ABSTRACT: Overweight and obesity during pregnancy are risk factors for a large number of perinatal complications, both for the mother and the infant. Risk stratification and early interventions are therefore highly clinically important to minimize future complications. Currently, body mass index (BMI) in early pregnancy is used for risk stratification of pregnant women, but a disadvantage of BMI is that it does not distinguish muscle from fat tissue and central from peripheral adiposity. Maternal fat distribution is suggested to be a better predictor than BMI of obesity-related adverse pregnancy outcomes, with central adiposity posing a greater risk than peripheral subcutaneous fat. With this study, we aimed to systematically review the evidence of what impact maternal central adiposity in early to mid-pregnancy or at most 365 days prior to conception has on infant anthropometry and perinatal morbidity. The databases PubMed/MEDLINE, Web of Science Core Collection, CINAHL, SCOPUS, Clinical Trials, and Open Grey were searched from inception until November 2019. Eligible studies assessed the association between maternal central adiposity, in early to mid-pregnancy or at most 365 days prior to conception, and any of the following infant outcomes: preterm delivery (< 37 weeks of gestation), birthweight, macrosomia, large for gestational age, congenital malformations, hypoglycemia, hyperbilirubinemia, care at neonatal intensive care unit, and death. Two authors independently screened titles and abstracts, read the included full-text studies, and extracted data. The Newcastle-Ottawa Quality Assessment Scale for cohort studies was used to evaluate the quality of and risk of bias in the studies. A total of 720 records were identified, 20 full-text studies assessed for eligibility, and 10 cohort studies included in the review. The results suggest that central adiposity in early to mid-pregnancy or at most 365 days prior to conception may contribute to increased birthweight and increased likelihood of delivery by cesarean section. There is also some evidence of associations between central adiposity and preterm delivery (< 37 weeks of gestation), and admission to neonatal intensive care unit. A meta-analysis was not possible to perform due to substantial heterogeneity among the included studies regarding the exposure, outcome, and statistical methods used. Hence, central adiposity in early to mid-pregnancy or at most 365 days prior to conception could be a possible risk marker in addition to BMI for risk stratification of pregnant women. However, since the topic is only scarcely researched, and the results not unanimous, more studies are needed to further clarify the associations between maternal central adiposity and adverse neonatal complications, before any altered recommendations of guidelines could be made. To enable a future meta-analysis, studies using similar methods for central adiposity assessment,and similar outcome measures, are required.
