"One in four mothers-to-be have mental health issues before birth," is today's headline from the Mail Online – leading us to suspect that it misunderstood the point of the study.
The fact that 1 in 4 pregnant women have mental health issues isn't that surprising given previous research has shown that 1 in 6 of all adults in the UK are affected by mental health issues at any given time. A rise above this average could be explained by the extra stresses of being pregnant.
But the study in question wasn't a survey of mental health problems in pregnant women. The researchers actually wanted to see how accurate a simple screening tool for depression was in correctly identifying women with mental health issues.
The "Whooley questions" tool consists of just 2 questions:
After asking these initial questions, the researchers then used more detailed questionnaires for diagnosing mental health problems to see if the results matched those from the Whooley questions.
The Whooley questions were fairly good at identifying people with issues – about two thirds who responded "yes" had some diagnosable mental health problem. However, it still missed about a quarter of those who had problems so may not be reliable enough to be used as a sole screening tool at this stage.
Nevertheless, this study addressed an important issue: that every effort should be made by health professionals to identify women suspected of having a mental health problem during early pregnancy.
Read more advice about mental health during pregnancy.
The study was carried out by researchers from King's College London and the University of Melbourne, Australia, and was funded by the National Institute for Health Research. It was published in the peer-reviewed British Journal of Psychiatry. At the time of writing, the paper wasn't yet available online.
Both the Mail Online and BBC News seemed to miss the point of the study. It was not a general survey of mental health problems in pregnant women. Rather, it discussed whether different depression screening tools are detailed and accurate enough to detect mental health problems in this population.
The Mail Online also stated "problems are being missed because of incorrect belief that pregnant women have a feel-good 'glow'." This notion wasn't addressed by the research and appears to be pure speculation on the part of the Mail.
This was a cross-sectional survey of women responding to depression screening questions during early pregnancy.
The study looked at how accurate the Whooley screening questions and the standard-use Edinburgh Postnatal Depression Scale (EPDS) were at detecting mental health disorders, compared with the standard Structured Clinical Interview for DSM-IV (SCID) diagnostic criteria.
The Whooley questions were created by Professor Mary Whooley of the University of California and weren't specifically designed for use in pregnancy. However, the researchers wanted to see if they could be used as a screening tool for this purpose.
Because of their brevity, the Whooley questions are regarded as helpful by many, as they can be used by health professionals without formal psychiatric qualifications – such as GPs, nurses and midwives – as an initial step towards diagnosis.
This sort of study, where participants are assessed using both the tests being evaluated as well as the standard diagnostic tools, is a good way of investigating the diagnostic accuracy of the test being investigated.
Pregnant women over the age of 16 were recruited when they attended their first antenatal appointment in south-east London between November 10 2014 and June 30 2016. During this appointment, women were routinely asked the Whooley questions:
All women responding positively to these questions (answering yes to one or both) and a random sample of women responding negatively (answering no to both) were invited to participate in the study.
They were invited to attend an interview a maximum of 3 weeks from their initial antenatal appointment, where the Whooley questions had been asked. The short time interval was to ensure the participants would not have received any form of treatment that could have altered the accuracy of the initial diagnosis.
At the interview, the following assessment tools for depression were used:
The researchers looked at the accuracy of both the Whooley questions and the EPDS for detecting mental health disorders.
Of 9,963 women who responded to the Whooley questionnaire, 545 were invited to participate in the study – 258 who had responded negatively and 287 positively.
Women who responded positively to the Whooley questions were more likely to:
Of the positive respondents, 66% had a mental health disorder and 45% had depression. Of those responding negatively, 22% had a mental health disorder and 7% had depression.
This means that using only the Whooley questions would have missed some women with a condition.
The EPDS performed slightly better than the Whooley questions.
The researchers said: "The endorsement of Whooley questions in pregnancy indicates the need for a clinical assessment of diagnosis and could be implemented when maternity professionals have been appropriately trained on how to ask the questions sensitively, in settings where a clear referral and care pathway is available."
This study addressed the important issue of mental health problems during pregnancy, which can be associated with poor outcomes for women, the pregnancy and the child if the issues are not identified and treated. Early identification of antenatal mental disorders in pregnancy is essential to ensure the woman receives the support she needs and to prevent complications.
This study made a good attempt at assessing the accuracy of the Whooley questions, asked by midwives at routine maternity contact. It also benefited from assessing women using standard diagnostic questionnaires.
However, there were some key limitations.
The best type of diagnostic-accuracy study looks at all the women who screened positive and all the women who screened negative, and retests all of them using the standard tools. This study only selected a random 10% sample of those who responded negatively to the Whooley questions. The results showed that, within this sample, a quarter turned out to have a mental health condition. So by testing only a sample of those who responded negatively, the accuracy of the Whooley questions may have been overestimated.
Furthermore, many of those eligible to participate – the random sample of women who responded negatively to the Whooley questions and all the women who responded positively – did not take part in the study and complete the standard questionnaires, for various reasons.
Had all the respondents to the Whooley questions been tested, the researchers would have a better indication of the accuracy of the Whooley questions, their suitability for use as a screening tool and a bigger sample to inform prevalence.
For the results of this study to be more credible, it would need to be repeated with a larger sample of women in other parts of the UK and include all women who responded yes or no to the initial screening questions.
However, these limitations don't alter the fact that depression and other mental health problems during pregnancy can have profound effects on both the mother and the family. It's essential that health services detect them early and provide appropriate support.