“When are you due?”

It’s pretty much the first question from everyone who finds out that you’re pregnant. I think on a rational level, the vast majority of people know that you can’t really predict when babies will be born, but I suspect the majority still believe that the Estimated Due Date (EDD) is scientific and accurate at least some of the time. The truth is though, it’s an arbitrary date determined by outdated pseudo science, a best guess, based on the probable misunderstandings of ancient theories.

The theory goes that pregnancy lasts for 40 weeks (9 months + 1 week) from the first day of a woman’s last menstrual period (LMP). Where did this idea come from? It’s called Naagele’s Rule, named after German obstetrician Franz Karl Naegele (1778–1851), who devised the formula. I don’t believe that Naegele plucked this idea out of thin air, it is likely that he read Aristotle’s theory that pregnancy lasts for about 10 lunar months, and Naegele assumed that a lunar month was 28 days.

Aristotle, however, was what I call a “well rounded wise man”. He was a philosopher, mathematician, scientist and sociologist. With his education in physics, it is extremely likely that he knew that a lunar month is not in fact 28 days, but nearly 29.5 days, making 10 lunar months 295 days, NOT 280, over 42 weeks, NOT 40. What a difference to pregnancy length that makes. What Aristotle actually wrote was:

pregnancy may be of 7 months’ duration or of 8 months or of 9 and still
more commonly of 10 (lunar) months, whilst some women go even into the
eleventh month. 


Naegele’s Rule also assumes that all women have exactly 28 day cycles and that they ovulate on cycle day 14. Obviously, this is not true. There is great variation in both cycle length and ovulation timing. There is a suggested alternative formula, Parikh’s Formula, which is a date calculated by adding 9 months to a woman’s LMP, then adding the length of her average cycle, then subtracting 21 days. For example, a woman with 35 day cycles whose last period began on 1st January would do the following calculation:

1st January + 9 months = 1st October

1st October + 35 days = 4th November

4th November – 21 days = 14th October

This EDD is approximately one week later than EDD calculated by Naegele’s Rule.

A small study in 1990 by Mittendorf et al. found that the parity of the woman was a factor in the length of her pregnancy. First time mums had an average pregnancy of 41 weeks and 1 day (41+1), second and subsequent babies arrived at an average of 40+3. Some studies have also found racial variations in pregnancy length.

Normal human gestation is usually defined as 37-42 weeks, by the WHO, maternity professionals and academics, and yet the myth of the EDD persists. Midwives and obstetricians do nothing to correct this misconception, they often seem to fixate on the EDD, first calculated by LMP and then by ultrasound, the infamous “dating scan” that most pregnant women have at about 12 weeks in the UK. (My views on the reliability of ultrasound are explored in my previous post “Guess the Weight”). The dating scan has a 6 day margin for error, officially, and yet it is relied upon so strongly that a woman’s knowledge about her own body is usually dismissed in favour of what the machine says. For instance, were we using NHS maternity services for this pregnancy, the sonographer that did our early pregnancy scan (for reassurance) would have us believe that this baby was conceived 8 days prior to ovulation and 3 weeks after the last time we made an attempt to conceive, a passing familiarity with human conception will tell you that this is impossible. No, in fact, this baby was conceived when I actually ovulated and not by some freaky and convoluted miracle process of my dear husband’s swimmers breaking all records and my body releasing an egg more than a week before all the physical signs indicated the possibility.

Even so, knowing when you conceived doesn’t actually give you any particular insight into how long your pregnancy will turn out to be. Gestation is a natural process and as such, it can’t be timetabled. There is great variation and most of it is completely incomprehensible, there is no known explanation for the wide variety in gestation lengths, it’s just an organic part of life and one that I think we would all do well to accept.
People pin all of this importance on the EDD and their care providers make it worse by rushing to intervene as soon as pregnancy continues beyond 40 weeks, which it does in more than 50% of all pregnancies! In my own small way, I try to challenge this by reminding people of the “Estimated” in EDD and emphasising that normal pregnancy is 37-42 weeks. I have also refused to tell anyone the precise date that I will be 40 weeks pregnant. I know when that date is, as I know when we conceived, but it is not my EDD, to me there simply is no such thing as an EDD. Our midwife knows the 40 week date, but together we have no expectation that there is anything special about that one day. It’s a vaguely useful day to note down so that we have an idea of what 5-6 week period the baby might put in an appearance, that’s all. To all of our friends, family, neighbours and random acquaintances, we expect this baby to arrive some time in February, probably.

When Headlines Are WRONG

I think most people probably know that newspapers are not always the most reliable sources when it comes to conveying factual information. Certain papers tend to sensationalise things and some even tell outright lies to their readers in order to sell more papers. Because the real news is often nowhere near as interesting as the made-up stuff.

