeks) of age, anthropometric measurements were obtained by trained staff at the University of Copenhagen, Department of Nutrition, Exercise, and Sports, Copenhagen, Denmark.

At birth, the length was measured by using a non-elastic measuring tape to the nearest 0.5 cm. At 3 and 5 years of age, height was measured by using a wall-mounted stadiometer to the nearest 0.5 cm (Seca, Germany). Body weight at birth was measured by a medical beam scale (Tanita, USA) to the nearest 10 grams and at 3 and 5 years of age, body weight was measured by a bioelectrical impedance scale (InBody570, USA) to the nearest 100 grams.

Z-scores were calculated according to the WHO 2006 standards for sex-specific BMI-for-age²⁰ using the WHO Anthro software²¹ which includes children up to 60 months (5 years) of age. The WHO 2007 Reference for School-age Children and Adolescents (5 to 19 years) was used to calculate z-scores in children aged 61 months²².

Maternal blood markers

In GW 15, 28, and 36, venous blood samples from the women were drawn after an overnight fast (≥ 10 h) at the Copenhagen University Hospital Herlev-Gentofte. Samples were analyzed for fasting plasma glucose, glycated hemoglobin (HbA1c), C-peptide, total cholesterol, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, very-low lipoprotein (VLDL) cholesterol, and triglycerides (TG). Moreover, the participants performed a 2-h 75-gram OGTT in GW 28 at the Copenhagen University Hospital Herlev-Gentofte.

Offspring blood markers

Umbilical cord blood was collected at birth, and venous blood samples were collected at 3 years of age (after a 2-h fast) and at 5 years of age (after an overnight fast of ≥ 8 h). Samples were analyzed for fasting glucose, insulin, C-peptide, insulin growth factor-1 (IGF-1), insulin growth factor binding protein-3 (IGFBP-3), C-reactive protein (CRP), total cholesterol, LDL-cholesterol, HDL-cholesterol, and TG. All analyses were measured in plasma, except for glucose which was analyzed in whole blood.

Glucose at birth was measured using a colorimetric method, on a Pentra 400 analyzer (Horiba ABX). Fasting glucose at 3 and 5 years was analyzed on the same day as the blood sampling with Hemocue Glucose 201⁺ (HemoCue, Danmark).

Insulin, C-peptide, IGF-1, and IGFBP-3 were analyzed on Immulite 2000 (Siemens Healthcare, UK) and total cholesterol, LDL-cholesterol, HDL-cholesterol, TG, and CRP were analyzed on Pentra 400 (Horiba ABX SAS, France). For insulin concentration below 14.4 pmol/L (limit of detection), serum was used and analyzed with an ultrahigh sensitive insulin ELISA kit from Mercodia AB (cat no. 10-1132-01).

Statistical analysis

In this secondary analysis, the two diet arms of the primary RCT were pooled because there was no effect of the dietary intervention on maternal blood metabolic biomarkers¹⁸. To eliminate potential overlooked effects of the intervention, we adjusted for the allocated diet intervention group.

Histograms were used to visually evaluate data distributions. Characteristics of pregnant women and offspring are presented as mean ± standard deviation (SD) for normally distributed variables and as median with quartiles (Q1;Q3) for skewed variables. Categorical variables are presented as absolute and relative frequencies.

Available case analysis was carried out using a linear mixed model that included time as a fixed factor and subject ID as a random effect to examine the association of maternal fasting glucose concentrations in GW 15, GW 28, GW 36, and 2-h OGTT glucose concentration in GW 28 with offspring metabolic biomarkers and BMI z-score from birth to 5 years of age. We evaluated the linear mixed models for normal distribution using qq-plots and residual plots to check for heteroscedasticity and linearity. If the model did not fulfill the model assumptions, outcomes were log-transformed, and estimates and 95% CI were back-transformed and expressed as percentage changes. Otherwise, data was reported as estimates with 95% confidence intervals (CIs) and p-values. The analyses were adjusted for potential confounders, with Model 1 being crude (unadjusted) and Model 2 being adjusted for pre-pregnancy BMI, allocated diet intervention group, accumulated gestational weight gain, gestational age, maternal age, and parity. The association between maternal glucose concentrations and offspring BMI z-score (estimates and 95% CIs) is presented in forest plots. A p-value < 0.05 was used to determine statistical significance. All statistical analyses were performed using R studio (version 4.2.2).

