Does Maternal Gestational Diabetes Increase the Offspring’s Risk of Hypertension?

Lifestyle can Impact Pregnant Woman’s Gestational Diabetes Risk

Moms, Save Your Kids The Risk of BP by Staying Healthy Before & During Pregnancy

Pregnancy brings about joy and happiness in the family. But as the news sets in, the couple and the entire family become concerned about the forthcoming journey until delivery working hard for a healthy pregnancy tenure and the delivery of a healthy baby. No time is too late for starting to lead a healthy life but the sooner, the better! Gearing up for pregnancy by becoming fit and healthy even before conceiving is the best way to safeguard against pregnancy complications but not many women follow this policy. While normal-weighted women may face pregnancy-related complications during the pregnancy course the risks are even higher for overweight/obese women. Obesity-related health conditions such as cardiovascular disease, chronic kidney diseases and type 2 diabetes are becoming more prominent with the ever-increasing obesity epidemic.

Hyperglycemia is the commonest metabolic disorder that paves way for aplenty pregnancy complications. Gestational diabetes mellitus (GDM) is any degree of glucose intolerance that’s first identified or whose onset happens during pregnancy. It also includes the possibility that glucose intolerance could have started the same time as pregnancy and almost 7% of pregnant women face this complication during their pregnancy. The prevalence rates are between 1 and 14% depending on the population. GDM is usually detected at 24 to 28 weeks of gestation on the basis of elevated plasma glucose levels on glucose tolerance testing. There is an increase in supply of glucose from the mother to her fetus during fetal growth and development. This stimulates the pregnant mom to develop insulin resistance to enable mother-fetus passage of glucose. There is not much of a change in insulin resistance during the first or second trimesters. But midway through the second trimester insulin requirements increase by 2.0- to 2.5-fold to optimize blood glucose levels of the pregnant mother and keeps her away from hyperglycemia. GDM is a condition that occurs when maximal insulin secretion cannot match the degree of insulin resistance. Hyperglycemia during pregnancy can have debilitating effects on the mother and the fetus increasing the risk of hypertension, pre-eclampsia, pre-term deliveries, macrosomia, fetal trauma, fetal hypoglycemia and low Apgar score. But the relationship between maternal GDM and the offspring’s risk of hypertension has been inconclusive. We have studies showing that offspring of moms with GDM had higher mean values of systolic blood pressure (SBP) or diastolic blood pressure (DBP) than children of those without GDM. Certain other studies showed no difference in BP readings between those with/without GDM.

Large-scale Study on the Risk of Hypertension in Kids whose Mothers Suffered from GDM
The study happened in China which included 578 non-GDM mother-child pairs and 578 children of mothers with GDM. All basic information about the mothers and their children were collected in the form of questionnaires. Height, weight, BMI and blood pressure measures were taken of all the participants involved in the study. In accordance with WHO guidelines, children’s BMI was classified as normal weight when BMI <85th percentile, overweight when BMI was >85th percentile and <95th percentile, and obese when BMI>95th percentile. Blood pressure measurements were declared to be high when SBP and/or DBP ≥90th percentile but <95th percentile in kids. Kids were called hypertensive when SBP and/or DBP ≥95th percentile. All analyses were adjusted for maternal age, gestational age, education, current smoking and treatment of GDM; kid’s outdoor activity time, vegetable and fruit intake frequency, screen watching time, sleep time and Z score for BMI-for-age. Mothers with GDM were older at the time of delivery, had higher pre-pregnancy BMI and also had less weight gain during pregnancy compared with women without GDM. They also had a higher birth weight, higher Z score for BMI, less sleeping time and were mostly overweight/obese compared to kids of mothers who did not have GDM. The mean value of age of the kids involved in the study was 5.9 years. Results showed that:
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1. Kids born to mothers with GDM had higher mean value of Z score for age-, sex- and height-specific SBP compared to kids born to moms without GDM. Difference in score for SBP between kids born to moms with GDM and those born to mothers without GDB was observed in both boys and girls but there was no difference in score for DBP between children born to mothers with/without GDM.
2. Children born to mothers with GDM had higher prevalence of hypertension and high blood pressure comparatively
3. In the multivariable analysis, the risk of high blood pressure in children born to mothers with GDM was present in boys and in children aged <5 years and ≥5 years but not found in girls.
   
