Anastasia Baker: Being pregnant is an exciting time in any woman's life, but also a time of anxiety, particularly with regard to whether her fetus is growing properly in the womb. Well, with me in the studio is Professor Philip Steer, Consultant Obstetrician at the Chelsea and Westminster Hospital in London. He is here to answer questions on fetal development. Welcome! So what are the main reasons why a baby might not be growing very well in the womb?
Professor Philip Steer: Well, there are a number of major reasons. One is that the baby might not be normal, might have congenital abnormalities. That's, of course, the reason we do so many scans, particularly around 18 to 22 weeks of pregnancy to check, so that if the baby is not growing very well, then we will do another scan partly to measure the size of the baby, but also to check that there isn't an abnormality in the baby that we've missed.
Another important cause of the baby being small is the mother who's seriously under weight or has some medical disease which prevents her pumping blood through the placenta adequately. So it's important that women get themselves into good shape and as fit and healthy as possible before they actually embark on a pregnancy.
Another important cause is a condition we call preeclampsia. This is pregnancy-induced high blood pressure. This occurs in about 2% to 3 % of first pregnancies in a severe form and in about 10% in a mild form. If women develop this condition, they are more likely to have a baby that's not growing properly. So, we will screen them for that.
Anastasia Baker: If you've presumably got a history of this sort of thing in your family, that would be something else you take into consideration when you're initially doing and screening moms.
Professor Philip Steer: Sure! Yes! The most valuable indicator of a woman who's likely to have a small baby is actually that she's had a small baby before or a baby that hasn't grown properly before.
Anastasia Baker: And in those cases, then what would you do? Scan her more?
Professor Philip Steer: Yes, normally we would scan the baby regularly about once every four weeks. As long as the baby is growing normally, up the growth charts, and keeping pace with the growth as it should be, not because necessarily it's very small or very large, it can be small and healthy, but then it will grow normally just along the small line as it were or the large line.
Anastasia Baker: I suppose, it's one that stops growing.
Professor Philip Steer: It's when it stops growing is when we're concerned. So that will be done about every four weeks. If the growth starts to tail off and it's not as good as it should be, then we start looking at the blood flow in the placenta. We actually look at the blood vessels in the umbilical cord leading to the placenta and we look at the ratio of how fast the blood is flowing when the baby's heartbeats compared to when it's not. Looking at that ratio, we can actually work out whether the placenta is allowing the blood to go through easily enough or not.
We can do that every week. If that then becomes abnormal, we will then start monitoring the baby's heartbeats sometimes 2 or 3 times a day on what we call fetal heart monitor for up to 40 minutes at a time. Then if that becomes abnormal, that means the baby is not getting enough oxygen and we should deliver it. So, there's sort of staged progress of this type of investigation.
Anastasia Baker: Those ultrasounds scans you were talking about, can they be a health risk to a baby in a womb?
Professor Philip Steer: There is no known risk currently to ultrasound. There have been a number of studies over the years which have suggested that they might reduce the incidents of right-handedness. They don't make baby left-handed, but the babies are slightly less likely to be right-handed. So they become a bit more ambidextrous. There is no known harmful effect in relation to that.
Apart from that, nothing else has shown up, but nonetheless, there are harmful effects from having unnecessary scans related to picking up things which look abnormal, but which turn out not to be. We call this a false positive. It's for this reason that we don't recommend that people have scans when there isn't a medical reason for it.
Anastasia Baker: Right, I see.
Professor Philip Steer: In fact, the FDA, the Federal Drug Administration and the American College of Obstetricians and Gynecologists have recommended that women shouldn't have scans unless there's a medical reason that they're recommended to have one by their obstetrician.
Anastasia Baker: But do you say, I mean, I remember frantically getting on the scales every week, every month checking that I was growing and getting out my measuring tape. Is that hopeless then to do all of that?
Professor Philip Steer: It's not hopeless. The mother's weight is actually rather important for two reasons. If the mother is seriously underweight when she gets pregnant, then her baby is likely to be much smaller and it's more likely to be born premature as well. So in women who are very thin, when they first appear for antenatal care, we would want to monitor their weight and encourage them to put on plenty of weight.