A total of 209 offspring were born (one stillborn) (Fig. 1). Of the 208 mother-offspring dyads, 42 (~ 20%) dropped out before the 3-year follow-up, and 25 more (~ 15%) dropped out before the 5-year follow-up. Thus, a total of 208, 166, and 141 mother-offspring dyads at birth, 3, and 5 years, respectively, were included in the analysis.

Maternal characteristics

The pregnant women were 30.7 (± 4.79) years old and had a pre-pregnancy BMI of 32.8 (31.1;35.9) kg/m². Maternal fasting plasma glucose concentrations in GW 15, 28, and 36 were 5.04 (± 0.38), 4.93 (± 0.36), and 4.89 (± 0.39) mmol/L, respectively. Glucose concentration 2-h after the OGTT in GW 28 was 6.28 (± 0.97) mmol/L (Table 1).

Table 1

Maternal characteristics
	Pre-pregnancy		Gestational week 15		Gestational week 28		Gestational week 36
	N		N		N		N
Age	208	30.69 ± 4.79		-		-		-
Body height, m	208	1.68 ± 0.06		-		-		-
Body weight, kg	208	96.07 ± 12.71	204	96.26 ± 12.49	204	99.31 ± 12.21	190	102.70 ± 12.82
Gestational weight gain	208	-	204	0.37 ± 3.07	204	3.20 ± 4.45	190	6.55 ± 5.31
BMI	208	32.84 (31.12;35.91)	204	34.10 ± 3.83	204	35.1 ± 3.73	190	36.3 ± 3.99
Parity, no. (%)	207			-		-		-
0		115 (55.55%)
1		71 (34.30%)
≥2		21 (10.15%)
Fasting plasma glucose, mmol/L		-	203	5.04 ± 0.38	200	4.93 ± 0.36	191	4.89 ± 0.39
HbA1C, mmol/mol		-	203	31.99 ± 3.05	201	30.94 ± 3.27	192	33.59 ± 3.94
2h-OGTT, mmol/L		-			186	6.28 ± 0.97		-
C-peptide, pmol/l		-	190	518.0 (415.5;682.5)	185	669 (549;857)	179	854 (654;1045)
Cholesterol (mmol/L)		-	203	5.07 ± 0.91	201	6.10 ± 1.17	193	6.48 ± 1.32
TG (mmol/L)		-	203	1.48 ± 0.53	201	2.14 ± 0.71	193	2.74 ± 1.05
HDL (mmol/L)		-	203	1.54 ± 0.32	201	1.71 ± 0.40	193	1.65 ± 0.40
LDL (mmol/L)		-	203	2.87 ± 0.84	201	3.44 ± 1.11	189	3.65 ± 1.26
VLDL (mmol/L)		-	203	0.67 ± 0.24	201	0.96 ± 0.32	193	1.23 ± 0.47

BMI; Body mass index; HbA1c; Hemoglobin A1c; HDL; High-density lipoprotein; LDL; Low-density lipoprotein; OGTT; Oral glucose tolerance test; TG; Triglycerides; VLDL; Very-low-density lipoprotein. Pre-pregnancy outcomes are obtained at screening visit (gestational week 8–14). Data are presented as mean ± standard deviation for normally distributed variables, and as median (Q1;Q3) for skewed variables, or as absolute numbers and percentages (%) for categorical variables.

Offspring characteristics

At birth, 3, and 5 years of age, offspring glucose concentrations were 5.48 (± 0.37), 5.04 (± 0.57), and 5.08 (± 0.50) mmol/L, respectively; and insulin concentrations were 30.9 (19.1;64.1), 47.0 (19.3;90.5), and 16.2 (12.3;22.8) pmol/L, respectively. Offspring BMI z-scores were − 0.11 (-0.76;0.47), 0.61 (± 0.95), and 0.17 (± 0.98) at birth, 3, and 5 years, respectively (Table 2).

