OBESITY IN PREGNANCY

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(Date of issue: May 2011, Version: 1)

This is a UKTIS monograph for use by health care professionals. For case-specific advice please contact UKTIS on 0344 892 0909. To report an exposure please download and complete a pregnancy reporting form. Please encourage all women to complete an online reporting form.

Summary

Obesity is an excessive accumulation of body fat which can adversely affect health and is generally associated with a body mass index (BMI) ≥30. 

Pre-pregnancy obesity is associated with an increased risk of neural tube defects (NTDs), heart defects, cleft palate ± cleft lip, anorectal atresia, hydrocephaly and limb reduction abnormalities.

Obesity significantly increases the risk of gestational diabetes, hypertension, pre-eclampsia, fetal macrosomia, birth trauma, protracted labour, operative vaginal delivery, shoulder dystocia, caesarean section delivery, and the postpartum complications of haemorrhage, thrombosis, and infection.  In cases of caesarean delivery, obese women have an increased risk of significant operative morbidity and death.

Appropriate advice and support in pregnancy is required.  Ideally, obese women should reach a normal body weight before pregnancy, but weight loss is challenging and methods to achieve it must be balanced against their risks.  Weight loss during pregnancy is not recommended, although weight gain during pregnancy in obese women should not be greater than 9kgs.

Due to the increased risks of NTDs, limb and cardiac defects, obese women are advised to take folic acid supplementation of 5mg daily.  In addition, women with pregnancy obesity are advised to take a vitamin D supplementation of 10mcg per day to reduce the risk of the infant developing rickets. 

Note: This document has been archived and will not be routinely updated. If up-to-date information is required please contact UKTIS.

This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from TOXBASE.org or UKTIS.org to be sure you are using the most up-to-date version.

This is a summary of the full UKTIS monograph for health care professionals and should not be used in isolation. The full UKTIS monograph and access to any hyperlinked related documents is available to health care professionals at www.toxbase.org.

If you have a patient with exposure to a drug or chemical and require assistance in making a patient-specific risk assessment, please telephone UKTIS on 0344 892 0909 to discuss the case with a teratology specialist.

If you would like to report a pregnancy to UKTIS please click here to download our pregnancy reporting form. Please encourage all women to complete an online reporting form.

Disclaimer: Every effort has been made to ensure that this monograph was accurate and up-to-date at the time of writing, however it cannot cover every eventuality and the information providers cannot be held responsible for any adverse outcomes of the measures recommended. The final decision regarding which treatment is used for an individual patient remains the clinical responsibility of the prescriber. This material may be freely reproduced for education and not for profit purposes within the UK National Health Service, however no linking to this website or reproduction by or for commercial organisations is permitted without the express written permission of this service. This document is regularly reviewed and updated. Only use UKTIS monographs downloaded directly from TOXBASE.org or UKTIS.org to ensure you are using the most up-to-date version.