Blood-Pressure Rise in Pregnancy Linked to Childhood Obesity

Liam Davenport

October 03, 2017

Women whose blood pressure rises during pregnancy may increase the risk of their children developing obesity, even if their blood pressure stays within the normal range, the results of a prospective study indicate.

The research, in over 85,000 woman-child pairs, revealed that the children of women who were hypertensive in the second trimester were 49% more likely to be overweight or obese in childhood, while hypertension in the third trimester increased the risk by 14%, compared with normotensive women.

Even among normotensive women, the risk of overweight or obesity in their children was increased by 5% to 8% if their blood pressure increased from prepregnancy levels during the second or third trimester.

The research was published online in the Journal of Clinical Endocrinology & Metabolism on September 27.

Ju-Sheng Zheng, PhD, of Qingdao University, China, and the University of Cambridge, United Kingdom, said in a press release: "Our study is the first to demonstrate that, among pregnant women, elevated blood pressure is associated with a greater risk of overweight and obesity for their children.

"The risk still existed for children of women who didn't have hypertension, but whose blood pressure during pregnancy was at the high end of the normal range."

Dr Zheng underlined that pregnant women should therefore be monitored to try to prevent substantial increases in blood pressure in mid- to late pregnancy: "This may help reduce the likelihood of their children being affected by obesity."

BP Up in Second and Third Trimester Among Normotensive Linked to Child Obesity

Childhood obesity is associated with a number of risk factors related to pregnancy and early life, such as parental obesity, birth weight, breastfeeding vs formula feeding, and rapid weight gain during infancy.

However, while some studies have suggested that hypertensive disorders during pregnancy are weakly linked to offspring body mass index (BMI) and obesity, none have prospectively examined the relationship.

The researchers therefore used the Jiaxing Birth Cohort of 338,413 live mother-child pairs who lived in the Jiaxing area of China and were enrolled between 1999 and 2013 to examine the issue.

The mothers visited their local clinics regularly during pregnancy, during which blood-pressure measurements were taken, and their prepregnancy anthropometric measurements were gathered from a premarriage health check database.

The children underwent health checks and anthropometric measurements at 1 to 2, 3, 6, 9, and 12 months during infancy, every 6 months until aged 36 months, and thereafter yearly until the ages of 6 to 7 years.

Excluding mother-child pairs with extreme offspring birth weight or preterm birth and those with missing blood-pressure recordings, as well as those whose children had missing anthropometric data, the researchers included 88,406 pairs in their analysis.

The mean maternal age at the birth of their offspring was 25 years, while the mean maternal BMI was 20.5 kg/m2.

The mean maternal diastolic blood pressure (DBP) increased from 68.4 mm Hg in the first trimester to 69.1 mm Hg in the second and 75.3 mm Hg in the third trimester. The mean maternal systolic blood pressure (SBP) increased from 105.9 mm Hg to 108.7 mm Hg and 115.2 mm Hg, respectively.

At the final follow-up, the children had a mean age of 5.9 years. The team notes that 6.6% were overweight and 2.5% were obese at this stage.

Overweight/obesity was associated with these factors in the mothers — younger age, higher BMI, earlier age of menarche, higher education levels, first pregnancy, and cesarean delivery.

Among normotensive women, first-trimester blood pressure was not associated with offspring overweight/obesity, after taking into account maternal BMI and height.

Changes in blood pressure from the first to the third trimester in normotensive women were positively associated with offspring overweight/obesity, at an odds ratio (OR) per 10-mm-Hg increase in DBP of 1.06 and an OR per 10-mm-Hg rise in SBP of 1.05.

Maternal Hypertension in Second and Third Trimester Ups Risk of Obesity in Offspring

And while maternal hypertension (>140/90 mm Hg) in the first trimester was not linked to offspring overweight/obesity, there was an association with hypertension in the second and third trimester, at ORs of 1.49 and 1.14, respectively.

 "These findings provide new insights into the biologic mechanisms linking to childhood obesity," the authors note.

They say their results confirm some previous research "and add novel evidence that maternal second- and third-trimester BP are positively associated with offspring overweight/obesity in women without hypertension."

The results also "sugggest that monitoring and control of the BP rise from middle to late pregnancy might be important, not only for pregnancy outcomes but also for the prevention of childhood obesity," the authors stress.

This work is supported by the National Basic Research Program of China; by National Natural Science Foundation of China; and by the PhD Programs Foundation of Ministry of Education of China. Dr Zheng is supported by the Marie Skłodowska-Curie Fellowships. The authors report no relevant financial relationships.

J Clin Endocrinol Metab. Published online September 27, 2107. Article

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