Table 2

Offspring characteristics at birth, 3- and 5 years of age
	Birth (n = 208)		3 years (n = 156)		5 years (n = 141)
	N		N		N
Gender, girls (%)		94 (45)		62 (40)		55 (39)
Age, days	208	0	156	1100 ± 13.3	141	1830 ± 14.0
Gestational age		282.5 (276.0;288.0)
Length/Height, cm	207	52.0 (51.00;53.00)	156	96.4 ± 3.57	140	113 ± 3.99
Body weight, kg	207	3.60 (3.32;3.90)	156	15.3 ± 1.57	141	19.9 ± 2.61
Length/height z-score	207	1.12 (0.59;2.07)	156	0.18 ± 0.94	141	0.62 ± 0.85
Weight z-score	207	0.59 (0.03;1.21)	156	0.54 ± 0.81	140	0.50 ± 0.89
BMI z-score	207	-0.11 (-0.76;0.47)	156	0.61 ± 0.95	140	0.17 ± 0.98
Glucose (mmol/L)	127	5.48 ± 0.37	119	5.04 ± 0.57	94	5.08 ± 0.50
Insulin (pmol/L)	123	30.90 (19.05;64.05)	114	47.00 (19.32;90.50)	83	16.2 (12.30;22.75)
C-peptide (pmol/L)	126	318.0 (212.5;454.5)	116	408 (229.2;605.0)	85	216 ± 81.9
IGF-1 (ng/mL)	125	55.85 ± 22.33	38	74.76 ± 29.18	85	94.1 ± 28.6
IGFBP-3 (ug/mL)	126	1.70 ± 0.39	38	3.24 ± 0.68	85	3.85 ± 0.68
CRP (mg/mL)	128	0.14 (0.13;0.16)	114	0.28 (0.14;0.72)	86	0.22 (0.12;0.62)
HOMA-IR	123	1.01 (0.60;2.22)	111	1.41 (0.60;2.81)	82	0.51 (0.37;0.72)
Cholesterol (mmol/L)	128	1.65 ± 0.41	116	3.76 ± 0.62	86	3.59 ± 0.56
TG (mmol/L)	128	0.51 (0.39;0.62)	116	0.78 (0.56;1.03)	86	0.52 (0.42;0.66)
HDL (mmol/L)	128	0.65 ± 0.17	116	1.23 ± 0.25	86	1.38 ± 0.24
LDL (mmol/L)	128	0.66 ± 0.23	116	2.16 ± 0.55	86	2.17 ± 0.52

CRP: C-reactive protein; HDL: High density lipoprotein; HOMA-IR: Homeostasis model assessment of insulin resistance IGF-1: Insulin-like Growth factor-1; IGFBP-3: Insulin-like growth factor binding protein 3; LDL: Low density lipoprotein; TG: Triglycerides; y: year. Data are presented as mean ± standard deviation for normally distributed variables, and as median (Q1;Q3) for skewed variables, or as absolute numbers and percentages (%) for categorical variables.

Maternal fasting glucose in GW 15 and offspring outcomes

No association was found between maternal fasting glucose concentration in GW 15 and offspring metabolic biomarkers. However, there was a positive association with offspring BMI z-score of 0.44 at birth (P = 0.028, model 2) (Table 3).

Table 3

Associations between Maternal fasting glucose in GW 15 and offspring blood markers
	Model 1				Model 2
	N¹	Estimate (95%CI)	P-value	N¹	Estimate (95%CI)	P-value
Glucose (mmol/L)	331			322
Birth		0.08 (-0.36;0.52)	0.716		0.12 (-0.29;0.61)	0.584
3y		0.08 (-0.36;0.52)	0.720		0.17 (-0.28;0.62)	0.466
5y		0.07 (-0.46;0.60)	0.797		0.12 (-0.41; 0.68)	0.652
Insulin (pmol/L)^*	316			306
Birth		1.19 (0.79;1.80)	0.407		1.19 (0.78;1.82)	0.425
3y		1.15 (0.76;1.73)	0.507		1.15 (0.75;1.76)	0.525
5y		1.03 (0.62;1.72)	0.902		1.02 (0.60;1.72)	0.940
C-peptide (pmol/L)^*	323			313
Birth		1.20 (0.93;1.56)	0.166		1.21 (0.93;1.57)	0.168
3y		1.16 (0.89;1.50)	0.271		1.17 (0.90;1.52)	0.248
5y		1.12 (0.81;1.54)	0.492		1.12 (0.81;1.54)	0.513
IGF-1 (ng/mL)	245			237
Birth		-1.45 (-13.09;10.17)	0.809		-1.86 (-13.52;9.88)	0.761
3y		-11.83 (-35.17;11.52)	0.324		-11.57 (-35.18;11.70)	0.343
5y		0.91 (-13.31;15.10)	0.901		0.76 (-14.73;14.00)	0.951
IGFBP-3 (ug/mL)	246			238
Birth		0.01 (-0.24;0.26)	0.932		0.02 (-0.24;0.27)	0.887
3y		-0.19 (-0.68;0.30)	0.457		-0.17 (-0.13;0.49)	0.521
5y		0.19 (-0.12;0.49)	0.232		0.18 (-0.13;0.49)	0.279
CRP (mg/mL)^*	324			314
Birth		1.04 (0.67;1.62)	0.855		1.05 (0.67;1.63)	0.842
3y		0.78 (0.50;1.21)	0.272		0.77 (0.49;1.21)	0.266
5y		0.67 (0.39;1.14)	0.140		0.66 (0.38;1.14)	0.138
BMI z-score	492			482
Birth		0.43 (0.03;0.83)	0.038		0.44 (0.06;0.83)	0.028
3 years		-0.30 (-0.75;0.15)	0.191		-0.32 (-0.76;0.11)	0.150
5 years		-0.07 (-0.55;0.41)	0.767		-0.07 (-0.54;0.40)	0.786

