No good evidence for drugs, like antacids, in normal labour to reduce the small chance of inhaling some stomach contents if general anaesthesia is required.
Caregivers are often concerned that some woman in normal labour may go on to have a general anaesthetic, either for a caesarean section in labour, or to remove the placenta after birth should it be retained. The concern arises because there is a very small risk that the woman might regurgitate and possibly inhale some of the stomach contents into the lungs (gastric aspiration or Mendelsohn's syndrome) during the general anaesthetic. This can cause severe lung and breathing problems, especially if the stomach contents are acid (low pH), and extremely rarely (one in a million) a woman may die from an anaesthetic problem. Giving drugs to reduce the volume of the stomach contents, or to make them less acid may help to reduce the problem. The review of trials looked to see whether giving such drugs routinely to all women in normal labour was effective. The review identified three trials involving 2465 women but none assessed gastric aspiration, probably because it is a very rare event. Instead the trials all assessed the incidence of vomiting, although there is no proven link between vomiting in labour and gastric aspiration during general anaesthesia. The review found some limited evidence that 1) drugs like antacids may reduce the chance of vomiting in labour, 2) H2 receptor antagonist drugs (like ranitidine) appeared to have a similar impact on outcomes as antacids and 3) dopamine antagonists (like metoclopramide) may reduce the chance on vomiting in labour when given alongside pethidine. Overall, there was no evidence that any of these drugs reduced the incidence of gastric aspiration or Mendelsohn's syndrome.