Equally, if a mother is overweight, seriously overweight, she will have a baby that -- she is more likely to have a baby that's very big. This, of course, then gives rise to difficult births. Moreover, because she is large herself, it can make it quite difficult to detect if her baby isn't growing properly. So the ideal thing is to be in the average weight range, which is a body mass index of around 20 to 25. Now for a woman that is in that average range to start with, the average weight gain in pregnancy is about 12 kilograms. Okay, so that's about 25 to 30 pounds.
Anastasia Baker: Right!
Professor Philip Steer: However, it doesn't make a big difference to the baby's weight, whether she puts on a lot of weight or a little, provided she's normal to start with. If she's underweight, then it's important that she puts on weight. If she's very overweight, it's actually important for the mother's help and to help prevent the baby getting too big, that she doesn't put on too much weight. So monitoring will be restricting your diet or altering your diet to keep your weight steady, if you've got a body mass index over 30 is also an important priority. But if your body mass index is normal, 20 to 25, then essentially, there's not a lot you can do by eating or not eating to change the way your baby grows.
Anastasia Baker: For a baby that hasn't grown very well in the womb during pregnancy and is born, what are the problems that, that can present later in life?
Professor Philip Steer: Well, later in life, it can lead to problems such as high blood pressure and diabetes. The reason for this is, when the baby is born, at the due date, it normally has quite a lot of its own fat, lot of subcutaneous fat, and it uses that to keep its own blood sugar up and to live off until it has established breastfeeding, effectively.
Now, if the baby doesn't have enough fat, then the first thing that can happen is that the blood sugar drops very dramatically in the baby. If the brain is then starved of enough sugar, then this can actually cause brain damage. So very low blood sugars or hyperglycemia, which is the technical term, is actually a significant cause of brain damage which then, of course, leads on to problems and serious problems in later life.
Now the other thing that happens is that the baby's blood pressure and the amount it eats, is to some extent regulated by how well it's been nourished during the womb. If a baby hasn't been nourished very well and then is fed, particularly if it is bottlefed, and it gains a lot of weight, if it gains weight very rapidly in the first year or two after birth, then this overwhelms the control mechanisms for its blood sugar and also for its blood pressure. So we know that these people, when they are 30, 40, 50, are more likely to have both high blood pressure and diabetes themselves. So this is why the effective diet and proper nutrition can actually lead on from one generation to another.
Anastasia Baker: But barring congenital disease and barring preeclampsia, if you have a good diet and you exercise regularly, can you avoid these sorts of problems occurring?
Professor Philip Steer: You can to a large extent. However, some babies are just genetically programmed to be small. They're growing up the low centiles, and as long as they grow at a correct rate and they come out and they're vigorous and healthy, there's nothing intrinsically wrong about being small. I mean, I'm small and I sometimes hate the mums, well, think about Napoleon, he was just 5 feet tall, but he was pretty effective.
Anastasia Baker: My babies were small. What I was told to do in the last week was to stuff myself. You were saying that's not what they need to do?
Professor Philip Steer: No, absolutely not. So just being small is not a big stuff for worry. What we have to look at or bear in mind is that small babies maybe malnourished. So after they are born, the pediatricians will come and they will assess the baby, look at the amount of fat, look at how well it keeps its blood sugar up, look at the way it's behaving, and then they will either say, yeah, your baby is just a normal small healthy baby, no need to worry, or your baby actually should have been much bigger. It's actually malnourished and it's therefore having problems with the blood sugar or these other difficulties and therefore we need to feed the baby up in the neonatal unit. That is quite a common thing to have to happen. So by and large, probably, 3 out of 4 small babies are okay, but 1 out of 4 won't be, and they are the ones that we need to pick up on.
Anastasia Baker: Sorry for the cliché, but is this a growing problem or do you feel you're countering the problem quite well?
Professor Philip Steer: No, the growing problem actually within maternity is actually maternal obesity.
Anastasia Baker: Really?
Professor Philip Steer: The very high proportion of very overweight women, who become diabetic, themselves, and who're causing their children to be diabetic.
Anastasia Baker: So what's being done about that?
Professor Philip Steer: Well, I think that's a public health issue. I think we need more publicity to explain to women particularly when they're thinking about having babies.
