Questioning the recent advice about CMV in pregnancy

These days, guilt seems intrinsic to parenthood. And as many mothers will know, health professionals seem ever ready to stoke up guilt with their advice. Don’t smoke

The new guideline

So, what are women now urged to do to avoid CMV? To quote from the new RANZCOG guideline:

Do not share food, drinks, or utensils used by children (under the age of three years)

Do not put a child’s dummy/soother in your mouth.

Avoid contact with saliva when kissing a child (“kiss on the forehead not on the lips”)

Thoroughly wash your hands with soap and water for 15-20 seconds, especially after changing nappies, feeding a young child, or wiping a young child’s nose or saliva.

Clean toys, countertops, and other surfaces that come into contact with children’s urine or saliva.

Does that sound easy? If you think so, double-check with a friend who has young children. From my spot poll of parents, many feel that careful adherence to these rules would be unmanageable. Homes are not hospitals; interacting with our loved ones is not a sterile procedure.

I can’t help but feel that we are setting mothers up to fail by introducing these standards and thereby compounding the guilt they carry. Early parenthood is a risky time of life for mental health issues like depression.

Read more: ‘I didn’t know who I was anymore’ – myths vs realities of early parenthood.

If we are to make new mothers feel guilty about such fundamental human interactions as sharing meals and kissing, won’t we intensify their stress at this vulnerable time?

If mothers feel they must respond to a joyful kiss from their toddler not with reciprocation but with admonishment – “not on the lips, darling, only the cheek” – mightn’t this affect their bonding with their child?

Homes aren’t hospitals, and interacting with kids will always be messy. Halfpoint/Shutterstock

What about the evidence?

The stresses above might be worth enduring if there was good evidence that these behavioral changes made a difference. But I’m unconvinced.

According to researchers who recently reviewed the world’s evidence, only three studies are looking at whether hygiene and behavior recommendations can prevent congenital CMV.

The largest was a study comparing how often women in a maternity hospital picked up CMV before and after hygiene advice. Infected proportions changed from 0.42% before the direction to 0.19% afterward.

But “before-after” studies aren’t a reliable guide to cause-and-effect. The most susceptible women may just have caught CMV earlier, leaving only women at less risk for the second phase of the study.

The best study design to establish cause-and-effect is a “randomised controlled trial,”” in which women are randomly allocated to receive hygiene advice or not. There are two such trials.

One was tiny and found no significant difference between the non-pregnant women who were randomized to hygiene advice. Separately, they followed 14 pregnant women who were given hygiene advice, who all remained uninfected. Still, they weren’t randomized – there was no group of pregnant women without such advice to compare to.

The bigger trial randomized 166 non-immune mothers of young children to either receive hygiene advice or not. Despite providing free soap and gloves to the hygiene group and visiting these women every three months to monitor their behavior, exactly 7.8% of women in each group caught CMV – no difference.

The guidelines advise against routine testing for CMV. Zholobov Vadim/Shutterstock

Pregnant women who knew from special tests that their child was shedding CMV had a low infection rate – presumably, this test result was a motivator for behavior change. But this is evidence of the effect of testing, not of giving hygiene advice.

So, I can’t see convincing evidence that routine hygiene advice works – not without the addition of tests of mothers’ immunity and children’s viral status. Doing such tests is not part of the new RANZCOG guideline – indeed, it explicitly advises against routine testing.

So what should we do?

I’m really torn on this issue. My heart aches for the families of children severely affected by congenital CMV. They must carry a heavy burden of guilt, wondering if they could have prevented the infection. I understand their motivation to avoid further harm. I share their desire for more research on CMV prevention.

Read more: Explainer: what’s cytomegalovirus, and why do pregnant women need to know about it?

But I am saddened, too, by the prospect of a generation of women taught to see their toddlers as dangerous, all in the name of preventive measures that remain unproven.

What do you think? Perhaps we need a community conversation about balancing the trade-offs here: the uncertain prevention of serious but uncommon outcomes versus widespread anxiety about normal family behaviors.

Meanwhile, it’s time for me to close my laptop, share a meal with my family, and, later, kiss my kids goodnight.

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