Prolactinoma The pituitary gland increases in size by 50–70% in pregnancy due to normal lactotroph hyperplasia, which in rare cases causes symptoms in pregnancy The presence of an adenoma, called a prolactinoma, in the pituitary gland will further increase its size and cause symptoms.
This adenoma, or cyst, increases the production of prolactin, which is the hormone that initiates lactation. There are two types of adenoma: Microadenoma: accounts for 90% of cases in pregnancy. They are <10 mm in diameter rarely grow significantly regressing spontaneously.
Macroadenoma: accounts for 10% of cases in pregnancy. They are >10 mm in diameter more likely to expand and cause symptoms of headache and visual disturbance. progress to pituitary apoplexy or diabetes insipidus . With both types of adenoma there is a risk of infertility and treatment is with
dopamine agonists, which cause side-effects of : 1-nausea, vomiting 2- postural hypotension, 3- constipation 4-nasal congestion 5- Raynaud's phenomenon
Pre-conception care ; -management depends upon the size of the adenoma which might involve a trial of discontinuing the dopamine agonist or changing to bromocriptine. - In some cases, surgery might be afempted prior to conception to reduce the bulk size of the adenoma
-Once pregnant, the woman should be referred to a specialist unit as this is a high-risk pregnancy. - Antenatal care, however, can be shared with the community midwife and medical/obstetric team. -At the initial visit the midwife should take particular note of past surgery and current medication when undertaking the woman's history. - At each subsequent visit the woman should be asked about headache and visual symptoms.
-It is the medical team who will determine the type and dose of dopamine agonist and perform monthly visual perimetry to detect early signs of compression on the optic chiasma -If there are indications of adenoma expansion, a magnetic resonance imaging (MRI) scan should be performed urgently and bromocriptine commenced. -In most cases the intrapartum care can be facilitated by the midwife, however if the adenoma is expanding the woman is likely to have a preterm induction of labour. -The obstetric team may advise an elective instrumental birth to avoid a rise in intracranial pressure during the second stage of labour
-In the postnatal period the woman is advised to report any symptoms -In the postnatal period the woman is advised to report any symptoms. An MRI scan might be ordered by the medical team and prolactin levels measured aher 3 weeks, by which time the values should have returned to their pre-pregnancy levels. -Follow-up appointments should be made with the specialist medical team who will evaluate the symptoms when determining the re-commencement of pre-pregnancy treatment with dopamine agonists.
The midwife should consult with the doctor and pharmacist for suitable alternative medication if the woman wishes to breastfeed her baby as dopamine agonists are usually contraindicated. - Furthermore, the woman will require specialist contraception advice as oestrogen contained within the oral contraceptive pill might further increase the size of the adenoma and consequently is contraindicated