Information for Pregnancies with Increased BMI
What is your BMI?
Body Mass Index or BMI is calculated by your weight to height ratio
When is your BMI calculated?
At your booking appointment the midwife will measure your weight and height; this will be entered
onto the computer system which automatically calculates your BMI. If your BMI is greater than 30
you will be booked for Consultant led care.
What does it mean for your pregnancy?
Pregnancies in women with increased BMI can be more complicated and require greater
monitoring throughout. If your BMI is greater than 30 you will be booked for Consultant Led Care
and advised to give birth in hospital. This is because research has shown that women with higher
BMI’s at the start of their pregnancy are at higher risk of complications whilst pregnant and when in
labour. Your consultant obstetrician will need to discuss the risks with you and your partner and
develop a specific plan of care for your pregnancy and the birth of your baby.
What conditions may occur more frequently in pregnancy?
The following conditions occur more commonly during pregnancy with increased BMI
Miscarriage
Fetal Abnormalities particularly neural tube defects including spina bifida
Increased blood pressure
Diabetes
Increased rate of induction
Increased rates of operative delivery including caesarean section
Anaesthetic problems
Bleeding after delivery
Thrombosis (blood clots in legs)
Greater rate of admission to special baby/neonatal unit
Why is taking Folic Acid tablets important?
You should consider commencing folate tablets (5 mgs) before pregnancy and continue to 14
weeks as this has been found to reduce the risk of spina bifida. Your GP can prescribe this for you.
After 14 weeks you should change to Healthy Start vitamins (contains Folic, Vits C+D). They are
available at your local health centre and should be taken for the remainder of their pregnancy.
Why is taking Aspirin tablets important?
You may be prescribed low dose Aspirin (75 mgs) daily throughout your pregnancy, if you are
assessed to be at risk of high blood pressure. This will help reduce your risk of developing
preeclampsia during pregnancy.
Advice about your diet is important
You will be offered an appointment to attend the dietician for advice regarding your diet during
pregnancy. This is to support you in healthy eating during the pregnancy which helps both you and
the baby.
What additional tests will you have arranged in pregnancy?

It is important to have detailed scan at 18 – 20 weeks to carefully assess your baby and
ensure normal development. This is often more difficult in women with higher BMI`s and
occasionally complete examination of your baby may not always be possible.

During your pregnancy you may also be at higher risk of gestational (in pregnancy) diabetes
a glucose tolerance test GTT is offered to exclude this and is performed at 28 weeks.

If your BMI is equal to or greater than 35 you will be offered an additional scan at 28 and 34
weeks to assess your baby’s growth as sometimes it can be more difficult to confirm your
baby is gaining weight normally.
Some mothers may be referred to see the Anaesthetist before labour
Because the need for an anaesthetic during delivery may occur more frequently it may be
necessary to see the consultant anaesthetist during the antenatal period to discuss any potential
problems. This will be arranged by your consultant obstetrician.
How is the risk of getting a blood clot in your legs reduced?
The risk of having a blood clot in your legs is increased especially after delivery and you may be
prescribed medication to reduce this risk occurring. This usually involves daily injections and
patients are usually taught to self-administer the injection.
If these injections are required before labour they may prevent the use of an epidural anaesthetic
for pain relief in labour, you can discuss this further with the anaesthetist.
How will my baby be monitored in labour?
Monitoring in labour may be difficult. This may mean that the baby may need to be monitored
using an internal clip which is attached to the baby’s head so that your baby can be monitored
more clearly and safely throughout your labour.
If you have any concerns please contact your midwife
If you have any concerns regarding your pregnancy please contact your midwife who will be happy
to discuss any issue with you or will arrange for you to attend the hospital for a discussion with your
Obstetrician
Important information
Please remember that this leaflet is intended as general information only. It is not definitive. We
aim to make the information as up to date and accurate as possible, but please be warned that
it is always subject to change. Please, therefore, always check specific advice on the
procedure or any concerns you may have with your midwife or doctor.
If you have any queries re any information in this leaflet please contact:
ANC at COCH Tel 01244 365106
Author Mr J McCormack Consultant Obstetrician/Gynaecologist
Revised July 2011