This study evaluates the use of the STOPBANG questionnaire to predict whether a pregnant woman with class III obesity has obstructive sleep apnoea. All participants will have a STOPBANG score and modified STOPBANG score (substituting Epworth score > 10 with the tired item) calculated and then be tested with overnight pulse oximetry to see if they meet ODI criteria for obstructive sleep apnoea.

Obstructive sleep apnoea (OSA) is a condition in which the muscles and soft tissues of the throat collapse during sleep, resulting in them stopping breathing for a short period. It affects around 4% of all pregnant women and is more common in obese people. Pregnant women with untreated OSA are more likely to have pregnancy complications and are more likely to need a caesarean section. Babies born to mothers with untreated OSA are more likely to need neonatal treatment. If OSA is diagnosed and treated then these risks are reduced. In non-pregnant patients presenting for surgery, an screening tool called STOPBANG has been proven to be effective in identifying patients with OSA.

S: Do you Snore loudly? T: Do you often feel tired during daytime? O: Has anyone observed you stop breathing during your sleep? P: Do you have high blood pressure? B: Is your BMI >35 kg/m2? A: Are you >50 years old? N: Is your neck circumference >40cm? G: Is your gender male?

The investigators aim to assess whether STOPBANG can be used to identify OSA in obese pregnant women.

The aim is to recruit 100 pregnant women with a body mass index (BMI) ≥40 at Sunderland Royal Hospital. Data will be collected when they attend for their anomaly scan or glucose tolerance test (during the second trimester of pregnancy). Participants will complete an Epworth sleepiness scale questionnaire and the STOP questions before having their BMI, age and neck circumference documented. A STOPBANG score and Modified STOPBANG score (substitute tired question with Epworth >10) will be calculated. All participants will then take a Rad8 pulse oximeter home to record their overnight pulse rate and oxygen saturations. The oximetry results will be analysed by a respiratory physiologist and the oxygen desaturation index will be calculated. A statistician will analyse the results to determine if there is a relationship between STOPBANG score or Modified STOPBANG score and likelihood of the pregnant women having OSA. In a secondary analysis we will then see if any individual elements of STOPBANG can be used to predict OSA.

Inclusion Criteria:

• Pregnant women
• Body mass index ≥ 40 at first midwife appointment
• Women ≥ 18 years of age

Exclusion Criteria:

• Pre-existing obstructive sleep apnoea on treatment
• Pre-existing restrictive or obstructive respiratory disease
• Women with another cause of sleep apnoea (e.g. central sleep apnoea)
• Women under 18 years of age
• Women who do not provide or refuse consent
• Women lacking capacity to consent

Pregnant women booked to deliver at Sunderland Royal Hospital who have a body mass index ≥40 at their first midwife appointment.