Objective: To explore the effects of total gestational weight gain( GWG)and gestational weight gain rate( GWGR) per trimester on the neonatal birth weight.
Methods: A prospective cohort study was conducted among 549 healthy pregnant women at the( 12 ± 1) th pregnant week from Chengdu City, China who delivered a singleton. Basic information about age, pre-gestational weight and so on was collected by questionnaire, while the height and weight were measured at the first time. Weight at the( 28 ± 1) th and last week before delivery was measured respectively, while the total GWG and the different trimester GWGR were calculated and assessed by Institute of Medicine( IOM) criteria( 2009). The gestational week, neonatal weight and other information were collected after delivery. Multiple non-conditional Logistic regression models were used to test the effect of the total GWG/GWGR per trimester on neonatal birth weight.
Results: The total GWG was( 16. 2 ± 4. 6) kg. The prevalence of abnormal total GWG was 59. 1%, the excessive GWG was 44. 3%. The prevalence of insufficient GWGR in the first trimester was 44. 3%. In the second, third, the second and third trimester, the prevalence of excessive GWGR were 63. 6%, 55. 7% and 65. 8%, respectively. After adjusting the age at delivery, pre-pregnancy body mass index, gestational week and other confounding factors, the result showed that compared with adequate GWG group, insufficient GWG group was increased risk of small for gestational age( SGA)( OR =2. 51, 95% CI 1. 08-5. 82), excessive total GWG group was increased risk of large for gestational age( LGA)( OR = 2. 54, 95% CI 1. 20-5. 36). Compared with adequate GWGR group in the second trimester, excessive GWGR group was decreased risk of SGA( OR = 0. 27, 95% CI 0. 13-0. 60). Compared with adequate GWGR group in the second and third trimester, excessive GWGR group was decreased risk of SGA( OR = 0. 28, 95%CI 0. 13-0. 59).
Conclusion: Abnormal total GWG among pregnant women in Chengdu City is a big problem that both excessive and insufficient GWG existed. Excessive total GWG is the independent risk factor for LGA. GWGR in the second and the second and third trimester are significantly associated with SGA.
Keywords: birth weight; gestational weight gain; large for gestational age; neonatal; small for gestational age.