Menarché and Low Fertility

Earlier this morning I read this intriguing paper by US researchers Robert Drago & Amy Varner. The title of the paper is “Fertility and Work in the United States: A Policy Perspective” and it addresses the important issues of gender equality and the historical trend towards declining fertility in the United States. Now while I was thinking of how to write a post on this general topic I wandered over to Brad Delong’s blog and found he had this highly relevant post entitled Menarché vs Monarchy.

OK, what’s this all about.

Well………. before we can go much further we need to touch on one of the important underlying reasons for the really low low-fertility levels (below 1.5 TFRs) that we can now find in many OECD countries: the so-called tempo effect. (Rather than belabouring the reader too much here, I have just put up a post on my own blog which has a little more detail and argument on the tempo effect and it’s consequences, and you can also see it identified in slide 18 in this presentation, which is dealt with in this post and its comments).

Basically fertility hits extremely low levels due to a displacement upwards in the age of having children. The reasons for this are various (a consumer society would be one of them, need to earn and save enough to purchase a home might be another) and rising education needs for women in an information economy would certainly be another. The problem is, in order to improve our fertility we need to address this trend, and to try, if possible, to encourage women to have children at a younger age. This is entirely amenable to being argued in policy terms on a social interest basis, but the really, really interesting point that Drago and Varner stress is that this is also in the interest of the woman who wants to have children.

If you like ppt presentations demographer Tomás Sobotka has a very interesting presentation about these sort of issues here.

Most of the studies indicate that women on average wish to have two children. Unfortunately, like many wishes, this one does’t convert itself into reality. The big question is why not?

Well one of the issues is fertility – in the biological sense of reproductivity. There is a window of fertile opportunity, with a peak age of fertility, and past this age things get more and more difficult. Without apologies I quote Drago and Varner at length, since I think this issue is generally poorly understood:

It is well known that, over long periods of time, as a nation becomes more affluent, average family size shrinks due to a reduction in rates of childbearing….What is less well known and little studied is the related phenomenon of delayed childbearing. That is, the reductions in fertility just mentioned have occurred in conjunction with a more recent upward shift in the ages at which women bear children. The implications of delayed childbearing are more complex. On the one hand, recent medical advances provide many women with the opportunity to ‘sequence’, and achieve career success prior to the raising of children. For many career women in earlier times, this option was not available and so they were often forced to remain childless in order to stay on a career track. On the other hand, the risks associated with delayed childbearing are not, in our opinion, widely known. We document those risks below. If women and men were aware of the risks surrounding attempts to delay childbearing, it is possible that many would seek to bear children at an earlier age.”

We consider three sets of medical issues related to delayed childbearing below: risks to the mother, risks to the child, and infertility treatments. The latter are not strictly associated with delayed childbearing, although the risk of infertility rises with the age of the prospective mother, leading us to cover the issue here…..There are various maternal risks associated with childbearing. However, as the prospective mother’s age increases, there is a dramatic increase in the likelihood of childbearing complications…..First, the probability of carrying a child to term is significantly reduced after the age of 35…..There are several fetal risks associated with advanced maternal age. In a study of 379 mature prospective mothers, age 35 years and older, in comparison to a control group of 379 prospective mothers, age 20 to 30, there were five stillbirths in the mature age group and none in the younger age group….After a woman’s mid 20s there is a decline in fertility, with dramatic changes during a woman’s 30s and 40s….

“Even a cursory glance at the information provided above would be disturbing for young people considering any delay in childbearing. It is not our purpose to scare people into earlier childbearing with this information, but rather to help individuals make informed decisions. More disturbing to us is that among the many reasons why women and men may avoid facing these facts is the possibility that the choice of children at a younger age is inconsistent with the current structure of careers. To the extent this argument is true, both public and private policies require rethinking and restructuring.”

So bottom line, here is an issue we can do something about. Policy could make an impact. Wolfgang Lutz has suggested that we try informing women of the risks involved in postponement, and also make changes in our education system to enable flexibility between being a mom, and say, postgraduate study, or other kinds of career enhancing activities which could be easily combined with the early months and years of parenthood. Housing policy would be another area which could be scrutinised. The interesting thing is that these are pro-natal measures which may be effective, but which are not intrusive, since they help people do something they want to do, and don’t try to push them into doing something they otherwise wouldn’t do.

So, finally, what is the point about menarché. Well Brad’s post is about a paper from David Weil, “Accounting for the Effect of Health on Economic Growth“. As the post Brad links to explains “According to David Weil, in South Korea, the average age (of menarché) dropped from 16.8 to 12.7 between 1958 and 1998.” On David Weil’s account healthy eating leads to increased biological fertility (or fecundity), and in this way diet and living standards form part of our reproductive history.

