Crispi divides her day between routine visits to pregnant women, the supervision of high-risk pregnancies and researching fetal development in the historic Maternitat de Barcelona, in the heart of Catalonia’s capital. Her latest findings, published in the scientific journal Jama, found that a balanced diet and a stress-reducing relaxation program for mothers can reduce the risk of babies being born underweight.
Low weight in babies “can cause more problems in childbirth that require an incubator… in the long term, [there] is a higher risk of cardiovascular, metabolic, learning or respiratory problems,” says Crispi, a specialist in fetal cardiology. She has just received the Jesús Serra 2022 Research Award – worth €35,000 – to continue her research in this field.
Question. What are the risk factors that can lead to low birth weight?
Answer. The main cause is that the placenta does not work well and does not feed the baby properly. Why it doesn’t work well, we don’t know. It’s probably multifactorial. The placenta has cells from the baby and has to attach itself to the mother’s uterus, implant itself and be able to use the mother’s blood and food. The mother has to have an immunological tolerance to allow for this. Ideally, there has to be an understanding between the mother and the placenta… but older mothers, or mothers with immunological diseases or coagulation disorders, have bodies that do not allow for the placenta to implant itself. This causes problems. Then, there are other factors, such as tobacco and alcohol use, which can also negatively impact this process. And then there are other external elements, such as nutrition… if it’s not optimal, the food that will reach the baby is of a poorer quality, which means that the placenta also doesn’t grow. In addition, with stress, cortisol increases; this alters some receptors in the placenta.
Q. In your study, you looked at the influence of diet. Why did you choose to focus on this?
A. We have been studying the negative effects of being born with low weight for more than 15 years. We tried to utilize drugs to improve growth, but it was a disaster. So, we said: we have to do something before the problem occurs, because once the placenta malfunctions, there is little that can be done.
We studied more than a thousand pregnant women to find out what factors were influencing them. We knew that, in underdeveloped countries, diet was an important factor… although here, in Spain, we thought that mothers ate well. But we found that the mothers of toddlers were eating worse than the moms of non-toddlers. We also learned that less than 10% of pregnant women ate well. This means that 90% of pregnant women do not eat optimally. In other words, it’s not that they eat very poorly, but eating optimally implies taking in all the nutrients you need in an exact proportion, without missing anything essential.
Q. And what does an optimal diet look like?
A. Well, the mother should have a good base of fruit, vegetables and cereals – ideally whole grains – and optimal amounts of protein. We looked, for example, at the mothers of small babies who ate too little protein because, sometimes, during pregnancy, they found a distaste for meat or fish. We also found that there was a nutritional deficiency of calcium, because you have to eat a lot more dairy products while carrying a baby. Perhaps, if they were not pregnant, the women wouldn’t have these deficiencies, but with pregnancy, nutritional requirements increase.
Q. Why don’t the mothers eat well?
A. We believe that there is a percentage that simply don’t worry about how much or what they are eating. Or, because of nausea, or because they work and don’t have the time to find a balance. But there is also a very important percentage of pregnant mothers who make an effort and believe that they are eating well… the problem is that nobody explains to them how to do it correctly. We gynecologists generally don’t have training in this. We mostly dedicate ourselves to prohibiting things: fish due to mercury, ham due to toxoplasmosis, unpasteurized dairy products due to listeria, etc. We don’t explain much – if the pregnant woman asks a gynecologist about nutrition, they usually don’t know how to answer.
Q. In you study, you showed that dietary changes could reduce the number of underweight babies. What else can a better diet do?
A. We have seen that it also reduces pre-eclampsia, which is hypertension in pregnancy. But we did not see dietary changes reducing the number of premature babies.
Q. One of the limitations of the study is that it was done in a high-income setting. To what extent is it feasible and realistic to ask all mothers to eat a healthy diet? Eating well is often much more expensive than eating poorly.
A. 70% of the women who participated in the study were of a high economic level, this is true. But when working with the data, we saw that there was also a positive effect on those of lower socioeconomic levels. Healthy food is expensive, yes, but you can also adapt a diet based on income. These women also appreciated that someone explained to them that, within their income range, they could also make better choices at the grocery store.
Q. The other part of the study was stress reduction via a relaxation program.
A. Stress has an effect on our entire society. It is assumed that the pregnant woman is a happy woman… but the stress of pregnancy is closely related to the fear of the unknown. You do not know if it is going to go well or badly. This generates worry, which subsequently increases your cortisol levels. Pregnancy, whether you are of a high or low socioeconomic level, generates some intrinsic fears that are very powerful: you do not know if the baby is going to be healthy or unhealthy. There are internal questions about whether you will be a good mother or not, of how strong the relationship with your partner is, if you will be able to continue in your professional career… there are many uncertainties. And uncertainty is the basis of stress.
Q. What role does cortisol play in fetal health?
A. Cortisol is the hormone that we create to put us on alert when we are in a stressful situation. Like in a fire, for example. Having high cortisol at a specific time is good. What is not good is having it high all the time, or for a long time. During pregnancy, cortisol is necessary for the development of the baby, but very high levels are bad. If you receive too many doses of cortisol, babies are born smaller.
Q. How is your research going now?
A. We are trying to understand the multiple ways in which a diet can reduce prenatal problems from developing. One hypothesis is that what the mother eats during pregnancy are like the pieces with which the baby is made: the baby is made by taking in proteins, lipids, carbohydrates. But we believe that there can also be a direct effect on the placenta: eating better can make the placenta of better quality, which makes it feed the baby more efficiently. We are studying the placenta and, within it, the polyphenols – components derived from olive oil – and nutrient carriers to understand which components of a diet can bolster the placenta.
Q. With these results, can there be a risk in putting excess responsibility on the mother?
A. On the contrary, the mother is already making an effort. The only thing that the study intends is to give tools to empower pregnant women. The purpose is not to place blame – everyone does the best they can.
Q. Some time ago, there was a big controversy surrounding an influencer (also a doctor) who said that there was nothing wrong with having a glass of alcohol while pregnant.
A. No. Zero tolerance to alcohol. Alcohol goes straight to the baby, to the placenta. And tobacco should also be zero.
Q. Do the mother’s habits completely modulate the baby’s health?
A. Yes, totally. A third of adult health depends on our genetics; another third, on our habits of life after birth; and another third of our habits in the prenatal stage… which are entirely those of the mother. In other words, a third of our health depends on how the mother took care of herself.
Q. At the awards ceremony, you highlighted the importance of prenatal research and said that it was “neglected.” Why did you say this?
A. Firstly because, until 50 years ago, the field didn’t exist. Fetal medicine was born with ultrasound – it is a relatively new specialty and much remains to be discovered.
The second reason is that, when it comes to research grants, pregnancy is not given much importance. I don’t know if it’s because we’re women, or because the ones who give out the money are men who worry a lot about prostate cancer or Alzheimer’s, but maybe not about pregnancy. We always have to find ways to stretch money, because there are rarely awards for pregnancy research.
Q. What is left to learn about fetal medicine?
A. We are putting a lot of focus on the placenta, because it is an extremely complicated organ to study. It’s very heterogeneous, it changes a lot during pregnancy and has rarely been examined. It was something that came out after childbirth and was immediately thrown in the trash, because it’s kind of ugly, disgusting. But inside the uterus, it is cuter! It’s a wonderful organ, the basis of low birth weight, of pre-eclampsia, of many diseases. I work in the cardiovascular area and we also have to understand more about how the heart works… why it sometimes doesn’t develop well. The more you study, the more questions you have.