Karolinska Institute. Sweden: Bariatric surgery has both a positive and negative
influence on the risk of complications during subsequent pregnancy and
delivery, concludes a new study from Karolinska Institutet. The results,
which are published in the
New England Journal of Medicine
, indicate that maternal health services should regard such cases as risk pregnancies.
Pregnant women with obesity run a
higher risk of developing complications during pregnancy and risks of
fetal/infant complications are also higher. There has been a sharp rise
in the number of women becoming pregnant after bariatric surgery; in
2013 almost 8,000 such operations were performed in Sweden, 80 per cent
of which were on women.
“The effects of bariatric surgery on health outcomes such as
diabetes and cardiovascular disease have been studied, but less is known
about the effects on pregnancy and perinatal outcomes,” says the
study’s lead author, Kari Johansson, PhD, from the Department of
Medicine in Solna. “Therefore we wanted to investigate if the surgery
influenced in any way the risk of gestational diabetes, preterm birth,
stillbirth, if the baby was small or large for its gestational age,
congenital malformations and neonatal death.”
Using data from nationwide Swedish health registries, the
researchers identified 596 pregnancies to women who had given birth
after bariatric surgery between 2006 and 2011. These pregnancies were
then compared with 2,356 pregnancies to women who had not been operated
upon but who had the same body mass index (BMI, weight divided by height
squared) as the first group prior to surgery.
What researchers found was that the women who had undergone
surgery were much less likely to develop gestational diabetes – 2%
compared to 7% – and give birth to large babies. Just over 22% of women
in the comparison group had babies that were large for gestational age,
and barely 9% of the operated women. On the other hand, the operated
women were twice as likely to give birth to babies who were small for
gestational age, and the pregnancies were also of shorter duration.
“Since bariatric surgery followed by pregnancy has both
positive and negative effects, these women, when expecting, should be
regarded as risk pregnancies,” says Dr Johansson. “They ought to be
given special care from the maternal health services, such as extra
ultrasound scans to monitor fetal growth, detailed dietary advice that
includes checking the intake of the necessary post-surgery supplements.”
The study was financed by the Swedish Research Council, The
Obesity Society, Karolinska Institutet and the Stockholm County Council.
Publication:
“
Outcomes of Pregnancy in Women with Prior Bariatric Surgery
”, Kari Johansson, Sven Cnattingius, Ingmar Näslund, Nathalie Roos,
Ylva Trolle-Lagerros, Fredrik Granath, Olof Stephansson, & Martin
Neovius,
New England Journal of Medicine
online 26th February 2015.