Fat vaginas and shrinking newborns in Japan

When I got pregnant I weighed 53 kilos at 170cm (118 pounds, 5’8); I gained 13 kilos or 28 pounds over my pregnancy. My daughter was born at just 2.6 kilos (5 pounds 11 ounces). By British or US criteria my gain was fine, and indeed I found myself wondering if I should have gained a bit more, judging by my baby’s rather modest size. Yet by Japanese standards I had gained an excessive amount. Welcome to the insane world of the incredible shrinking Japanese pregnancy.

Official guidelines in Japan recommend that women gain 7-12 kilos if they are normal weight, and 9-12 kilos if they are underweight—significantly lower than the guidelines of the UK and US. However, these figures mask the reality that is going on in clinics and hospitals where doctors routinely pressure women to gain even less than the official limits. “My doctor told me I should stop eating all fruit and carbohydrates,” complains one mum (whose weight gain was picture perfect according to the US guidelines). “I was scolded by the nurses every time I went in; they said I wouldn’t be able to push the baby out,” says another. Others reveal stories of doctors telling them they should be losing rather than gaining weight during pregnancy, or informing them that they would get a “fat vagina” unless they drastically restricted their calorie intake. No, I don’t know what a fat vagina looks like either.

What are the trends in newborn weight?

Perhaps part of the anxiety about gaining too much weight comes from the widespread misconception in Japan that average the average newborn is getting heavier. In fact, birthweights did rise through the 1960s and 1970s in Japan, but from about 1980 the trend went into reverse, with birth weights falling by 125g in the past 25 years. It seems that previous decades' anxieties about “babies getting too big” may have lingered on into the present, distorting doctors’ and the public’s perceptions.

To a certain extent it is understandable that Japanese medical authorities became worried by fact that babies and mothers were growing a bit heavier during the 1960s and 1970s. If a woman genuinely does gain too much during pregnancy, it does indeed increase the risk of difficult births, and this may be particularly true for Asian women. Asian women who gain too much are significantly more likely to develop gestational diabetes than other ethnicities. Big babies may be more likely to wreak havoc on an Asian mother’s body, as there is also some evidence that women of Asian ethnicity are more likely to sustain serious perineal tears in childbirth. Nobody is quite sure why—perhaps it is because Asian babies are proportionally larger compared to their relatively small mothers. In most developed/middle income Asian countries, this problem is increasingly being circumvented through very high cesarean rates (40-50% in countries like China and Vietnam). But the Japanese remain emotionally and culturally committed to the idea of natural childbirth; not surprisingly, a “Keep ’em small at all costs” mentality has tended to develop. 

I suppose there is a sort of “sunk-cost fallacy” in such matters—if you have spent the last decade or two telling women to severely restrict their weight, the possibility that this advice may have been harming babies may be too painful to confront. Easier to keep telling yourself that your advice is correct and always has been. It’s not like Japanese healthcare providers are exactly great at accepting questioning at the best of time.

Oh, and it’s very, very hard to get an epidural in Japan, due to a critical shortage of anesthesiologists and the cultural belief that mothers are “supposed” to suffer in childbirth, and this has probably also encouraged doctors and midwives (all of whom will have watched women suffering in long, hard labors) to encourage mothers to keep their bellies and babies small. In fact, a small baby does not always equal an easy birth--I know women who’ve torn badly pushing out five-pounders--but when you are staring down the barrel of a completely unmedicated labor with absolutely no way out of it, you are naturally going to clutch at whatever straws are available to you which might, maybe, just make things a bit easier. Add in standards of beauty which demand insect-like thinness in women even before pregnancy, and you have a perfect storm for extreme weight restriction in pregnant women. 

The consequences

Slowly, however, awareness is growing in Japan about the risks of too little weight gain in pregnancy. Japanese midwives are still heard to express enthusiasm about the idea of keeping fetuses small and then feeding them up after delivery, but as the doctor quoted in the Bloomberg article puts it, “Being born small and growing big is the worst possible scenario for risk of disease." Babies undernourished in the womb and born small may be at elevated risk of problems such as obesity and hypertension later in life,  possibly because such undernourishment sends out signals that cause the fetus's body to prepare for famine conditions in the outside world (an extreme form of this was seen in the babies born after the Dutch Hunger Winter of 1944-45, who have proven to be more prone to problems such as cardiovascular disease as adults).  

A need for balance

It’s not that we need a complete free-for-all either. Most women I know who gave birth in the UK report that they were never weighed or given any advice on weight gain, a fact which is almost certainly connected with the fact that the percentage of deliveries assisted by forceps has doubled over the last 10 years as mothers start their pregnancies heavier, gain more and have bigger babies. It’s completely reasonable for healthcare providers to be honest with patients about the fact that excessive weight gain increases the risk of difficult births, not to mention the fact that (in my own experience) women who gain huge amounts are more likely to feel uncomfortable during pregnancy and have an difficult psychological transition to motherhood afterwards. 

Nevertheless, there is mounting evidence that excessively strict weight guidelines in Japan are putting the health of babies at risk, and making pregnancy--which is supposed to be one of the happiest times in a mother's life--into a period of unnecessary anxiety, guilt and embarrassment for women. While a certain amount of caution regarding weight gain is probably advisable for Japanese women in particular, given ethnic factors relating to gestational diabetes and the problem of perineal trauma, the advice to restrict weight in pregnancy seems to have become unnecessarily extreme and to have taken on a life of its own. For mothers' and babies' sake, it's time for Japanese healthcare providers to swallow their pride and review their policies on gestational weight gain.

Further reading:

Diets by Pregnant Women Spur More Underweight Babies in Japan (Bloomberg)

Babies born in Japan getting smaller (Asahi)

Problems of Underweight in Young Females and Pregnant Women in Japan