Anastasia Baker: It's not okay to eat whatever you want during pregnancy.
Professor Philip Steer: Absolutely! It's much better to have your five fruits and vegetables and cut down on the chips and potatoes. That will give you a healthy baby. Particularly, not only if you're overweight will you have potentially a very large baby, but if your baby is unlucky and doesn't grow properly, even though you're overweight, it's quite likely to be missed, because it's very difficult for the obstetrician or the midwife to actually detect that the baby is small in the womb because there's so much for the mum to feel through. Short of doing scans on everyone, which we don't think is a good idea for reasons I explained earlier, there's no other way of detecting it.
Anastasia Baker: So other than scans, there's no other way, not the measuring and not the sort of --
Professor Philip Steer: Measuring, what we call the frontal height which is from the pubic bone to the top of the womb is a reasonable screening test. In an average-weight woman, when it's being done by someone carefully, we will pick up about half of all babies that aren't going properly, and probably two-thirds of the babies that are really growing poorly, but, of course, that assumes that we can feel the baby easily. If the mother is really grossly obese, then it becomes impossible to do that.
Anastasia Baker: What about taking vitamins and folic acids? Can that help?
Professor Philip Steer: Folic acid is a very important vitamin and all women thinking about being pregnant should take about 300 micrograms a day of folic acid for at least 3 months before they conceive. That's the ideal and then they should continue it for at least 3 months after they have conceived; so up until about 12 to 14 weeks of pregnancy. After that, it doesn't appear to be so vital, but it's particularly important not just in fetal growth in the early stages but also in preventing spina bifida.
Anastasia Baker: Where do you get folic acid from?
Professor Philip Steer: Well, you can actually get it from the right sort of food, and so green vegetables and broccoli and all these sorts of things have lots and lots of folic acid in them. But it's generally recommended that you get the normal supplementary folic acid that you can buy at any normal chemist that sells prenatal supplements.
Anastasia Baker: So, this isn't something that the midwife would naturally give you. They would recommend that you go and get it.
Professor Philip Steer: Well, unfortunately, the midwives haven't worked out yet how to decide when women are going to become pregnant.
Anastasia Baker: Alright! Sorry! I thought --
Professor Philip Steer: So, the women actually have to take responsibility for this, themselves. But that is the only one that is definitely scientifically proved. Other multivitamins maybe beneficial, they may not. There's no really good scientific evidence for that. We know that too much certain things, vitamin E, liver, for example, is bad for pregnancy. So the strong recommendation really is, it is always better, apart from the folic acid issue, to take your vitamins as a good balanced diet. That's safer and it's going to give you the right balance between the different vitamins, not too much of this, not too little that.
Anastasia Baker: What I was told in my pregnancy was, regular rest and relaxation and get the legs up and blood flowing into the placenta, all of that you would advise people to do, which is not easy if you're a working mother.
Professor Philip Steer: Well, two points there. The first point is that a lot of progesterone is made in the placenta. This is the pregnancy hormone. If you get enough progesterone, it's actually an anesthetic. It makes people feel very tired. So this is a natural thing that happens in pregnancy and, its nature, encouraging women to do less, to take more rest and relaxation.
Anastasia Baker: But they don't or they can't in many cases.
Professor Philip Steer: Well, if you say they can't, then I think women need to think about their priorities, do you want a healthy baby or do you want a high-powered job? But, if there is a conflict, then as an obstetrician, speaking on behalf of the baby, I would say, go for the baby.
Anastasia Baker: Is there evidence to suggest that working women do have smaller babies?
Professor Philip Steer: No. A normal occupation, normal work is actually good. There's evidence that women who have a normal job actually have better outcomes for their pregnancies than women, for example, unemployed. The sort of jobs that are bound for you are jobs with a lot of heavy physical work where you run your feet for more than 4 hours a day or where there's a lot of emotional, physiological stress. We know from quite good research that those things are bad for pregnancies.
So if you have the sort of job that you're comfortable with, you don't get over tired, you've got a reasonable boss, you can get your feet up as soon as you get home to compensate, then that's good. There's absolutely nothing wrong with that. But I have seen women who've got very demanding jobs or very physically difficult jobs and they sometimes have to make --
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