How can I identify risk factors for shoulder dystocia in pregnant pati

Guideline-aligned answer with reasoning, red flags and references. Clinically reviewed by Dr Kola Tytler MBBS CertHE MBA MRCGP.

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 .
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 . These conditions can lead to a larger baby, increasing the risk of shoulder dystocia ,. Discussions about the timing and mode of birth are held with pregnant women with diabetes, especially in the third trimester .
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 . 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 . 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 . Maternal obesity can contribute to a larger baby, which is a risk factor for shoulder dystocia .

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