Birth weight is mainly related to maternal BMI before pregnancy

Birth weight is primarily related to body mass index (BMI, weight ratio of the square of the height) of the mother before pregnancy, show the first results of the French EDEN study, presented at ' a press conference in Paris.
Factors influence the baby's weight
The Study on the Determinants of pre-and postnatal development of child health (EDEN) was launched in 2003 by four Inserm laboratories and maternity CHU de Poitiers and Nancy. She recruited 2002 women at the end of the first trimester of pregnancy until the end of 2006, and whose children will be followed up their five years.

It aims to take into account a multitude of factors such as birth weight, the health of the mother, nutrition, and psycho-social environment in which it operates, its exposure to toxic and allergenic, current incidents pregnancy, breastfeeding and to consider what role each of these factors plays in the further development of the child.

While some risk factors such as tobacco, alcohol, cannabis, heavy metals or as protection of breastfeeding are well documented, remain unknown, say the authors of the study in the press.

Its duration and the number of women included, as well as the number of parameters to be analyzed, this is the largest study on the subject in France, they add.

A total of 1907 deliveries took place, 1,551 samples of cord blood and placenta fragments were made, 1669 Postal follow-up questionnaires assessing children's health to four months were recovered and 1,774 parents completed a questionnaire about them.

The first results concern the relationship between maternal BMI and the events during pregnancy and the neonatal period, complemented by the study of placental development and maternal metabolism.

They show that the baby's weight varies little the mother take 2 or 12 kg during pregnancy, but it is bigger when more (over 12 kg excluding fetal weight and annexes, about 15 kg total) that the impact of those pounds appears on the baby's weight. They show that birth weight is primarily related to maternal BMI before pregnancy.

Arguably a genetic explanation for this observation, but it appears that the impact of the build of the mother is more important than the father, which favors the hypothesis of a specific effect of the mother.

In addition, placental weight is also correlated with baseline BMI of the mother. One of the next steps in the EDEN study will be to better understand how maternal influences the development and functioning of the placenta nutritional status.

Use of reserves
Furthermore, the study shows that during pregnancy, especially in the third trimester, women mobilize the reserves stored in their fat tissue to support the growing fetus. In fact, obese women gain less weight during pregnancy (4.5 kg average non-baby weight) than lean women (10 kg on average), in part because they use their reserves for their baby.

Even taking into account the presence of gestational diabetes, more frequent in obese or overweight women and promoting weight gain fetal excessively, obese women are three times more often than a big baby of normal weight.

"It is therefore in the category of women of normal BMI (18.5 to 25 kg / m²) in before the start of the baby was most likely to give birth to month an infant proper weight, "says a statement of EDEN.

This result "should encourage women and the medical profession to be concerned about the future health of baby upstream of the design."

Difficulties initiation of breastfeeding among obese mothers
The study also shows that when the mother breastfeeds, the premature loss of weight of the newborn in the first three days of life is higher among those whose mother is overweight or obese than others, which may reflect a difficulty in initiation of breastfeeding among women, who need special support.

The study of the nutrition of mothers included in EDEN attempt to provide more accurate information about the role of nutrition in young women in the course of pregnancy and child development, health, eating behavior and growth.

The study also confirmed a link between maternal overweight and risk of gestational diabetes and high blood pressure during pregnancy, and the percentage of hospitalizations during pregnancy and cesarean rate appear to be related to maternal body size.

The transfer rate of the newborn or neonatal resuscitation is also higher among obese women, but this is partly due to more careful monitoring of infants from pregnancies complicated by hypertension or diabetes.

In addition, two further studies are underway on the EDEN cohort: one evaluates exposures 500 nonsmoking mothers to air pollutants and must determine their impact on the growth of the fetus and the baby's health, and the other at clinical examination of three years of children, must determine whether the pre-and postnatal growth, feeding the child and hormonal factors have an impact on the bone structure of the kids