PREGNANCY AND DELIVERY
Almost without exception, female patients with porphyria (of any sort) have normal pregnancies and deliver healthy babies without experiencing acute attacks. However, pregnancy is associated with increased levels of hormones such as progesterone which potentially may aggravate porphyria. Severe attacks during pregnancy are now very rare, and even mild attacks are most uncommon.
Our advice therefore is that patients wishing to have children should embark on pregnancy without fear. It is wise to choose a gynaecologist who is prepared to manage the pregnancy intelligently and who will liaise with a physician interested in porphyria as necessary.
The major risk is in fact that medication unsafe for porphyria may be prescribed inadvertently either during the pregnancy or at the time of delivery. This must be avoided. Where any doubt exists, the gynaecologist should consult us about the safety of any medication he/she wishes to prescribe. Should an attack arise during pregnancy, it should be treated promptly according to our usual protocol. In particular, haem arginate would appear to be safe during pregnancy.
We have encountered only two patients who have experienced acute attacks during, and apparently precipitated by, pregnancy. In one, this was restricted to a single attack in the early phases of each pregnancy. These attacks responded well to standard treatment with haem arginate and pregnancy thereafter was uncomplicated and resulted in a healthy baby. In the second, a patient with AIP, both her pregnancies were complicated by a number of recurrent acute attacks during the second trimester. Each responded well to standard treatment with haem arginate and she was induced at 30-32 weeks in order to forestall further attacks. Both mother and infants are healthy. We must stress that this pattern of attacks during pregnancy is extremely unusual and, even so, was fairly easily and safely managed with a satisfactory outcome.
TESTING CORD BLOOD FOR INHERITANCE OF PORPHYRIA IN THE INFANT
Cord blood can be tested to determine whether the infant has inherited porphyria from a parent. (Though antenatal diagnosis is technically possible, it is not indicated for a relatively benign disorder such as porphyria.) Read Diagnosis of porphyria in infants and children.
DRUG SAFETY IN OBSTETRIC PRACTICE
Selecting a safe antibiotic for a pregnant porphyric is usually simple. Read the page Treating infections in porphyric patients.
Prostaglandins given intravaginally are safe. Oxytocin (Syntocinon®, Pitocin®) is safe. Ergometrine is dangerous and must be avoided, therefore syntocinon/ergometrine combinations must be avoided.
Opiates are safe. Epidural analgesia is safe, preferably using bupivacaine rather than mepivacaine. General anaesthesia requires the selection of agents safe in porphyria and if so, is not a problem.
Beta-adrenergic stimulants, such as hexaprenaline, and atosiban are safe. Dexamethasone, for fetal maturation, is safe.