Maternal diabetes impacts oxygen flow in umbilical cord, study suggests

Pregnant women receiving an ultrasoundTo conduct the study, data from the St. Joseph's Health Care London Perinatal Database, which included information on almost 70,000 births from 1990 to 2011, was used. (mstandret/Envato Elements)

By Lawson Communications

A new study published in the journal Placenta has found a surprising difference in how pre-existing diabetes and gestational diabetes affect the oxygen supply in the umbilical cord during pregnancy.

The work has the potential to improve prenatal care for both mothers and babies in high-risk pregnancies, particularly those involving diabetes.

Currently, tests done very close to the end of a high-risk pregnancy can’t reliably measure the full health of the placenta and baby. Women with complications, such as diabetes, high blood pressure and an elevated BMI (body mass index), among others, are generally advised to induce labour before the full 40-week term.

“This study explored some of these high-risk pregnancies to better understand what occurs or changes in the placenta with the goal of eventually developing better tests,” said Dr. Barbra de Vrijer, associate professor, Department of Obstetrics & Gynaecology and associate scientist at Lawson Health Research Institute. 

To conduct this study, data from the St. Joseph's Health Care London Perinatal Database, which included information on almost 70,000 births from 1990 to 2011, was used. This information included details about birth weight, placental weight, and oxygen levels in the umbilical cord.

The study found that the number of blood vessels in the placenta (called vascularity) likely impacts oxygen in the umbilical vein, causing a slight increase in mothers with gestational diabetes, but a decrease in those with pre-existing diabetes.

Surprisingly, the research indicates that hyper-vascularity (too many blood vessels) in diabetic placentas may actually decrease oxygen transfer, potentially leading to more risk to the baby.

“When there is an increase in placental vascularity, crowding of the blood vessels can occur constraining their effective absorbing surface area for oxygen uptake from maternal blood within the placenta,” said Dr. Bryan Richardson, professor, Departments of Obstetrics & Gynaecology and Physiology & Pharmacology and scientist at Lawson.

The study also confirmed earlier research showing that in women with both pre-existing and gestational diabetes, who tend to have larger babies, the placentas were also disproportionately larger. This suggests that the placenta may not be working as efficiently as it should, relative to the baby's size.

While more research is needed, de Vrijer sees hope in the development of newer tests that look at factors like metabolic markers. These tests could help indicate if the placenta is insufficient and assist in decisions like whether and when to induce labour.

“There are new technologies that we are looking at studying moving forward,” said de Vrijer. “Our team is focused on continuing our research to better understand high-risk pregnancies with a goal of continuously improving care for pregnant individuals.”