From the Guidelines
Routine prolactin level checks are not necessary during normal pregnancy. Prolactin naturally increases during pregnancy as it prepares the breasts for milk production, rising to modest increases compared to pre-pregnancy levels 1. This physiologic increase is expected and doesn't require monitoring in uncomplicated pregnancies. Some key points to consider include:
- Prolactin remains elevated in breastfeeding women, and breastfeeding bouts trigger acute increases in both prolactin and oxytocin, while estradiol and progesterone levels are suppressed during lactation amenorrhea 1.
- Most hormones return to pre-pregnancy levels within one to two weeks, but prolactin levels can remain elevated during lactation 1. However, prolactin testing may be appropriate in specific situations, such as when a woman has a known pituitary tumor (prolactinoma) before pregnancy, develops new visual disturbances or severe headaches during pregnancy, or shows signs of abnormal lactation patterns. Key considerations for managing prolactin levels during pregnancy include:
- Consultation with an endocrinologist for women with pre-existing prolactinomas
- Potential continued bromocriptine therapy during pregnancy, especially with larger tumors
- Monitoring for signs of abnormal lactation patterns or other complications related to elevated prolactin levels.
From the Research
Prolactin Levels During Pregnancy
- Prolactin levels can vary significantly during pregnancy, with normal levels ranging from 6 ng/ml during early pregnancy to 210 ng/ml near term 2.
- It is not entirely necessary to check prolactin levels during pregnancy, as plasma prolactin levels do not seem to be a valuable guide to maternal or fetal well-being 2.
- However, in cases of suspected prolactin-secreting pituitary adenoma, it is essential to closely monitor the patient during pregnancy for clinical symptoms of enlargement of the tumor, including periodic visual field examinations 3.
Management of Hyperprolactinemia During Pregnancy
- Dopamine agonists, such as bromocriptine, can be used to treat hyperprolactinemia during pregnancy, and their use is considered safe in the event of clinically relevant tumor expansion 4.
- Pregnancy itself can lead to a decrease in prolactin levels, with a "normalization" rate of 17% observed in one study 5.
- The management of hyperprolactinemia during pregnancy should be individualized, taking into account the patient's specific condition and medical history 6.
Key Considerations
- Women with suspected intrasellar prolactin-secreting pituitary adenoma should be allowed to conceive and give birth without previous surgical intervention, but should be closely followed during pregnancy for any signs of tumor enlargement 3.
- The risks of pregnancy in women with prolactinomas have probably been overstated, and dopamine agonists can be used as primary treatment for women with prolactinomas of all sizes 4.