During pregnancy, the placenta secretes hormones that increase insulin resistance, which may cause gestational diabetes (GD). Left untreated, diabetes can damage the placenta.

GD begins in the placenta, primarily with the hormone lactogen. While this hormone can help support fetal development, it also changes the metabolism of the pregnant person, increasing insulin resistance.

Insulin resistance is when the body has a decreased ability to respond to insulin, which means the body takes longer to clear glucose (sugar) from the blood. In some pregnant people, this induces GD.

Without treatment, GD can damage the placenta. High glucose can also cross the placenta and affect the developing fetus.

Read on to learn more about GD and the placenta.

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The relationship between GD and the placenta is bidirectional. This means that the placenta influences the development of GD, but GD also affects the development of the placenta.

Lactogen, a hormone the placenta produces, plays a key role in insulin resistance. A high level of lactogen in the body can contribute to GD.

The placenta helps nourish the fetus, providing it with oxygen and nutrients. Damage to the placenta can harm the developing fetus, which is one way GD can be harmful.

According to a 2021 paper, GD affects the blood vessels in the placenta. Earlier research suggests that these blood vessel changes may be a cause or product of increased inflammation in the placenta. This inflammation can reduce oxygen access for the fetus, increasing the risk of pregnancy and birth complications.

Additionally, glucose in the blood from GD can cross the placenta. This can affect the developing fetus and cause high blood sugar in the fetus.

GD is a risk factor for pregnancy and birth complications. The risk is much higher without treatment.

This is because it increases fetal exposure to blood glucose and causes the pregnant person to have ongoing elevated blood glucose.

However, it is important to note that not everyone with GD develops complications, and treatment can help make complications avoidable.

A doctor may recommend a person with GD has ongoing monitoring because of the increased risks for the pregnant person and the fetus.

Learn about the risks associated with untreated GD.

A note about sex and gender

Sex and gender exist on spectrums. This article will use the terms “male,” “female,” or both to refer to sex assigned at birth. Click here to learn more.

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A 2022 meta-analysis looked at research on outcomes in pregnancies where the pregnant person had GD. It is important to note that this study only included individuals who identified as female.

Compared with females without GD, those who did not use insulin had higher rates of:

Each of these can increase the risk of other complications. For example, a large fetal head can increase the risk of a difficult birth and birth complications.

The research did not find an increase in the rate of stillbirth, postpartum hemorrhage, low APGAR scores, or death shortly after birth.

The American Diabetes Association (ADA) recommends that all people with GD consult with a dietitian.

In most cases, the first line of treatment is dietary changes and an increase in activity to help manage blood glucose. This includes a low glycemic index diet.

A person should also monitor their blood glucose at home, typically by testing it several times each day.

If these treatments do not help, a person may need to take insulin. This replaces and supplements the body’s natural insulin to remove glucose from the blood.

A doctor may also recommend ongoing monitoring of the fetus, including biophysical profiles (special ultrasound that can check for signs of distress).

Having GD does not mean that a person will have issues during delivery. However, in some cases, doctors may suggest inducing labor or having a C-section.

Learn about what to expect from a GD care plan.

A pregnant person should have ongoing visits with a doctor or midwife during their pregnancy. These can help with detecting early signs of GD and continual assessment of the risk of birth complications.

Contact a doctor if:

  • home glucose monitoring shows an ongoing rise in blood glucose
  • home treatment is not working, and diet is not managing GD
  • a person feels sick or dizzy
  • a person has concerns about GD complications

If a person has GD, they can carefully manage their blood glucose with lifestyle changes, medication, and sometimes both.

Left untreated, GD can damage the placenta and increase the risk of pregnancy complications.

Glucose in the blood from GD can also cross the placenta, which can affect the developing fetus and cause it to develop high blood sugar.