Prescribing in pregnancy

One of the most common but challenging aspects of obstetric medicine is the prescription and management of medications in pregnancy. All medications have risks and benefits, but particularly in pregnancy there are clinical and medico-legal considerations that will influence our prescribing, our counselling and the woman’s decision to use a particular medication.

If I search for medications and pregnancy on my browser, I am recommended a site called ‘Safefetus.com’. Along with advertisements for holidays and clothing, I can enter in the trade name of a medication and on a single page read about the FDA category for that agent, the indications for its use, the fetal risks and the lactation advice. These entries are illustrated with a colourful scatter of pills, a three-dimensional colour embryo photo and a cute baby. A disclaimer at the end states

The information on this website is not intended as a substitute for the advice and care of your doctor or other health-care provider. Always consult your doctor if you have any questions about exposures during pregnancy and lactation, and before you take any medications

But what about that doctor who is the ultimate arbiter of whether you should or should not take that medication during pregnancy and/or breastfeeding? Where do we get unbiased, accurate information? Not from the drug company, which almost invariably states that pregnancy is a contraindication. A number of excellent textbooks and medication databases exist to research individual medications or classes of medication but the data are often scant and limited by methodological issues. Most health care providers rely on the drug categorisation provided by the American FDA, Australian APEC or similar national labelling laws for medications.

In 2014, the FDA amended its regulations, abandoning the pregnancy categories A, B, C, D and X. This followed feedback from stakeholders that the A, B, C, D and X categorisation

lacked clarity, often failed to provide meaningful clinical information about drug exposure during pregnancy and lactation, and did not address the potential maternal and fetal consequences of discontinuing needed maternal drug therapy during pregnancy. They were highly relied upon by health care providers but were often misinterpreted and misused

In their December 2014 publication, they outline a new ruling requiring labelling of all medications with a summary of the risks of using the drug during pregnancy and lactation, a discussion of the data supporting that summary, relevant information about pregnancy testing, contraception and infertility and potential impacts on prescribing for females and males of reproductive potential (https://federalregister.gov/a/2014-28241). The regulation is comprehensive and has clearly been guided by clinicians experienced in the field. The development of these data will be a massive task for the pharmaceutical industry and is likely to highlight the absence of data for so many of our commonly required medications.

In this edition of Obstetric Medicine, Dr Debra Kennedy assesses the literature regarding the teratogenic or other risks of ondansetron in pregnancy. A number of vocal critics have implied that this agent should not be used in the first trimester of pregnancy, ¹ even after previously publishing literature contrary to this point of view. ² For the clinician sitting opposite a desperately ill woman with hyperemesis, the nuances of this research may be difficult to explain. This thorough review of a single agent in common usage serves as a template for the quality of data required before accepting medications into our standard ‘repertoire’.

There are other articles discussing drug therapies including a review by Shields et al. on medication and vaccine use in pregnancy and a case report of unplanned pregnancy on rivaroxaban.

There is also an endocrine theme to this quarter’s issue with case report’s on Cushing’s syndrome, and a review on pre-pregnancy counselling for acromegaly. Valent et al. explore the influence of obesity on perinatal outcomes in pregnancies achieved with assisted reproductive technology in a population-based retrospective cohort study.

This issue also includes an article by Harvey Makadon, ‘Transgender men and pregnancy’, that has been downloaded just under 1000 times, tweeted out via eight channels to a following of 30,245 and has been mentioned by The University Herald, Science 2.0, Science Newsline, Science Daily and Medical News Today. It makes for absolutely fascinating reading and we hope you enjoy it!!