CRP: C-reactive protein; IGF-1: Insulin-like Growth factor-1; IGFBP-3: Insulin-like growth factor binding protein 3; y: year.

Model 1: Crude (unadjusted); Model 2: Adjusted for pre-pregnancy BMI, allocated intervention group, accumulated gestational weight gain in gestational week 15, gestational age, maternal age, and parity. Data were reported as estimates with 95% confidence intervals (CIs) and p-values using a linear mixed model with random effects of ID.*Unfitted models were log-transformed and estimates and 95% CIs were back-transformed and expressed as %.¹ Includes all observations at any time point.

Maternal fasting glucose in GW 28 and offspring outcomes

A 1.0 mmol/L increase in maternal fasting glucose concentration in GW 28 was associated with an increase in offspring C-peptide by 62% at birth (P < 0.001, model 2), a decrease in CRP by 48% at 3 years (P = 0.001, model 2), and a decrease in CRP by 62% at 5 years (P = 0.002, model 2). Moreover, BMI z-score increased by 0.56 at birth for every 1 mmol/L increase of maternal fasting glucose (P = 0.004, model 2) (Table 4).

Table 4

Associations between Maternal fasting glucose in GW 28 and offspring blood markers
		Model 1			Model 2
	N¹	Estimate (95%CI)	P-value	N¹	Estimate (95%CI)	P-value
Glucose (mmol/L)	326			321
Birth		-0.10 (-0.56;0.37)	0.688		-0.06 (-0.52;0.41)	0.815
3y		-0.13 (-0.60;0.34)	0.584		-0.10 (-0.57;0.38)	0.689
5y		0.20 (-0.37;0.77)	0.495		0.28 (-0.31;0.86)	0.362
Insulin (pmol/L)^*	310			304
Birth		1.50 (0.96;2.33)	0.076		1.50 (0.96;2.35)	0.084
3y		1.02 (0.65;1.60)	0.935		1.02 (0.64;1.62)	0.946
5y		0.90 (0.51;1.60)	0.716		0.87 (0.49;1.59)	0.658
C-peptide (pmol/L)^*	317			311
Birth		1.62 (1.23;2.13)	< 0.001		1.62 (1.23;2.14)	< 0.001
3y		1.04 (0.79;1.38)	0.780		1.05 (0.79;1.40)	0.760
5y		1.11 (0.78;1.60)	0.548		1.10 (0.76;1.60)	0.625
IGF-1 (ng/mL)	242			238
Birth		4.23 (-7.97;16.45)	0.501		1.46 (-10.95; 13.87)	0.822
3y		-22.79 (-50.28;4.67)	0.105		-23.24 (-50.96;3.85)	0.103
5y		7.66 (-8.14;23.46)	0.347		4.51 (-11.79;20.85)	0.597
IGFBP-3 (ug/mL)	243			239
Birth		0.09 (-0.17;0.35)	0.509		0.06 (-0.21;0.32)	0.686
3y		-0.31 (-0.88;0.26)	0.296		-0.31 (-0.89;0.26)	0.297
5y		0.20 (-0.13;0.54)	0.240		0.17 (-0.18;0.52)	0.358
CRP (mg/mL)^*	318			312
Birth		1.13 (0.71;1.80)	0.600		1.10 (0.69;1.76)	0.692
3y		0.55 (0.34; 0.89)	0.016		0.52 (0.32;0.84)	0.001
5y		0.40 (0.22;0.73)	0.003		0.38 (0.21;0.70)	0.002
BMI z-score	483			477
Birth		0.57 (0.192; 0.95)	0.003		0.56 (0.19;0.93)	0.004
3 years		-0.24 (-0.66; 0.18)	0.270		-0.28 (-0.70;0.13)	0.193
5 years		-0.26 (-0.70; 0.19)	0.260		-0.28 (-0.73;0.16)	0.216

CRP: C-reactive protein; IGF-1: Insulin-like Growth factor-1; IGFBP-3: Insulin-like growth factor binding protein 3; y: year.

