Pregnancy: Talking to patients

Last updated: Tuesday, September 27, 2022

Communicating the risk of medicines in pregnancy isn’t a situation you are likely to face often as a foundation pharmacist, but it is important to be prepared. You may be asked to counsel a patient who is planning a pregnancy and needs to start a medicine, or perhaps the patient has conceived whilst taking a medicine for a long-term condition. 

Either situation will demand a careful, tailored explanation of the potential risks to the child and the likely benefits of treating the maternal condition in language the woman can understand. It is important that the woman knows that not treating her medical condition may cause more harm than any potential risk(s) posed by a medicine. For example, epileptic seizures in pregnancy can have significant adverse effects on pregnancy outcome and some patients with depression may experience a deterioration in their condition if not treated.  For patients who are likely to require a medicine throughout their pregnancy and postnatally, it may be appropriate to offer advice about safety whilst breastfeeding too.

If written information is available such as that on the bumps website, then this should be used to supplement your consultation. Remember that manufacturers’ patient information leaflets will usually warn against the use of a medicine in pregnancy, and it may be helpful to provide reassurance on this point during the consultation.

A helpful framework to follow is to explain;
  •          The potential consequences of using a medicine during pregnancy
  •          How likely the woman and her unborn child are to be affected
  •          What can be done to manage any risk(s)

It may be helpful to start by explaining that pregnant women are generally not included in clinical trials of medicines, and so often evidence for a medicine’s safety is limited. You may also like to add that it is sometimes difficult to separate out any effect of the maternal disease state on the unborn child and the medicine itself. Explain the known risks clearly, taking into account the stage of the pregnancy that has been, or will be exposed. For example, if a medicine has been associated with causing a cleft palate, but the woman is now 16 weeks post-conception, which is after the palate has formed, then this will not affect her pregnancy.  For newer medicines there may be unknown risks.

Firstly, offer an estimate of the background risks of adverse pregnancy outcomes in the general population to help the woman put any potential risk(s) from a medicine into context. Sensitively explain that as many as 1 in every 5 pregnancies may end in a miscarriage, and up to 1 in 40 babies are born with a birth defect.

Try to convey whether any potential risk(s) are:

  •       Theoretical – such as with a new folic acid antagonist, for example. Although what we know about other folic acid antagonists such as phenytoin would predict the potential for neural tube defects if early exposure has occurred, evidence for the new medicine is completely lacking.
  •       Uncertain at present – for example if different studies have produced conflicting results, the evidence base is made up of only one or two small studies, or some individual case reports, such as with pregabalin and the risk of CNS anomalies.
  •       Suspected – if multiple studies have produced similar results, such as fluoxetine and cardiovascular defects.
  •       Likely or certain – if a medicine has been confirmed as being responsible for a particular adverse effect (‘a causal association’). For example isotretinoin and CNS and facial abnormalities.

Quantify any risk in absolute rather than relative terms. For example you could say ‘’Fluoxetine  may increase the risk of your baby developing an uncommon lung condition after they are born called persistent pulmonary hypertension. The chance of this problem happening may increase from 1or 2 cases in every 1000 newborn babies, to less than 4 in every 1000" rather than "Fluoxetine may double or triple your risk of…."

Once you have explained the potential consequences and the likelihood of them occurring, it is important to describe how they will be managed to reduce their impact upon your patient’s pregnancy. For example, in a woman planning a pregnancy, her medicines should be optimised to only include essential medicines at the lowest effective doses. In some cases maybe non-drug treatment such as cognitive behavioural therapy for mild depression may be appropriate. Older medicines with more safety data may also be preferred such as methyldopa for hypertension, but this isn’t always the case. Any known teratogens should be changed to safer alternatives such as changing warfarin to enoxaparin for the treatment of a deep vein thrombosis.

In a woman who presents after taking a medicine, consider whether the medicine can be stopped, or if it needs to be continued or swapped to a safer option. Explain whether extra monitoring and investigations may be required.