Severe morning sickness, known as hyperemesis gravidarum (HG), is a debilitating condition that affects around 1-2 percent of pregnant women in the UK. Far more serious than 'normal' morning sickness, it is one of the most common reasons for hospitalization during pregnancy and can continue right up until birth. Women can be bed-bound for weeks on end, suffer dehydration and weight loss and are often unable to work or care for other children they have.

The study, by researchers from Imperial College London and Imperial College Healthcare NHS Trust, found that nearly half of women with HG suffered antenatal depression and nearly 30 percent had postnatal depression. In women without the condition, just six percent experienced antenatal depression and seven percent suffered postnatal depression. The findings are published today in BMJ Open.

Dr. Nicola Mitchell-Jones, specialist registrar in obstetrics and gynecology and lead author of the study, believes the psychological impact of the condition is not taken seriously enough by both healthcare professionals and the wider public.

"Our study shows that women with HG are around eight times more likely to suffer antenatal depression and four times more likely to have postnatal depression," she says. "Some women in the study even had thoughts of self-harm whilst suffering HG. These figures are shocking and should be reflected in the treatment women receive. We need to do much more than simply treat the physical symptoms of HG; assessment for mental health support should also be routine for any woman with the condition."

The study recruited 214 women across three London hospitals—Chelsea and Westminster Hospital NHS Foundation Trust, Queen Charlotte's and Chelsea Hospital and St Mary's Hospital (both part of Imperial College Healthcare NHS Trust)—in the first trimester of pregnancy.

Half were recruited on admission to hospital with symptoms of HG. A similar size control group, without significant nausea or vomiting, were recruited through a midwifery-led antenatal clinic. None of the study participants had been treated for mental health conditions in the last year. The women were assessed for their psychological wellbeing in the first trimester of pregnancy and six weeks after the birth.

Of the women with HG, 49 percent experienced depression during pregnancy compared to just six percent in the control group. Just seven percent of the control group had postnatal depression, compared to 29 percent in the group with HG. Half of the women with HG were forced to take four or more weeks off work during or after pregnancy.

Although the study found no direct link between HG and maternal-infant bonding, other research has shown that depression can have a negative effect on this bond. Sadly, eight women with HG recruited to the study terminated their pregnancies, despite originally expressing a desire to keep the baby.

"Although we can't say that HG was the main reason for those decisions, it may certainly have played a role which is heart-breaking," said Dr. Mitchell-Jones, who herself suffered from HG during her first pregnancy in 2018.

"I was in and out of hospital, spent nearly six months in bed—but I was lucky enough to have a supportive employer and family," she recalled. "Many women can't afford that amount of time off work or are stay-at-home mums with young children to care for. Too often their partners, relatives or work colleagues are not providing the support they need because they fail to understand the severity of what these women are going through. We need to educate them, as well as healthcare professionals."

Dr. Mitchell-Jones hopes that her findings can help to improve understanding of HG and change clinical guidelines on how women with the condition are treated, to include a psychological screening and referral to specialist mental health where required.