Model 1: Crude (unadjusted); Model 2: Adjusted for pre-pregnancy BMI, allocated intervention group, accumulated gestational weight gain in gestational week 28, gestational age, maternal age, and parity. Data were reported as estimates with 95% confidence intervals (CIs) and p-values using a linear mixed model with random effects of ID. *Unfitted models were log-transformed and estimates and 95% CIs were back-transformed and expressed as %. ¹ Includes all observations at any time point.

Maternal fasting glucose in GW 36 and offspring outcomes

Maternal fasting glucose concentration in GW 36 was associated with an increase in offspring BMI z-score by 0.59 at birth (P = 0.001, model 2), an increase in C-peptide by 36% at birth (P = 0.022, model 2), and an increase in IGF-1 by 12.98 ng/mL (P = 0.034, model 2) at birth. In the unadjusted model, each 1.0 mmol/L increase in maternal fasting glucose concentration in GW 36 was associated with a decrease in offspring CRP of 41% at 5 years of age (P = 0.049), however, when adjusting for confounders, the association was attenuated (P = 0.073, model 2) (Table 5).

Table 5

Associations between Maternal fasting glucose in GW 36 and offspring blood markers
	Model 1			Model 2
	N¹	Estimate (95%CI)	P-value	N¹	Estimate (95%CI)	P-value
Glucose (mmol/L)	321			313
Birth		-0.26 (-0.69;0.17)	0.236		-0.34 (-0.76;0.09)	0.130
3y		-0.00 (-0.46;0.45)	0.992		-0.01 (-0.46;0.45)	0.982
5y		0.09 (-0.43;0.61)	0.730		0.15 (-0.38;0.68)	0.586
Insulin (pmol/L)^*	305			296
Birth		1.41 (0.95;2.09)	0.089		1.32 (0.88;1.98)	0.186
3y		1.02 (0.67;1.55)	0.934		1.04 (0.68;1.62)	0.853
5y		0.83 (0.51;1.37)	0.469		0.82 (0.49;1.38)	0.460
C-peptide (pmol/L)^*	312			303
Birth		1.41 (1.10;1.82)	0.008		1.36 (1.05;1.76)	0.022
3y		0.96 (0.73;1.26)	0.773		0.97 (0.74;1.29	0.836
5y		0.89 (0.64;1.23)	0.478		0.88 (0.63;1.23)	0.436
IGF-1 (ng/mL)	239			232
Birth		14.45 (3.18;25.74)	0.013		12.98 (1.34;24.62)	0.034
3y		-10.44 (-37.76; 16.77)	0.445		-7.87 (-35.82;18.65)	0.570
5y		0.07 (-14.06;14.17)	0.993		-0.84 (-15.43;13.90)	0.912
IGFBP-3 (ug/mL)	240			233
Birth		0.24 (-0.00;0.48)	0.058		0.23 (-0.01;0.48)	0.076
3y		0.06 (-0.51;0.62)	0.832		0.09 (-0.49;0.65)	0.746
5y		-0.00 (-0.30;0.30)	0.983		-0.01 (-0.33;0.30)	0.940
CRP (mg/mL)^*	313			304
Birth		1.14 (0.74;1.76)	0.556		1.14 (0.73;1.79)	0.565
3y		0.72 (0.45;1.16)	0.177		0.74 (0.45;1.21)	0.236
5y		0.58 (0.34;0.99)	0.049		0.59 (0.34;1.04)	0.073
BMI z-score	462			448
Birth		0.64 (0.29;0.98)	< 0.001		0.59 (0.23;0.94)	0.001
3 years		-0.13 (-0.52;0.27)	0.527		-0.24 (-0.64;0.16)	0.243
5 years		-0.21 (-0.62;0.21)	0.337		-0.28 (-0.70;0.15)	0.208

CRP: C-reactive protein; IGF-1: Insulin-like Growth factor-1; IGFBP-3: Insulin-like growth factor binding protein 3; y: year.