What kinds of headlines sell newspapers? Babies dying, sadly, is a big seller and it’s one we’ve seen in the wake of the release of the long-awaited Birthplace Report, which was published yesterday. The Daily Fail notoriously misreported the study’s findings, with a lead headline of

First-time mothers who opt for home birth face triple the risk of death or brain damage in child

  • Half of women who chose home births had to be transferred to hospitals due to complications

Both of these statements are complete lies. Not just minor misrepresentations or misinterpretations of the facts, but actual lies, told to scare the public and stir up an emotive debate.

You may be able to tell that I have absolutely no respect for this publication, or others like it.

So, what is the truth behind this sensational headline?

The Birthplace report really did find an increased risk of death (stillbirth and neonatal mortality), brain damage (infant encephalopathy), meconium aspiration syndrome and bone fractures in the arm and collar bone in babies of first time mothers who plan home births, deaths did NOT make up the majority of these outcomes. HOWEVER, it was less than twice the risk of babies born in other settings, not three times the risk. Also, the actual risk is still less than 1% and the results are looking at the short term only, it is entirely likely that most of these babies are perfectly well after treatment.

Mothers who have children already face absolutely no increased risk to their babies by birthing at home.

There were so few infant mortalities in the study that the researchers decided to compound the results of a range of adverse outcomes in order to produce a study with statistically significant results. I have mixed views on this. On the one hand, it muddies the waters by mixing up the worst case scenario for the baby with a host of lesser problems. On the other, it does demonstrate very clearly just how safe birth is in the UK today (with a less than 1% risk of anything significantly bad happening to a baby, regardless of where it is born or how many babies the mother has had before).

As for the “Fail”‘s other assertion, well actually, it was less than half of mums, about 40%, who transferred and most of them were not for “complications” but for the infamous “failure to progress” and epidural pain relief.

A more accurate, and just as attention-grabbing headline might have read

Low risk mothers who plan hospital births are three times more likely to have an unplanned caesarean section than in any other birth setting

The study found that women planning births at home and in birth centres (both freestanding and attached to an obstetric unit) were overwhelmingly better off than those planning to birth in obstetric units. Women in hospital had a mere 58% chance of having a normal birth, whereas those planning to remain at home had an 88% chance. This study didn’t even touch on long-term results, such as breastfeeding duration or mental health.

These are all low risk women. And their health matters. Yes, we all care very much about babies and no one loves a mother’s baby or wants the best for it as much as she does… but mothers matter too. A healthy baby might not stay that way with a damaged mother and a damaged mother may remain damaged for the rest of her life as a result of her birth experience.

The elephant in the room with these results is… why do women do worse in hospital than in any other setting? The study can’t tell us that, but there are a number of theories. The most compelling to me personally, is that obstetricians view birth as a problem that needs fixing and that they have a tendency to step in and interfere where no interference is actually necessary. In an obstetric-led unit, even though all low risk women will be cared for primarily by midwives, there are always obstetricians waiting in the wings for something to do. At the study launch event at the Royal Society of Medicine yesterday, Dr David Richmond, Vice President of the Royal College of Obstetricians & Gynaecologists (RCOG)  implied as much in his talk when he showed a slide of Mount Everest and quoted Sir Edmund Hillary, who famously replied to the question of why he climbed Everest with “Because it’s there”.

Those of us who have taken an interest in normal birth and taken the time to investigate how birth works, are aware that birth goes the smoothest away from time limits, bright lights, loud noises, routine interventions and alien environments, i.e. at home. So the results of this study are no surprise. Women do best at home.

I think it’s very important for women to have access to the right information, presented in the right way, to enable them to make choices for their births, so let’s just compare the statistics for a moment.

  • A first time mum has roughly 0.5% chance of anything bad happening to her baby in hospital or in a midwife led unit. She has a less than 1% chance of anything bad happening to her baby at home. At home her baby is nearly two times more likely to have an adverse outcome.
  • The same mum has a roughly 15% chance of an instrumental delivery (ventouse or forceps) in hospital and 4% chance at home. In hospital it is over three times more likely.
  • She has a 10% chance of a c-section in hospital, less than 3% chance at home. In hospital it is over three times more likely.
  • There is a 23.5% chance of having her labour augmented in hospital (with all of the associated risks to both her and the baby that come with that) and just 5.4% chance at home. In hospital it is over four times more likely.

