Research Article: Birthweight and pregnancy outcomes in obese class II women with low weight gain: A retrospective study

Date Published: May 20, 2019

Publisher: Public Library of Science

Author(s): Estelle Roussel, Salma Touleimat, Laurence Ollivier, Eric Verspyck, Diane Farrar.


To determine if weight gain below the institute of medicine (IOM) guidelines improves pregnancy outcomes and influences birthweight for women with class II obesity.

We retrospectively included 996 women with class II obesity with singleton gestations and delivered at term in two hospitals providing level III maternal care between January 2006 and December 2015. Women were classified into three groups: weight gain within IOM recommendations (≥5-≤9kg), low weight gain (≥0-<5kg), and weight loss (<0kg). Maternal complications and birth weight were reported in all groups. The group presenting weight gain within IOM recommendations was considered as the reference group. 424 women (42.5%) constituted the reference group and presented weight gain within IOM recommendations; whereas 370 (37.1%) presented low weight gain and 202 (20.3%) presented weight loss. The rate of birthweight above 4000 g was reduced in women with low weight gain (odds ratio (OR) = 0.62 [0.42–0.93]; p = 0.02) and in women with weight loss (OR = 0.58 [0.35–0.96]; p = 0.02). However, the rates of small for gestational age fetuses (SGA) < 10th percentile was increased in women with weight loss (OR = 1.63 [1.03–2.58]; p = 0.02). Maternal and neonatal complications were not significantly different between groups. While low weight gain in women with class II obesity may reduce macrosomia without excessive risk of SGA, it has no effect on maternal and neonatal complication rates.

Partial Text

The prevalence of maternal obesity is increasing in developed countries and estimated to be around 12% in France [1]. Maternal complications associated with obesity are increased rates of cesarean section, preeclampsia, gestational diabetes and post-partum haemorrhage (2). Neonatal complications associated with maternal obesity are mainly linked to macrosomia, which in turn increases the prevalence of shoulder dystocia, neonatal asphyxia and traumatic lesions related to delivery [2]. In addition, fetal complications i.e. prematurity, stillbirth, congenital abnormalities, and childhood and adolescent metabolic disorders are also more frequently reported in obese women [2].

This retrospective study included obese women followed up in two hospitals providing level III (Rouen University Hospital) and II (Belvedere General Hospital) maternal care belonging to the same territorial health care system and using similar protocols of care. Data were recorded retrospectively using computer-based charts for 10 years starting on the 1st of January 2006 and ending on the 31st of December 2015. Data were collected prospectively and systematically during the pregnancy follow-up by doctors or midwives. Inclusion criteria were: singleton pregnancy, term delivery (between 37 and 41 weeks of gestation), and a BMI comprised between 35 and 40 kg/m2. Women were excluded if their weight gain exceeded 9 kg, if the last weight measure was recorded more than a week preceding delivery and in cases of incomplete/missing data. The Committee for the Protection of Person Nord-Ouest I has examined this work and found it conforms to the ethical standards and to the scientific requirements applicable to biomedical research. Date of approval: 26 March 2018. Reference number: E2018-26

During the study period, 1668 pregnant women with class II obesity were followed up and 996 of them were included in the study (Fig 1). Exclusion criteria were pregnancy weight gain of more than 9kg (n = 541), preterm delivery (n = 90), multiple pregnancies (n = 7), and incomplete medical charts (n = 34). Among these 996 women, 424 (48.6%) presented a weight gain within IOM recommendations, 370 (37.1%) presented low weight gain, and 202 (20.3%) presented weight loss.

This study demonstrates that gaining less than IOM guidelines may reduce the risk of macrosomia without increasing the risk of small for gestational age in pregnant women with class II obesity. However, no beneficial effect of a low pregnancy weight gain was observed on maternal and neonatal outcomes in obese class II women at term.

In pregnant women with class II obesity, a weight gain below IOM guidelines reduced the risk of macrosomia, while it did not increase the risk of SGA. Further studies are necessary to evaluate the impact of this low weight gain on other neonatal parameters and long-term complications.




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