Model 1: Crude (unadjusted); Model 2: Adjusted for pre-pregnancy BMI, allocated intervention group, accumulated gestational weight gain in gestational week 36, gestational age, maternal age, and parity. Data were reported as estimates with 95% confidence intervals (CIs) and p-values using a linear mixed model with random effects of ID. *Unfitted models were log-transformed and estimates and 95% CIs were back-transformed and expressed as %. ¹ Includes all observations at any time point.

Maternal 2-h OGTT glucose concentration in GW 28 and offspring markers

Maternal 2-h glucose after an OGTT was associated with an increase in offspring C-peptide by 19% at birth (P = 0.001, model 2), an increase in IGFBP-3 by 0.11 ug/mL (P = 0.035, model 2) at birth, and a decrease in CRP by 29% (P = 0.003, model 2) at 5 years of age. No association was found between 2-h OGTT glucose concentration and BMI z-score (Table 6).

Table 6

Associations between Maternal 2-h OGTT in GW28 and offspring blood markers
	Model 1			Model 2
	N¹	Estimate (95%CI)	P-value	N¹	Estimate (95%CI)	P-value
Glucose (mmol/L)	317			311
Birth		-0.05 (-0.22;0.13)	0.588		-0.01 (-0.19;0.16)	0.892
3y		-0.04 (-0.21;0.13)	0.647		0.01 (-0.17;0.18)	0.947
5y		-0.07 (-0.27;0.13)	0.488		-0.05 (-0.24;0.15)	0.654
Insulin (pmol/L)^*	302			295
Birth		1.17 (0.99;1.38)	0.071		1.18 (1.00;1.39)	0.060
3y		0.99 (0.841;1.17)	0.910		0.98 (0.83;1.16)	0.816
5y		0.97 (0.79;1.19)	0.774		0.97 (0.79;1.19)	0.779
C-peptide (pmol/L)^*	308			301
Birth		1.17 (1.06;1.30)	0.003		1.19 (1.08;1.32)	0.001
3y		1.01 (0.91;1.11)	0.904		1.00 (0.90;1.11)	0.992
5y		0.95 (0.84;1.19)	0.400		0.95 (0.84;1.07)	0.391
IGF-1 (ng/mL)	233			229
Birth		2.97 (-1.57;7.52)	0.205		2.61 (-1.96;7.16)	0.274
3y		2.23 (-5.62;10.07)	0.582		1.94 (-5.81;9.70)	0.631
5y		-4.41 (-9.93;1.13)	0.122		-5.00 (-10.50;0.48)	0.082
IGFBP-3 (ug/mL)	234			230
Birth		0.11 (0.02;0.20)	0.025		0.11 (0.01;0.20)	0.035
3y		0.10 (-0.06;0.27)	0.213		0.10 (-0.06;0.26)	0.237
5y		-0.07 (-0.11;0.04)	0.209		-0.08 (-0.20;0.03)	0.170
CRP (mg/mL) ^*	309			302
Birth		0.95 (0.80;1.13)	0.568		0.96 (0.80;1.14)	0.640
3y		0.84 (0.71;1.01)	0.060		0.85 (0.71;1.02)	0.084
5y		0.72 (0.58;0.89)	0.003		0.71 (0.57;0.88)	0.003
BMI z-score	455			446
Birth		0.05 (-0.11;0.20)	0.550		0.12 (-0.04;0.26)	0.154
3 years		-0.05 (-0.22;0.12)	0.551		0.01 (-0.15;0.17)	0.938
5 years		-0.08 (-0.27;0.10)	0.370		-0.02 (-0.19;0.16)	0.852

CRP: C-reactive protein; IGF-1: Insulin-like Growth factor-1; IGFBP-3: Insulin-like growth factor binding protein 3; y: year.

Model 1: Crude (unadjusted); Model 2: Adjusted for pre-pregnancy BMI, allocated intervention group, accumulated gestational weight gain in gestational week 28, gestational age, maternal age, and parity. Data were reported as estimates with 95% confidence intervals (CIs) and p-values using a linear mixed model with random effects of ID. *Unfitted models were log-transformed and estimates and 95% CIs were back-transformed and expressed as %. ¹ Includes all observations at any time point.