   

The present study discussed here clearly shows that maternal GDM increases the risk of hypertension and high blood pressure in offspring. Hence, there is a dire need to control maternal GDM to avoid infant hypertension. We have two other Hong Kong and US studies showing that kids born to mothers with GDM had higher SBP value compared to children born to mothers without GDM. But there is yet another Hong Kong and UK study that could not find any link between maternal GDM and kid’s blood pressure rates. A Jerusalem perinatal study involved more than 60,000 singleton births and mothers with GDM were identified. Their kids were tested for several aspects at the age of 17 and this included testing for blood pressure as well. But results showed no link between GDM and systolic blood pressure. It was found that offspring of moms with high BMI suffered from high diastolic blood pressure (DBP) which shows that BMI and DBP are linked together more often than GDM and DBP. But, in another study consisting of Pima Indians systolic blood pressure in children aged 7-11 years was more when their moms suffered from GDM. The results remained the same even after adjusting for birth weight and childhood adiposity. Another study too showed increased systolic and mean arterial blood pressure in children of mothers with GDM even after adjusting for mean maternal BMI.

In Utero Exposure to Hyperglycemia Increases Risk of Blood Pressure Later in Life
The study here analyzed the relationship between maternal GDM, offspring adiposity and systolic blood pressure at the child’s three years of age. A total of 1,238 mother-child pairs were involved in the study where the mothers were generally older and had a lower mean pre-pregnancy BMI. All of the women were tested for GDM and those who tested positive were suggested to meet a nutritionist who corrected their diet, exercise and checked on their fasting blood sugar daily.

The child’s blood pressure readings were taken five times during a single visit. 1,020 infants had 5 measurements, 62 had 4, 28 had 3, 30 had 2 and 33 had 1 for a total of 5,525 measurements. The study used only systolic blood pressure readings and not diastolic pressure readings to predict later occurrence of blood pressure. Mother’s pre-pregnancy weight and height, paternal weight and height, smoking status, household income, paternal hypertension, history of diabetes, presence of GDM in the mother’s mother and paternal height and weight were noted down in the form of a questionnaire. Mean maternal age was 32 years and BMI 24.6. It was observed that 51% mothers suffered from GDM and an additional 152 (12%) of them from impaired glucose tolerance (IGT). It was also seen that these mothers were older and had higher pre-pregnancy BMI and pregnancy weight gain compared to those without GDM. Also, these moms mostly had a family history of DM and GDM.
At 3 years, children of those mothers with GDM had higher systolic blood pressure compared to those whose mothers did not suffer from gestational diabetes, almost 3.2 mmHg higher. Maternal IGT did not affect offspring blood pressure in any way.

Generally, woman with overweight/obesity, those who don’t do much physical activity, lead a sedentary lifestyle and have a family history of diabetes or moms with GDM are at a greater risk of suffering from GDM during pregnancy. Hence, every woman in her reproductive age is suggested to lead an active lifestyle that helps her maintain a healthy body weight and remain devoid of any health issues to sail through pregnancy smoothly and deliver a perfectly healthy baby. Though the relationship between maternal GDM and infant high blood pressure might seem inconclusive it is sure that those with maternal GDM are in for pregnancy related complications and high blood pressure in infants is also one of those.

References
Maternal Gestational Diabetes is Associated with Offspring’s Hypertension: https://academic.oup.com/ajh/article/32/4/335/5281125
Gestational Diabetes and the Offspring: Implications in the Development of the Cardiorenal Metabolic Syndrome in Offspring: https://www.karger.com/Article/FullText/337734
Intrauterine Exposure to Gestational Diabetes, Child Adiposity & Blood Pressure: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2761640/

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