Surgery during pregnancy

There is ample published evidence about safe surgery during preg­nancy. However, oncological surgery is less well described. The im­portant outcome measures that need to be considered include:

• optimal oncological and surgical outcome

• maternal well-being

• fetal well-being.

Optimal oncological and surgical outcome

Most oncological surgery during pregnancy is outside the abdom­inal cavity and can usually be performed without serious risk to the developing child. Laparotomy for intra-abdominal tumours is com­plicated by an enlarged uterus and access to the pouch of Douglas may be impossible in advanced pregnancy. The use of laparoscopy during pregnancy has become more accepted in recent times with a lot of experience being gained in many centres around the world. The precautions during laparoscopic surgery include open laparo­scopic entry and using lower intra-abdominal pressures of less than 15 mmHg. Preferably the surgeon performing the procedure should be a skilled laparoscopic surgeon with experience in operating on pregnant patients.

Maternal well-being

Anaesthetic considerations for pregnant patients are well known. Important changes in respiratory function mean that preoxygenation is absolutely essential. Doses for anaesthetic agents may need to be adjusted for the metabolic state of pregnant physiology. Other considerations include a high risk for thrombo­embolic events during pregnancy and in cancer cases, which neces­sitate the use of prophylaxis in the form of low- molecular-weight or unfractionated heparin.

Fetal well-being

Fetal oxygen supply is dependent on effective maternal ventila­tion and even short periods of maternal hypoventilation can lead to fetal distress. In more advanced pregnancies and long surgical procedures, it is prudent to monitor the fetus with continuous cardiotocography (CTG) in theatre. In first-trimester pregnan­cies, it is adequate to check the fetal heart with fetal Doppler pre- operatively and postoperatively. Preventing premature labour or miscarriage may be achieved by administering non-steroidal anti-inflammatory drugs (NSAIDs) but it needs to be kept in mind that in the third trimester, NSAIDs may lead to the closing of the ductus arteriosus (7). Tocolytic agents are generally used perioperatively to prevent preterm labour. Postoperative care is not dissimilar from non-pregnant patients; however, consider­ations for safe analgesia include omitting NSAIDs in the third tri­mester. Antiemetics are essential due to an already increased risk for nausea and vomiting.