In the current study we investigated markers of glucose homeostasis and adiposity in offspring born to women with overweight or obesity without GDM. This study found a positive association between maternal fasting glucose concentrations in GW 15, 28, and 36 with offspring BMI z-score at birth. However, none of these associations were found at 3 and 5 years of age. We did not find any significant associations between maternal fasting glucose concentrations in GW 15, 28, 36, and 2-h OGTT glucose concentration with offspring glucose and insulin concentrations from birth to 5 years of age. Nevertheless, maternal fasting glucose concentrations in GW 28, 36, and 2-h OGTT glucose concentrations were positively associated with offspring C-peptide concentrations at birth.

Contrary to C-peptide, the association with offspring insulin concentration did not reach statistical significance. C-peptide is co-secreted in equimolar amounts with insulin from the pancreatic β-cells²³, therefore, cord blood C-peptide concentration is considered an indicator of fetal β-cells function. The concentration of insulin is affected by many other physiological pathways—besides its rate of secretion—that affect the overall clearance of insulin from the circulation, which may have precluded a significant relationship from being observed. Technical errors during cord blood collection may also be involved: hemolysis in cord blood has been shown to affect insulin concentration as it causes degradation of insulin, whereas C-peptide is unaffected²⁴. Nonetheless, exclusion of samples that were hemolysed (n = 18) did not change the results. The positive association between maternal glycemia and offspring cord C-peptide might indicate that maternal glucose concentrations are related to β-cell function in the newborn. This is in line with the hypothesis that maternal hyperglycemia during pregnancy induces hyperglycemia in the offspring, as maternal glucose freely passes the placenta and stimulates the fetal pancreas to secrete more insulin, potentially leading to hyperinsulinemia¹⁴. Here, we demonstrate the association between maternal fasting glucose and offspring C-peptide among women with overweight or obesity without GDM, which might reflect a compensatory mechanism in the offspring being exposed to higher maternal glycemia during pregnancy.

The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) trial was designed to examine the association between maternal glycemia during pregnancy below the threshold for GDM with the risk of adverse pregnancy outcomes²⁵. This study found that increasing concentrations of maternal glucose below the diagnostic threshold for GDM were associated with offspring cord C-peptide among ~ 23,000 multi-ethnic mother-offspring dyads²⁶. Furthermore, maternal fasting glucose concentration, and glucose concentrations 1 and 2 h after an OGTT, were positively associated with an increased odds ratio for offspring cord blood C-peptide above the 90th percentile²⁶. Our findings are in line with these observations. Also, we did not observe any associations between maternal glucose homeostasis and offspring glucose concentrations from birth to 5 years of age. Interestingly, the HAPO follow-up study of the offspring at 10–14 years of age found a positive association of maternal fasting glucose in GW 28 and 2-h glucose after an OGTT with elevated fasting glucose in the offspring. These associations persisted after adjusting for both maternal BMI in pregnancy and child BMI z-scores at follow-up²⁷. Puberty is a dynamic transitional phase that challenges the glucose homeostatic system, as it typically involves an increase in insulin resistance and a compensatory increase in insulin secretion²⁸, which raises the possibility that programming occurring during the intrauterine life manifests in late childhood, around the time of puberty, when glucose homeostasis is challenged.

The present study also identified positive associations between maternal fasting glucose in GW 15, 28, and 36 with offspring BMI z-score at birth. This is consistent with the previous observation that maternal fasting, 1-h, and 2-h glucose concentrations are associated with the occurrence of birthweights above the 90th percentile²⁶. In our study, we further demonstrate these relationships do not persist by 3 and 5 years of age. This is in line with a HAPO sub-study, which conducted a follow-up of 1165 offspring and found no association between maternal glycemia in GW 28 and offspring BMI z-score at the age of 2 years²⁹. In an expanded follow-up cohort of 1320 offspring, the same study reported that maternal fasting glucose concentrations were positively associated with BMI z-score and sum of skinfolds at 5–7 years of age³⁰. However, the associations weakened after adjusting for maternal BMI, highlighting the importance of maternal pre-pregnancy BMI as an important confounder, which might, to some extent, explain the association between maternal glycemia during pregnancy and obesity risk in the offspring³⁰. Interestingly, the HAPO follow-up study examined offspring adiposity indexes including BMI z-score in 4832 offspring aged 10–14 years old and found a positive association with maternal fasting and post-OGTT glucose concentrations below the diagnostic criteria for GDM. These associations persisted even after adjusting for maternal BMI¹⁶. Despite adjusting for maternal pre-pregnancy BMI in our analyses, the associations of maternal glucose concentrations with offspring BMI z-score at birth remained unaffected.