As I point out to Brad in the comments section this work on health and reproduction also shows up some of the cruder applications of Malthusianism among economists. The positive checks have a biological element connected with female reproduction – or should these be nature’s preventive checks. Whichever way you look at it there is a positive feedback/negative feedback process as better diet improves fertility (or fecundity in the biological sense) and this may also then be associated with better economic prospects encouraging an increased rate of new home/family formation at a younger age. (Think UK pre industrial revolution from end 16th century). Also being more fertile, the gap between the birth of each child will be reduced. During the Malthusian, or pre-demographic transition, regime the whole thing kicks down again as the population grows beyond a critical point . In reality I doubt the menarché age is so important here, as most societies have pretty systematic rules governing marriage and family formation. But where it really does get interesting is in the case of Korea, since this blog post about a substantial drop in age of first menstruation is accompanied by news that S Korea is just about to start an active pro-natal campaign to try and offset the drop in the birth rate. Now the interesting question would be, is there any connection? I really am not qualified to reach a conclusion, but given everything I have outlined in the earlier part of the post, the correlation does just jump out of the page: the drop in menarché age means the age-fertility bell curve moving to the left, while the age at childbirth distribution curve moves to the right. There is a mis-match here somewhere.

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About Edward Hugh

Edward 'the bonobo is a Catalan economist of British extraction. After being born, brought-up and educated in the United Kingdom, Edward subsequently settled in Barcelona where he has now lived for over 15 years. As a consequence Edward considers himself to be "Catalan by adoption". He has also to some extent been "adopted by Catalonia", since throughout the current economic crisis he has been a constant voice on TV, radio and in the press arguing in favor of the need for some kind of internal devaluation if Spain wants to stay inside the Euro. By inclination he is a macro economist, but his obsession with trying to understand the economic impact of demographic changes has often taken him far from home, off and away from the more tranquil and placid pastures of the dismal science, into the bracken and thicket of demography, anthropology, biology, sociology and systems theory. All of which has lead him to ask himself whether Thomas Wolfe was not in fact right when he asserted that the fact of the matter is "you can never go home again".

15 thoughts on “Menarché and Low Fertility

  1. “declining fertility in the US”

    Hate to quibble but fertility rates in the US are not declining and have remained at around 2 for a while, according to a newly released report, even accounting for immigration.

  2. Hi Rupert

    And don’t worry it isn’t a quibble, I think the US picture is a complex one, essentially related to huge immigration:

    The basic issue is the same though, the migrant mothers have children much younger, so this brings the age at first child back down again post 1970’s. It is of course coming down again as the second generation pass through the demographic transition filter. I have to dash now, but I’ll try and do a bit more on this later.

    Also, it might surprise you to findme quoting CIS – who are basically anti-immigration and complaining, since I favour immigration. I can’t fault the data though, but I’d be interested to see if you could pick any holes in it.

    Thanks for the prb link by the way. I haven’t had time to go through their 2005 report yet. I will do, and will post in due course.

  3. The problem I have with many pro-natal policies is that they seem to not recognize the reasons why people have children later or not at all.

    In many ways, having children is a huge hit on your earning potential. You will be out of work for at least a while, you will get no support while you are working and caring for your child, and you will forever be doubted as a performer or as committed to a company because you dared to have children. Of course, most of these hit women especially. There was one study in the US that showed that having a child meant a reduction in lifetime earnings of $1 million.

    There are many structural issues in European countries that contribute or alleviate this problem. For example, in Germany, kids go home for lunch, so mothers are expected to give them lunch at home, meaning they can’t work full time. In fact, child support declined drastically after German reunification in the East, and that may partially explain the collapse in births there. In France, there is public child care. Interestingly, in Sweden, you get paid time off, but you have to take it. There is little public day care available (or at least this was the case a few years ago when I looked into it). So it forces people who want to work to take time off to care for their kids, whereas in many cases, they want to put the kids in day care and continue working.

    Caring for children is relatively thankless unskilled labor, so if you force educated parents to do it for long, they in the end will end up just not doing it. If you believe this is a problem, then you need to make sure that people have support, which means full-time daycare and other amenities.

    Frankly, countries need to make it easier for people to have children and raise them if they want to have a higher birth rate. It has worked at least somewhat in France and in Sweden, and more could be done.

    Warning women about decreased fertility is not going to work. People may say that they want two children, but people also say they want to lose ten pounds. People aren’t making decisions to have lots of children in Europe, and the reasons are structural. Frankly, as long as there is a social safety net in place for old age, you really don’t need to have kids around to take care of you, and all the annoyances of having children lead people not to have them. Only by making it easier for people to have careers and spending money and children at the same time will the birth rate go up.

  4. Also, if South Korea’s pro-natal policies are limited to cash payments, it won’t work very well. You can’t pay people enough to overcome the lifetime earnings lost due to having children.

