Growth retardation in utero: “small weights” under close surveillance

Everyone here calls them “the little weights”. Whether they are nestled in the wombs of future mothers or nestled in the incubators of the neonatal department of the Robert Debré hospital in Paris. Smaller than average, these babies suffer from stunted growth in utero. In the corridors of the maternity ward, Coumba, eight months pregnant, had never heard of it, like one in two women in France *. It was while passing her second ultrasound, only four months ago, that she heard these four letters “RCIU”: “The doctors simply explained to me that my baby was too small! “

* Opinionway survey for the PremUp Foundation

Growth retardation in utero: in 40% of cases, an unexplained origin

The RCIU is a complex notion: the fetus is underweight compared to its gestational age (hypotrophy), but the dynamics of its growth curve, regular or with a slowing down, even a break, is just as fundamental to make the diagnosis. ” In France, one in 10 babies is affected by this pathology. But we know less, it is also the first cause of death of babies! », Explains Professor Baud, head of the neonatal department at Robert Debré. This failure to grow is very often associated with a great prematurity, which is not without consequences on the future development of the child. To save the mother or baby, doctors are sometimes forced to induce labor well before the time. This is the case of Lætitia, who gave birth at 33 weeks of a baby girl weighing 1,2 kg. “The last two weeks she only took 20g and her heart was showing signs of weakness on monitoring. We had no other solution: she was better outside than inside. “In the neonatal service, the young mother shows the growth chart of her daughter who sits beside the incubator: the infant is gradually gaining weight. Lætitia learned around her 4th month of pregnancy that she suffered from a defect in the vascularization of her placenta. An essential organ from which the fetus draws everything it needs to grow. Placental insufficiency is therefore responsible for about 30% of cases of IUGR with for the expectant mother, sometimes formidable consequences: hypertension, pre-eclampsia … There are many causes of stunted growth. We suspect chronic diseases – diabetes, severe anemia -, products – tobacco, alcohol… and certain drugs. The mother’s advanced age or her thinness (BMI less than 18) could also interfere with the baby’s growth. In only 10% of cases, there is a fetal pathology, such as a chromosomal abnormality. But all of these possible causes call for mechanisms that are still poorly understood. And in 40% of IUGR cases, doctors have no explanation.

In utero growth retardation screening tools

Lying on an examination bed, Coumba obediently bends to the weekly recording of her baby’s heart. Then she will have an appointment with a midwife for the clinical exam, and she will be back in three days for another ultrasound. But Coumba is worried. This is his first baby and he doesn’t weigh too much. Barely 2 kg at eight months of pregnancy and above all, he took this last week only 20 g. The mother-to-be runs a hand over her plump little belly and grimaces, not big enough for her taste. To ensure that a baby grows well, practitioners also rely on this index, with the measurement of the uterine height. Performed from the 4th month of pregnancy, using a seamstress’s tape measure the distance between the fundus and the pubic symphysis. This data reported at the stage of pregnancy, ie 16 cm at 4 months for example, is then plotted on a reference curve, a bit like those which appear in the child’s health record. A measurement that allows over time to establish a curve to detect a possible slowdown in fetal growth. “It is a simple, non-invasive and inexpensive screening tool, while remaining reasonably precise”, assures Pr Jean-François Oury, head of the gyneco-obstetrics department. But this clinical examination has its limits. It only identifies half of the IUGRs. Ultrasound remains the technique of choice. At each session, the practitioner takes measurements of the fetus: the biparietal diameter (from one temple to the other) and the cephalic perimeter, which both reflect brain growth, the abdominal circumference which reflects its nutritional state and the length femur to assess its size. These measurements combined with learned algorithms give an estimate of the fetal weight, with a margin of error of about 10%. Reported on a reference curve, it makes it possible to locate more precisely an RCIU (diagram opposite). Once the diagnosis is made, the future mother is then subjected to a battery of examinations to find the cause.

Growth retardation in utero: too few treatments

But apart from hygiene advice, such as quitting smoking and eating well, more often than not there is not much you can do., apart from monitoring the rate of growth and normal blood flow in the umbilical cord to prevent complications and induce birth if necessary. As a precaution, the expectant mother is generally put to rest at home with visits to the maternity ward to assess the situation week by week. She is often hospitalized before childbirth to prepare her baby for her new life outside. In particular, by accelerating the maturation process of his lungs. “We do not have treatments to prevent IUGR in a patient who does not present a risk factor at the start”, laments Professor Oury. We can just, if there is a history of IUGR of placental origin, offer her an aspirin-based treatment for her next pregnancy. It’s quite effective. “Upstairs, in neonate, Professor Baud is also struggling to grow his“ little weights ”as best he can. Nestled in incubators, these babies are incubated by the whole team. They are fed solutions rich in nutrients and watched closely to avoid complications. “In the end, some will catch up, but others will remain disabled,” he regrets. To save these children and their parents a long Stations of the Cross, Prof. Baud is involved in the PremUp Foundation, which brings together a network of more than 200 doctors and researchers across Europe. Supported by the French Ministry of Research and Inserm, this Foundation created five years ago has given itself the mission of preventing the health of mothers and children. “This year we want to launch an extensive research program on IUGR. Our objective ? Develop biological markers to detect future mothers as early as possible, in order to limit the consequences of this growth retardation. Better understand the mechanisms of this pathology to develop treatments. To carry out this project and try to give birth to healthy children, the PremUp foundation needs to raise 450 €. “So let’s meet for the Baby Walk!” », Launches Professor Baud.

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