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Next Lesson - Physiology of the Fetus
Contents
Abstract
- Gestational diabetes is a condition of pregnancy relating to insulin resistance that most commonly resolves following delivery. It increases risk of macrosomia and fetal death, and can be treated with insulin and diet modification. Risk factors include mothers over 25 years old, obese mothers or a family history of the condition.
- Pre-eclampsia involves new hypertension after 20 weeks with new proteinuria, maternal organ dysfunction or uteroplacental dysfunction. It can first present after birth. Risk factors include age over 40, obesity and family history. Management includes antihypertensives and appropriately timed birth, followed by continued maternal monitoring.
Core
Gestational diabetes is a condition characterised by episodes of hyperglycaemia during pregnancy due to insulin resistance. However, gestational diabetes often resolves following birth. It is important to have a baseline for insulin resistance before pregnancy, because some women may be very likely to develop gestational diabetes if they are already resistant to insulin, or unable to produce adequate insulin.
Clinical implications of gestational diabetes can be serious and include:
- Increased incidence of miscarriage.
- Increased risk of congenital malformation, particularly when hyperglycaemia is present early in pregnancy. This risk is reduced with good glycaemic control.
- Increased incidence of macrosomia (a larger than normal baby). Macrosomia increases risk of shoulder dystocia which is an obstetric emergency. Shoulder dystocia is when the shoulders of the baby get stuck in the birth canal. This can lead to significant fetal morbidity and mortality. There can also be a risk to the mother of post partum haemorrhage and perineal tears. Brachial plexus injury to the baby is also possible.
- Increased risk of gestational hypertension and pre-eclampsia.
- Increased risk of developing Type 2 Diabetes Mellitus (T2DM) after delivery.
Diagnosis is achieved through a 75 g oral glucose tolerance test (2 hour glucose >7.8 mmol/L) or a fasting glucose of 5.6 mmol/L or more. Mothers at risk of gestational diabetes are screened with an oral glucose tolerance test.
- Dietary modification, similar to initial management of T2DM, focusing on balanced meals and controlled carbohydrate intake.
- Dietician input
- Medication - metformin and insulin can be considered if target blood sugar is not achieved.
- Regular fetal monitoring, particularly of growth, to prepare for macrosomia.
- Maternal BMI over 30
- Family history of diabetes of any sort
- Family history of macrosomia (as these might have been cases of undiagnosed gestational diabetes)
- Previous baby above 4.5 kg or previous history of gestational diabetes
- Ethnicity with high diabetes prevalence - South Asian, Afro-Caribbean, Middle Eastern
Pre-eclampsia is a potentially serious multisystem disorder. In a previously normotensive woman, it is defined by new hypertension after 20 weeks (systolic blood pressure of 140 mmHg or more and/or diastolic blood pressure of 90 mmHg or more) with new proteinuria, maternal organ dysfunction or uteroplacental dysfunction, such as fetal growth restriction. Proteinuria is not essential when the other diagnostic features are present. Pre-eclampsia can also first present after birth.
The pathophysiology of pre-eclampsia is complex and incompletely understood. Inadequate remodelling of the maternal spiral arteries can contribute to placental hypoperfusion and dysfunction. Placental factors acting on the maternal circulation contribute to systemic endothelial dysfunction, vasoconstriction and increased vascular permeability. This produces hypertension and can injure several organs; glomerular endothelial injury can cause proteinuria. Reduced uteroplacental perfusion can also impair fetal growth.
- Headache
- Visual disturbances
- Hyperreflexia
- Oedema
- Seizures
- Right upper quadrant pain (liver related pain)
- Maternal age over 40
- Maternal obesity
- Personal or family history of pre-eclampsia.
- Birth and delivery of the placenta address the placental component of pre-eclampsia. Timing depends on gestation and maternal and fetal condition. The disorder can persist or first present after birth, so treatment and monitoring must continue as clinically indicated.
- Antihypertensives
Edited by: Dr. Ben Appleby
Reviewed by: Dr. Thomas Burnell
Quiz
- 5005