  5. Limited

    I am riding on a limited express, one of the crack trains
    of the nation.
    Hurtling across the prairie into blue haze and dark air
    go fifteen all-steel coaches holding a thousand people.
    (All the coaches shall be scrap and rust and all the men
    and women laughing in the diners and sleepers shall
    pass to ashes.)
    I ask a man in the smoker where he is going and he
    answers: “Omaha.”

    Kindly visit the Economic Fractalist

  6. “Frankly, countries need to make it easier for people to have children and raise them if they want to have a higher birth rate. It has worked at least somewhat in France and in Sweden, and more could be done.”

    Well, we agree :).

    “Warning women about decreased fertility is not going to work.”

    Maybe not, but I presume you wouldn’t be against at least making the information available to them. At present, as Drago and Varner suggest, there is a lot of ignorance on this topic. I think it sould be taught as part of sex education in the schools, but then you need a lot of social policy instruments to back it up, otherwise you’re just going to skew gender relations again.

    “Frankly, as long as there is a social safety net in place for old age, you really don’t need to have kids around to take care of you”

    Yes, well obviously it’s the threat to this that may make people think about more children sooner. This may be the mid-term correction mechanism.

    “if South Korea’s pro-natal policies are limited to cash payments, it won’t work very well.”

    Oh, I agree. I only mentioned this not very interesting initiative because it was so symmetrical with the menarch? thing.

    “You can’t pay people enough to overcome the lifetime earnings lost…”

    Funnily enough I think we may have another asymmetry here. I’m not sure the decision to have children is an economic one, but the reasons for putting off having them often are, and this means at some level they can be addressed.

  7. “You can’t pay people enough to overcome the lifetime earnings lost…”

    “Funnily enough I think we may have another asymmetry here. I’m not sure the decision to have children is an economic one, but the reasons for putting off having them often are, and this means at some level they can be addressed.”

    It’s more than that. It is actually extremely financially punishing to have children for women. Numerous studies show that they are far more likely to lose their jobs and then have far more trouble getting new ones after the birth of a child. There is also the great loss of freedom inherent in having a child. (We just had a baby – believe me I know.) Also there is the great expense in raising the child, for example the expense of education, particularly higher education. Then there are health care costs for the child. Then there are the non-neglible health impacts from having a child, ranging from loss of bladder control to death. These are real issues that need to be dealt with if countries want to increase the birth rate.

    Everyone already knows about decreased fertility, and they don’t care. Ultimately, they have weighed the burdens and joys of children against the joys of employment and travel and income and found children wanting. Only if you can tip the scales back can you improve that.

    Here’s an example of a minimal threshold for pro-natal policies:

    (1) Free day care for everyone
    (2) Cash payments for children until the age of 18
    (3) Aggressive enforcement of anti-discrimination laws against women, particularly on the basis of motherhood for employment.
    (4) A nationwide network of licensed babysitters for times not covered by day care.
    (5) Government-mandated paternal and maternal leave policies that must be offered but are not obligatory.
    (6) Generous leave and vacation benefits for all workers – probably government mandated.

    The only country which really comes close is France, and they have a relatively healthy birth rate for Western Europe.

  8. “Hate to quibble but fertility rates in the US are not declining and have remained at around 2 for a while”

    On the quibbling thing, you are dropping slowly, in 2000 you were at 2.1, and obviously over the last 50 years you have been dropping substantially. My opinion is that massive immigration from the late 80s has put a break on the drop, or if you like a small plateau.

    The thing is Rupert there is not one fertility regime in the US but several. The end statistic is a composite. Lets let the prb explain:

    “(Population Bulletin excerpt, June 2000) The United States has higher fertility than any other country in the industrialized world. At the end of the 1990s, the total fertility rate (TFR) was about 1.4 children per woman in Europe, for example, while the U.S. rate was about 2.1. Yet surveys find that women in all these countries say they want about the same number of children, most often two. Why is fertility higher in the United States?

    One explanation for the higher U.S. fertility is that many European countries have racially homogeneous populations compared with the United States. In the United States, fertility rates differ among the nation’s varied racial and ethnic population groups. In 1998, the U.S. TFR of 2.1 children per woman was made up of several different rates: non-Hispanic white, 1.8; black, 2.2; American Indian, 2.1; Asian and Pacific Islander, 1.9; and Hispanic, 2.9.

    Now its the relative weighting of the Hispanic component which seems to be important, and it is the fertility of this group which seems to be declining through a steady rise in age at first child from a very low base. I think mid term the US has just as much reason to be worried as anyone else here.

  9. “declining fertility in the US”

    So to correct the quibble, what I should have said was the declining fertility of the hispanic US population (this is now declining steadily). Non-hispanic white is already more or less stable at European upper-end levels of below replacement 1.8 and may well not drop further.

