Weight gain between pregnancies increases risk of birth as-phyxia

The risk of asphyxia in a second child is higher if the mother has put on weight since the birth of her first child, according to a new large Swedish registry study conducted by researchers at Karolinska Institutet and published in PLOS Medicine.

The results show that a more substantial weight gain between two pregnancies, even in women of normal weight, increases risks of neonate complications.

Offspring of overweight or obese mothers run a higher risk of perinatal complications. Asphyxia in the baby at birth is one such complication.

Increased risk

While it is already known that high maternal BMI increases the risk of asphyxia-related injuries in the neonate, the present study is the first to examine if weight-gain between two pregnancies increases the risk of asphyxia in the second baby.

“We found that the weight-gain between pregnancies increased the risk of asphyxia in a woman’s second baby,” says Martina Persson, researcher and paediatrician at Karolinska Institutet’s Department of Medicine (Solna) and at Sachs’ Children and Youth Hospital. “This was particularly salient in children of mothers who were of normal weight at the time of their first pregnancy, but who had put on weight by their second.”

The researchers used data from the Swedish Medial Birth Registry on over half a million mothers who had had their first and second babies between 1992 and 2012.

Examined associations

The health of all neonates is assessed shortly after birth using the Apgar Scale. The researchers examined associations between inter-pregnancy weight-gain and asphyxia-related complications in the second baby

(as expressed as a low Apgar score five minutes after delivery, seizures or severe breathing difficulties during the neonatal period). Several obesity-related conditions, such as chronic hypertension, preeclampsia and diabetes are themselves linked to complications in neonates, but interpregnancy weight gain increased risks of asphyxia-related complications even when the researchers excluded women with these diseases.

“Weight gain between pregnancies also increases risks of other complications related to pregnancy and infant health. The take home message is that after delivery, women should be advised to return to their prepregnancy weight,” says Dr Persson.

More than one in every three women who give birth in Sweden are overweight or obese.

The study was financed by the Swedish Research Council for Health, Working Life and Welfare and by an unrestricted grant from Karolinska Institutet. Dr Persson has a clinical post-doc position financed by Stockholm County Council.

Publication

Inter-pregnancy Weight Change and Risks of Severe Birth-Asphyxia-Related Outcomes in Singleton Infants Born at Term: A Nationwide Swedish Cohort Study
Martina Persson, Stefan Johansson, Sven Cnattingius
PLOS Medicine, published online 7 June 2016