[Literature library] Trimester-specific gestational weight gain rate and small for gestational age

3 min read / 07.03.2022

General Nutrition Obstetrics / Gynaecology

A Chinese study investigated the association of trimester-specific gestational weight gain (GWG) rate with small for gestational age (SGA) among underweight women^. In total, 3,839 pre-pregnancy underweight women in singleton pregnancy from the Born in Guangzhou Cohort Study (BIGCS) were included in the analysis.

Optimal GWG recommendations^{^}

Underweight (pre-pregnancy BMI < 18.5 kg/m²): 12.5—18 kg
Normal weight (pre-pregnancy BMI 18.5—24.9 kg/m²): 11.5—16 kg
Overweight (pre-pregnancy BMI 25—29.9 kg/m²): 7—11.5 kg
Obesity (pre-pregnancy BMI ≥ 30 kg/m²): 5—9 kg

Results

Overall neonatal size

SGA babies: 10.3% (397 out of 3,839)
Appropriate for gestational age (AGA) babies: 87.1% (3,342 out of 3,839)
Large for gestational age (LGA) babies: 2.6% (100 out of 3,839)

Mean GWG

Mothers with SGA babies: 13.7 kg (SD 3.7)
Mothers with AGA babies: 14.9 kg (SD 3.9)
Mothers with LGA babies: 17.3 kg (SD 5.1)

Association of GWG with the risk of SGA

Total GWG was shown to be inversely associated with SGA (adjusted OR [aOR] 0.91, 95% CI 0.89, 0.94)
Inadequate GWG was associated with higher risk of SGA^# (aOR 1.52, 95% CI 1.19, 1.93)
Excessive GWG was associated with decreased risk of SGA^# (aOR 0.54, 95% CI 0.37, 0.78)

Association of GWG rate with the risk of SGA

The GWG rate (per 0.5 kg/ week increase) during the first (aOR 0.40, 95% CI 0.30, 0.55) and second trimester (aOR 0.40, 95% CI 0.30, 0.55) were shown to be inversely associated with the risk of SGA
During the first trimester, inadequate GWG rate was not associated with SGA, while excessive GWG rate was associated with a decreased risk of SGA* (aOR 0.70, 95% CI 0.51, 0.96)
During the second trimester, inadequate GWG rate was associated with a significantly increased risk of SGA* (aOR 1.58, 95% CI 1.14, 2.20)
During the third trimester, no significant association between risk of SGA and excessive or inadequate GWG rates were observed*

^According to the Institute of Medicine (IOM) guidelines
#Compared to the group with adequate total GWG
*Compared to the group with adequate GWG rate

Link to the abstract:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8818159/pdf/12884_2022_Article_4433.pdf

Reference:

Wei X et al. Gestational weight gain rates in the first and second trimesters are associated with small for gestational age among underweight women: a prospective birth cohort study. BMC Pregnancy Childbirth. 2022;22(1):106.

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WYE-EM-019-FEB-22