Wednesday March 25 2009
Food during labour does not affect birth outcome or raise risk of vomiting
Research has found that there is “no risk from eating during labour,” said BBC News. The news report said that eating light food during labour does not affect the duration of labour, or the need for assisted delivery or Caesarean rates. The article said that since the 1940s, women have been advised not to eat during labour to reduce the risk of complications if Caesarean is required, principally due to the risk of breathing food back into the lungs while under a general anaesthetic.
This unique study randomised 2,426 women in labour with their first baby to either eating a light diet during labour, or to drink water only. It found no significant difference between the groups in any of the outcomes assessed, including type of delivery, labour duration, use of analgesia, risk of vomiting, and newborn responsiveness or need for special care.
Although the nature of this study creates some inherent limitations, these findings are valuable to maternity wards where a policy of no-eating during labour is encouraged. Expectant mothers who have lengthy labours will also benefit.
Where did the story come from?
Dr Geraldine O’Sullivan from the Department of Anaesthesia, St Thomas’ Hospital, and colleagues from King’s College London and the Guys’ and St Thomas NHS Foundation Trust, carried out this research.
The study was funded by a grant from the Obstetric Anaesthetists’ Association and the Special Trustees of the St Thomas’ Hospital. One of the authors was also supported by Tommy’s, the baby charity. The study was published in the peer-reviewed British Medical Journal.
What kind of scientific study was this?
This was a randomised controlled trial designed to investigate whether eating during labour has any effect on labour and birth outcomes.
At Guy’s and St Thomas Hospital, between June 2001 and April 2006, researchers recruited 2,426 women who were at the end of their first pregnancy. All women were over 18, non-diabetic, had had an uncomplicated pregnancy, were more than 36 weeks pregnant with a single baby, and were currently in labour with cervical dilation of less than 6cm. Women having induced labour were also included. Women who had medical or pregnancy complications that could increase the risk of operative delivery were excluded, as were those who were in severe pain or intended to use intravenous or intramuscular opioid analgesia during delivery (e.g. pethidine).
After consenting to the study, the women were randomised to either drink only water during labour or to eat a low-fat, low-residue diet (e.g. small regular amounts of bread, biscuits, fruit, vegetables, yoghurt and juice) rather than a set regular meal.
The attending midwife recorded the mother’s age, ethnicity and food eaten in the six hours prior to and during labour. Also recorded were the outcomes of type of delivery (the main outcome assessed), labour duration, use of intravenous drugs to increase contractions, and vomiting. Although women were encouraged to eat or not, depending on which group they were in, all of them were free to eat what they wanted during labour.
No routine antacids were given, and labour care was standard, with all interventions during labour performed as indicated and directed by the clinical expertise of the attending care professionals. Women had access to the use of a birthing pool and could choose to use ‘gas and air’ or epidural anaesthesia.
What were the results of the study?
The average age of women in this study was 29, and about 60% were of white ethnicity. Of the 2,426 women randomised into the study, 99% were included in the analysis (1,219 in the eating group and 1,207 in the water-only group). The two groups were similar in terms of mother’s age, ethnicity, pre-labour food intake, need for intravenous fluids during labour, drugs to enhance contractions, and newborn birth weight.
Of the women allocated to water only, 20% actually consumed food, and of those allocated to the eating group, 29% chose not to eat. For the main outcome assessed, there was no difference in rate of vaginal delivery between the eating group and the water-only group (both 44%). For other outcomes, there was no significant difference between the groups in labour duration, rate of assisted vaginal delivery, rate of Caesarean section, use of analgesia, use of drugs to enhance contractions, rate of vomiting, Apgar assessment scores (of health and responsiveness) in the newborn, or rate of admission to special baby care units.
What interpretations did the researchers draw from these results?
The authors conclude that their study demonstrates that a light diet during labour has no effect on labour and birth outcomes, and neither does it increase the risk of vomiting.
What does the NHS Knowledge Service make of this study?
This is a unique study in that it randomised a large number of women in labour with their first baby to either eat light food during labour, or to drink water only. The study found no significant difference between the groups in any of the labour or birth outcomes assessed.
Due to the nature of this study, there are a few inherent limitations to be considered:
- Although this was a randomised trial, the decision to eat, and how much to eat, was decided by each woman herself. During labour, 20% of the women randomised to only have water ate food, while 29% of those randomised to eat did not. This will have some effect on the accuracy of results.
- The midwives and obstetricians who made decisions about care during labour could not be blinded to the woman’s group allocation, but the researchers say they had “no vested interest in the study”.
- The study only assessed healthy women with their first, single pregnancy. The results cannot be extended to women with medical or pregnancy-related complications that may make the need for special intervention more likely. The results also cannot be applied to women using opioid analgesia during labour (which delays stomach emptying, therefore increasing the risk of vomiting or aspiration).
- The main concern among medical professionals regarding eating during labour is the risk of aspiration (breathing food particles back into the lungs) during general anaesthesia if surgical intervention is required. However, this study is not sufficiently powered to answer this question because the incidence of this is very low.
These findings are of value to the medical profession. Many maternity units have a policy of discouraging eating in case intervention is required, and this study could influence this policy. Expectant mothers will also benefit.