**Background:** Maternal nutrition and optimal gestational weight gain are critical determinants of pregnancy outcomes. Inadequate dietary intake and insufficient weight gain increase the risk of low birth weight (LBW), while excessive weight gain raises risks of preeclampsia, macrosomia, and gestational diabetes. In Ghana, the national LBW prevalence is 14.2%, with higher rates in Northern Ghana (up to 26%). Limited data exist on dietary habits and their relationship with birth weight specifically in the Tamale Metropolis.
**Methods:** This health-facility-based analytical cross-sectional study was conducted from March to May 2020 in the Tamale Metropolis, Northern Ghana. A total of 316 postnatal mothers were recruited using multistage sampling (random selection of health facilities, then consecutive sampling of eligible women). Inclusion criteria were permanent residence in the metropolis, willingness to participate, and sound mental health. Exclusion criteria included chronic conditions such as cancer and diabetes. Data were collected using a semi-structured questionnaire covering socio-demographics, household assets, a food frequency questionnaire adapted from the Ghana Demographic and Health Survey, and obstetric history including weight measurements from first ANC visit to delivery and birth weight. Dietary diversity was assessed using the Minimum Dietary Diversity for Women (MDD-W) tool, classifying 10 food groups. Gestational weight gain was categorized per IOM 2009 guidelines based on pre-pregnancy BMI (using first-trimester weight as proxy). Birth weight was categorized as LBW (<2.5 kg), normal (≥2.5 to <4.0 kg), or macrosomia (≥4.0 kg). Data were analyzed using STATA 12.1. Descriptive statistics, independent t-tests, one-way ANOVA, chi-square tests, and multiple logistic regression were performed. Statistical significance was set at p<0.05.
**Key Results:** The mean age of respondents was 29.0 ± 5.3 years; 93.7% resided in urban areas, 90.5% were married, and 75.3% were Muslim. Regarding pre-pregnancy BMI, 11.4% were underweight, 52.5% normal, 28.8% overweight, and 7.3% obese. Almost all respondents consumed breakfast (97.5%) and lunch (98.7%) daily, and all (100%) consumed supper daily, but only 40.0% consumed snacks daily. Meal frequency increased across trimesters: in the third trimester, 65.0% ate more than three times daily. Dietary diversity was acceptable (≥5 food groups) in 92.4% of respondents. Daily consumption was high for dark green leafy vegetables (97.5%), meat/meat products (81.6%), legumes/pulses (85.8%), eggs (88.0%), and grains (87.0%), but low for milk/milk products (34.5% daily) and vitamin A-rich fruits/vegetables (31.3% daily). Gestational weight gain was adequate in 55.9%, excessive in 26.4%, and inadequate in 17.8%. Birth outcomes showed 85.0% normal birth weight, 11.0% LBW, and 4.0% macrosomia. Mean birth weight was 3.1 ± 0.1 kg. In bivariate analysis, factors significantly associated with birth weight included residence, maternal age, marital status, education, occupation, parity, ethnicity, religion, husband's education and occupation, weight gain, and pre-pregnancy BMI. After multiple logistic regression, only two factors remained significant predictors of LBW: pre-pregnancy underweight (BMI <18 kg/m²) (AOR=8.3, 95% CI: 6.7-15.0, p=0.001) and inadequate gestational weight gain (AOR=4.5, 95% CI: 3.9-6.5, p<0.001). Dietary diversity was not a significant predictor in the adjusted model (AOR=8.8, 95% CI: 0.6-130, p=0.11).
**Clinical Implications:** This study demonstrates that maternal pre-pregnancy BMI and gestational weight gain are strong, independent predictors of low birth weight in the Tamale Metropolis. The 11.0% LBW prevalence, while lower than the national average (14.2%) and the WHO target of <10%, indicates that LBW remains a significant public health concern. The coexistence of LBW (11.0%) and macrosomia (4.0%) reflects a double burden of malnutrition. The finding that underweight women (BMI <18 kg/m²) had 8.3 times higher odds of delivering an LBW infant underscores the need for targeted nutritional interventions before conception. Similarly, inadequate gestational weight gain increased LBW risk 4.5-fold, highlighting the importance of monitoring and supporting appropriate weight gain during antenatal care. The high proportion of women with acceptable dietary diversity (92.4%) suggests that food availability may not be the primary issue; rather, the quality and specific nutrient intake (e.g., vitamin A-rich foods, milk products) may require attention. The authors recommend holistic, multi-sectoral approaches including behavior change communication and comprehensive preconception care to address LBW. Limitations include the cross-sectional design (which cannot establish causality), potential recall bias, and restriction to facility-delivered births, which may limit generalizability to home births common in Northern Ghana.