How can I identify risk factors for shoulder dystocia in pregnant patients during routine antenatal care?

During routine antenatal care, several factors can indicate an increased risk of shoulder dystocia:

• Suspected Large-for-Gestational-Age (LGA) Baby: A higher chance of shoulder dystocia and brachial plexus injury is associated with vaginal birth when a baby is suspected to be large for gestational age ¹.
• Diabetes in Pregnancy: Women with type 1, type 2, or gestational diabetes are offered ultrasound monitoring of fetal growth and amniotic fluid volume at 28, 32, and 36 weeks ². These conditions can lead to a larger baby, increasing the risk of shoulder dystocia ¹,². Discussions about the timing and mode of birth are held with pregnant women with diabetes, especially in the third trimester ².
• Maternal Obesity: For women with a Body Mass Index (BMI) over 30 kg/m2 at the booking appointment, a risk assessment should be conducted in the third trimester, considering factors like mobility and comorbidities ¹. For those with a BMI over 30 kg/m2, particularly over 35 kg/m2, ultrasound scanning may be considered if fetal presentation is uncertain at the start of established labour ¹. Routine antenatal care includes measuring height and weight to calculate BMI, and testing for gestational diabetes is offered to anyone with a BMI over 30 kg/m2 ⁵. Maternal obesity can contribute to a larger baby, which is a risk factor for shoulder dystocia ¹.