    On the other side of the quibble, and in defence of the spirit if not the letter of what I was getting at, this wasn’t what the original paper was about, since it related to the long term historic decline which has occured in fertility in the US just like the rest of the OECD. Didn’t you find any of that even a little bit interesting (Rupert) and worthy of comment?

    Here’s a useful graph to illustrate the long term decline and recent plateau.:

  10. What is wrong with the intellectual elite of the world? Why must there be an ever increasing human population? To keep the Economy growing? Let the damned thing shrink! Simply pay people the same for less work…almost the current European model…if necessary, move to a more rational, though not revolutionary, redistribution of Wealth. Emphasize quality of life…not a head count quantity.

  11. Of course, to be viable in the long run, the human population must be at a steady state. But the path by which we approach that steady state makes all the difference; and Edward is concerned that fertility has decreased too fast for the existing social structures to cope.

    And even if you do feel that the marginal utility of an additional human being on this planet is negative, you should be concerned about a too-fast population decline, because in the aftermath of societal collapse, the environment tends to be the least of concerns.

    Here’s a talk that looks at a number of proposed reasons why some countries are prosperous, and others not:

    I won’t endorse everything it says, but the things it has to say about overpopulation are interesting. For example, if overpopulation is the key factor in third world poverty; that is to say, if there are too many people for the amount of resources, then we would expect prosperity in poor nations to rise after mass emigration.

    But even in the few cases where emigration has occurred on a scale sufficient to overcome natural growth (e.g., Ireland in the 1840s), we do not see this. We do see increased prosperity when poor nations drop their fertility from, say a TFR of 5 to 3; but this is a change in the age structure from children to workers; the population is still growing.

  12. just came to me there, ive no way of verifying this, but i seam to recall that it was french policy a number of years ago to show soft porn movies certain nights of the week to help the fertility of its citizens.

    im sure i heard this in relation to a bump in the number of babies born which was then traced back to these porn movies 9 months previously.

    so according to that logic we need more porn movies on TV.

  13. Hi traveller,

    Nice to see you found your way here as you transit the globe, I don’t expect to be able to give you all the answers you are looking for, but to save me repeating myself you might try this thread just a few posts down, I think people are discussing many of the points which interest you:

    btw, I take the point about the third world, but I don’t think many people seriously doubt that ‘population policy’ means very different things in Niger and Japan. What’s wrong with us all? I don’t know, but I suppose many of us aren’t convinced that the developed world going to the dogs is going to help the LDCs too much.

  14. Thanks for the welcome, Edward and all. I will study the links provided…because this something that truly and sincerely bothers me. I’m working hard for the next week or so…but as a personal quest, I need some internal quietude on this. I need to know where I stand and why. So I will look deeply into the links provided. Thanks.

    One argument is that the younger work force at some point can’t support the aging population. Okay, so what? Older people will have to tighten their belts, work longer, whatever. Suck it up and get over their sense of privilege. No biggie if they see the corresponding benefit that the world can at least survive this way.

    But I do want you to know that laying in bed last night I told myself to think around my prejudices…to get outside the box, or even to get a new box. Okay, in a hundred years the population of the U.S. is 900 million, maybe 500 million in 50 years…why do you care? Maybe the earth can sustain 12 or 24 billion people.

  15. @ traveller

    “I’m working hard for the next week or so.”

    Well don’t worry too much, there’s no urgency in that sense, this is going to take years, if not decades.

    “Older people will have to tighten their belts”

    Yep, but what if those belts are in Thailand and China, where birthrates are already well below replacement, or, of course, Russia. In these societies there is no meaningful welfare state, and the belts are pretty tight already.

    “Okay, in a hundred years the population of the U.S. is 900 million, maybe 500 million in 50 years…why do you care? Maybe the earth can sustain 12 or 24 billion people.”

    Don’t worry, there is a peak, not in carrying capacity – see Ester Boserup – but in our reproductive drive. Population should peak somewhere around the 9 billion mark in the fourth quarter of this century, and after that it will be coming down, not going up. The only real issue is how far down is down. It’s impossible to say at this stage. And also by then we’ll be into technologically engineered humans, so who knows.

    So the US at 900 million, this won’t happen, sleep calmly. I doubt it will reach 500. As I say, fertility in the US is long term on the way down, and the era of immigration will be past soon too. How many people from Ireland emmigrate to the US now? A trickle. Well the same will happen to Mexico, Ecuador etc etc. The Criaderos are about to go dry.

    Give Morrocco ten years and Europe won’t be able to count on re-inforcement from that source either. Despite the silly things the Trolls say, the main future source of immigration for Europe is Sub-Saharan Africa, this has hardly been tapped to date, but then a lot of the outcome here depends on how the AIDS tragedy evolves.

    So sleep peacefully tonight, but worry a bit more longer term I think :).

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