In a prospective multicenter cohort study, offspring exposed to preexisting diabetes or GDM in utero had an increased risk of overweight/obesity by the age of 5.5 years. Furthermore, as offspring grew older, the risk of developing overweight or obesity increased notably among those whose mothers had diabetes compared to those whose mothers did not have diabetes³¹, suggesting that the associations between maternal glucose and offspring adiposity may not be apparent during early life. This finding is supported by a meta-analysis demonstrating a greater risk of overweight and obesity in offspring born to women with GDM or type 1 diabetes, and this was particularly evident during late childhood and adolescence³². This prompts speculation on whether the relationship between childhood obesity and maternal glycemia during pregnancy in women without GDM will manifest and be identifiable later in childhood.

An important strength of the present study is the longitudinal design consisting of data on markers of glucose homeostasis and adiposity from mother-offspring dyads during pregnancy and early childhood. Furthermore, this study includes women with overweight or obesity in a Danish setting, which allows us to investigate a larger spectra of maternal glucose concentrations as the diagnostic threshold for GDM is higher compared to other countries. This adds valuable information to the current literature in a high-risk population for developing GDM and the association with offspring health during early childhood. However, the findings presented in this paper rely on secondary analyses and should therefore be considered exploratory whereby causality cannot be established. Further, results from observational longitudinal studies are subject to confounding by co-existing behavioral and environmental factors challenging interpretation. Also, generalization of our findings to other populations is limited because of different diagnostic threshold for GDM, and differences in methodology and sample size between studies. This might explain some of the discordant associations reported in the literature.

In conclusion, maternal glucose concentrations during pregnancy in women with overweight or obesity who do not have GDM are positively associated with cord blood C-peptide concentration and BMI z-score in the offspring at birth, but not with glucose and insulin concentrations in the offspring during the first 5 years of life. Thus, adequate monitoring and optimal control of maternal glycemia during pregnancy may be important even when GDM is not present.

Funding

The Novo Nordisk Foundation funded this follow-up study of the offspring, while the APPROACH intervention study received support from The Nordea Foundation, Danish Pork Levy Foundation, Danish Agriculture & Food Council, Danish Dairy Foundation, LEGO Charity, PharmaNord, and Pharmo Vital. The funders played no role in study design, data collection, analysis, interpretation, or manuscript writing.

Acknowledgement

We thank all women participating in the study and the agreement for their children to participate in the currently ongoing cohort study. We thank the midwives and doctors at the Department of Pregnancy and Childbirth, Herlev and Gentofte Hospital, clinical dietician Annette Vedelspang, laboratory technician Søren Andresen, and ICH-GCP specialist Lene Stevner from the Department of Nutrition, Exercise and Sports, University of Copenhagen for their contributions to the APPROACH study.

Author contributions

The authors’ contributions were as follows – N.R.W.G. conceptualized the study and acquired the funding. C.S.M. and M.N. performed the data analysis and drafted the manuscript; F.M., N.R.W.G., C.M., and U.K.O. reviewed and edited the manuscript; C.S.M. and M.N. had full access to the data in the study and had the responsibility for the integrity of the data analysis. The corresponding author had complete access to all study data and final responsibility for submission. All authors read and approved the ﬁnal manuscript.

Conflict of interest

None of the authors reported a conflict of interest related to the study.

Data Share Statement

The datasets generated and/or analyzed during the current study are not publicly available due to privacy protection of the participants but are available from the corresponding author on reasonable request.

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No competing interests reported.

Maternal glucose homeostasis during pregnancy in women with overweight or obesity and markers of offspring adiposity, glycemia, and insulinemia

Status:

Journal Publication

Version 1

Abstract

Figures

Introduction

Methods

Study design

Participants

Intervention

Maternal anthropometry

Offspring anthropometry

Maternal blood markers

Offspring blood markers

Statistical analysis

Results

Maternal characteristics

Offspring characteristics

Maternal fasting glucose in GW 15 and offspring outcomes

Maternal fasting glucose in GW 28 and offspring outcomes

Maternal fasting glucose in GW 36 and offspring outcomes

Maternal 2-h OGTT glucose concentration in GW 28 and offspring markers

Discussion

Declarations

References

Additional Declarations

Status:

Journal Publication

Version 1