I’ll leave it up to each reader to digest those figures and decide for themselves where their preference for birth place lies, but do remember that these are all like-for-like mums, they are all low risk, so what these numbers suggest is that it IS the place of birth that influences the numbers. The mere fact of being in hospital makes these interventions more likely, and avoidable by staying at home or birthing in a birth centre (which tend to come out roughly the same as home or somewhere in between the two). It’s not that more women in hospital need these interventions because they are high risk.

Next time you read a sensational headline in the press, take a moment to think about what they aren’t telling you or the fact that they could actually be telling a barefaced lie.

Switching Off and Being a “Normal Mum”

Twice in just a few days I have been in situations where it is probably best to switch off my campaign head and shut up, be a “normal mum”, whatever that might mean. The first of these was the first of two Natal Hypnotherapy workshops that hubby and I are attending in preparation for this birth and I didn’t do so well. The second was my aquanatal class today. I did better.

I’ve always found it hard to know when to shut up and keep my opinions to myself and have probably pushed a fair few people away because of it in the course of my life. When my passions are raised they tend to spill out of me, but I’ve worked hard to get it under control and generally I think I do a better job now than ever before.

When it comes to birth, it’s a bigger challenge than most issues I’ve felt passionate about in my life. It’s such an intimate topic, birth is the single most significant physical act that a woman embarks upon and also the one fraught with the highest emotional investment too. I know that birth can be amazing and I know that all women deserve excellent maternity care. I know that there are fundamental, systemic problems with NHS maternity services that prevent the majority of women from having the births they should have. I hate seeing women being trampled on and abused by their care providers and it makes me angry and deeply saddened that I can even use the word “abused” there and know it to be no overstatement or falsehood.

Last Friday at the Natal Hypnotherapy workshop, I had to tell myself not to go to it expecting that I would know everything already and to accept any new knowledge or tools presented to me. At one point, having answered every question about hormones and birthing positions that we were asked, I actually apologised and made an effort to keep my mouth shut to give one of the others a chance to answer something. I felt a bit like Hermione Granger.

One of the other ladies on the course is also planning a VBAC and I couldn’t stop myself from making suggestions about which interventions she might wish to think more about. I don’t think I came on too strong there, but over lunch discussion turned to placentas (yes, over lunch) and I went and mentioned the fact that we’re planning a lotus birth. I think the others were mostly just intrigued, until I went a step too far and mentioned consuming the placenta as another option. I suspect I came away from lunch looking like a very weird hippy.

This afternoon was my aquanatal class, which I go to for the exercise and “me” time. After the class we sit in the café for a chat and the first time I went it was just me and the two midwives who run the class. We had a fantastic chat and I told them about what I do and which groups I’m involved in. They are lovely ladies, very keen on what they do, which is helping women keep fit and healthy in pregnancy and they have their gripes with the NHS, and so no longer work within it. However, I do suspect that they don’t see quite the same problems that I do.

Today there were others present, one lady due in a month or so and another who had a home birth a few months ago, another lady due early next year. I was very grateful for the home birthing mum’s presence, as she was able to say some of the things I would have loved to say, but in a much more palatable way than I can sometimes be guilty of. She was a normal, non-campaigning mum, a mum who only breastfed her eldest for a few months (compared to my 2.5 years) and who told us that her home birth “bloody hurt” and that she had a third degree tear and had to have a spinal afterwards while being stitched up. She was absolutely supportive of home birth and said she would do it again if she ever has another baby, but she definitely wasn’t ever going to come across as the dreaded hippy-type or militant birth campaigner. Like me.

For the most part I just nodded in agreement with her. When the nearly-due lady asked if it was possible to hire a midwife privately, as hers is so rubbish, I was able to espouse the virtues of independent midwifery and I also mentioned doulas. I think I managed to toe the line I find so difficult, that of switching off my campaigning head and just being a normal mum, talking to another normal mum and hopefully pointing her gently in a sensible direction that will help make a positive birth attainable. Maybe next week she’ll be telling us that she’s booked a home birth and hired a doula. Maybe even an IM. I hope so, for her sake.

Basic Biology

This article originally appeared on the site http://www.fourmums.com and has since been reproduced in the AIMS journal. I thought I’d get my new blog off to a flying start and include a copy here. Enjoy.

I’m not a science person. I was never that interested in it at school, I don’t think like a scientist, or at least, I don’t think I do. I was always much more interested in the arts and I still am. But I like science, I think science is important and I’ve picked up a few scientific facts throughout my life that have enhanced my understanding of the world.

Birth both is and isn’t a topic for science. It is a normal biological function and can in some ways be studied, categorised and understood in basic scientific terms. But it is also unpredictable and a deeply emotional time for women and their families and so we cannot view it in a cold, sterile, scientific vacuum.

Here are a couple of very basic scientific facts that I think are important in understanding a little bit about human procreation. Continue reading