Antidepressant use in pregnancy needs further research

Dr Duncan Shrewsbury 
Dr Ben Janaway

II  DEC 18 2016

New research suggests a link between antidepressant use and birth defects. The study investigated a potential increased risk of heart disease, anomaly or still birth.  Although a small increase in risk of heart disease was found, statistical analysis of stillbirth and other problems could not exclude ‘chance’ as contributory to the result, meaning strict conclusions cannot be drawn. Furthermore, the ‘composite’ nature of data collected leaves many  questions. Without more research, decision making around pregnancy is difficult and any conclusions should be made with caution.

This has not stopped potentially misleading tabloid headlines warning against use of such medications.

Since pregnancy and depression is common, the findings require further investigation. Primarily, the nature of relationship between SSRI use and CHD. In the meantime, its best to ignore sensationalism and talk to your GP. As always, healthy scepticism of headlines is advised.

Evaluating risk in pregnancy

There are many medications that can cross the placenta, from mum’s bloodstream to baby’s. These include antidepressants. Some of these medications will have very little impact on baby’s development, and others more.  Study of medication effects on children is notoriously difficult, where the individual risk of an effect by a specific medication is hard to gauge. 

These relationships are often incredibly complex, but are seemingly simplified by associating X (exposure to medicine) with Y (a pattern of anomalies). The national advice centres that doctors consult regarding medicines in pregnancy collects information from research done all over the world. The conclusions referred to by media are yet to be updated in light other research, meaning its overall significance is unclear.

Depression in pregnancy

Depression is a potentially serious mental health condition that affects approximately 1 in 5 people during their lifetime. It is characterised by pervasive low mood, inability to find enjoyment, loss of motivation, and disturbances in concentration, sleep and appetite. Experience varies, and no two journeys will be the same.

During pregnancy, depression is associated with increased risk to mum (both complications of pregnancy are more common, as well as risks such as self-harm and suicide.) These risks are existing with or without treatment. The aim of treatment in depression is to relieve symptoms and improve quality of life.

Current opinion

Any woman who is planning a pregnancy, or who is pregnant, who experiences any of the symptoms associated with depression ought to speak to their GP. After taking a history, and evaluating risk, a conversation about potential treatment options, and the risks associated with them ought to be explored openly.

If the risk to mum is greater if her depression is untreated, then treatment options (including SSRI) should be considered. Suddenly stopping antidepressant medication can have complicating consequences, as can many over-the-counter alternatives. Should a mum-to-be wish to explore alternatives, or to consider stopping any antidepressant medication  should seek medical advice.
 
A note on correlation and causation

In research, there is a fundamental distinction between the terms ‘correlation’ and ‘causation’. A correlation denotes a statistical relationship between two variables, but does not explain the nature of that relationship.  In simple terms,  X may be linked to Y, but we cannot say that X causes Y or vice versa.  A commonly used example is the relationship between prevalence of ‘storks’ and ‘new births’.

We all know the story of the baby-delivering stork. Numbers of storks and babies grow each year. A statistical analysis of the number of storks and number of human births over years suggests that more storks means more babies. You could incorrectly infer that therefore, storks bring babies. Clearly we know this not to be true. This is one example of how findings can be ‘correlative’ but not ‘causative’. 
 
Any opinions above are the author's alone and may not represent those of the NHS or Mind and Medicine. Any comment is based on the best available evidence at the time of writing.  All data is based on externally validated studies unless expressed otherwise. Novel data is representative of sample surveyed. Online recommendation is no substitute for seeing your own doctor and should not be taken as medical advice.
 
Sources

1. Parry (2016) The Sun (5th Dec) Drug Dangers: mums-to-be who take common anti-depressants are at greater risk of birth defects and still birth. https://www.thesun.co.uk/living/2331342/mums-to-be-who-take-common-anti-depressants-are-at-greater-risk-of-birth-defects-and-stillbirth/
2. Jordan S, Morris JK, Davies GI, Tucker D, Thayer DS, Lutejin JM, Morgan M, Garne E, Hansen AV, Klugensoyr K, Engeland A, Boyle B, Dolk H. (2016) Selective serotonin reuptake inhibitor (SSRI) antidepressants in pregnancy and congenital anomalies: analysis of linked databases in Wales, Norway and Funen, Denmark. PLoS One, 1, 11(12): e0165122.
3. Bolton J, Bisson H, Guthrie E, and Wood S. (2011) Depression: key facts. Royal College of Psychiatrists. http://www.rcpsych.ac.uk/healthadvice/problemsdisorders/depressionkeyfacts.aspx
4. National Institute of Health and Care Excellence (NICE). (2015) Depression – antenatal and postnatal complications. https://cks.nice.org.uk/depression-antenatal-and-postnatal#!backgroundsub:3
5. UK Teratology Information Service: http://www.uktis.org/
6. UKTIS. (2016) Use of selective serotonin reuptake inhibitors in pregnancy: http://www.medicinesinpregnancy.org/bumps/monographs/USE-OF-SELECTIVE-SEROTONIN-REUPTAKE-INHIBITORS-IN-PREGNANCY/
7. National Institute of Health and Care Excellence (NICE). (2015) Depression – antenatal and postnatal: Pregnant women on antidepressants. https://cks.nice.org.uk/depression-antenatal-and-postnatal#!scenario
http://robertmatthews.org/wp-content/uploads/2016/03/RM-storks-paper.pdf